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The surface integrity of turned and ground hardened bearing steel
Abstract
The surface integrity of the machined component has received greater attention over the last 20 years, especially in relation to high performance materials. Due to the inherent differences between abrasive machining and single point cutting, distinct surface texture patterns will be produced, which together with the associated metallurgical alterations can lead to substantial variations in component service performance. The paper compares several aspects of finish turning against grinding of hardened bearing steel, more specifically surface texture, microstructural alterations, changes in microhardness, residual stresses distribution and fatigue life. The findings suggest that for the operating parameters tested the microstructural alterations observed were confined to an untempered martensitic layer often followed by an overtempered martensitic layer. Compressive residual stresses were induced when turning and grinding and the best fatigue resistance was obtained when turning using PCBN cutting tools followed by turning using mixed alumina tools and finally by grinding.
... Chinese Journal of Mechanical Engineering 34:118 has been compared to assist in the selection of processing technology (Table 1) [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In addition, the effects of machining parameters of certain machining technology, such as cutting speed [3,[21][22][23][24], feed rate [4,22,[25][26][27], tool rake angle [28], and tool wear [29], were investigated. ...
... In most studies about the fatigue performance of machined components, the machined surface integrity, including the surface topography (e.g., surface roughness, local defects and inclusions) [30][31][32][33], residual stress [28,34,35], work hardening [36][37][38][39], and metallurgical structure changing [40][41][42], was considered as the bridge to reveal the internal mechanism of changed fatigue performance of a workpiece. However, disagreements are still observed in these studies because the tested workpiece materials, which covered steel [6][7][8][9][10], stainless steel [18], titanium alloy [15,17,20], Ni-base superalloy [13], and aluminum alloy [19], fatigue performance testing methods, and loading magnitudes vary (Table 1). ...
... With the deep research in machined surface fatigue performance, many researchers suggested that the residual stress was also an important factor that affected the workpiece fatigue property aside from surface topography [10,20,28,34]. For the effects of residual stress on fatigue performance, the researchers had reached an agreement that the compressive residual stress can improve fatigue limit and the tensile residual stress can reduce fatigue resistance [15,16,30,35,[77][78][79]. In the literature, tensile residual stress was identified as a significant factor that resulted in the poor fatigue performance of electro-discharged and laser-beam machined surfaces [17,30,80]. ...
Fatigue performance is a serious concern for mechanical components subject to cyclical stresses, particularly where safety is paramount. The fatigue performance of components relies closely on their surface integrity because the fatigue cracks generally initiate from free surfaces. This paper reviewed the published data, which addressed the effects of machined surface integrity on the fatigue performance of metal workpieces. Limitations in existing studies and the future directions in anti-fatigue manufacturing field were proposed. The remarkable surface topography (e.g., low roughness and few local defects and inclusions) and large compressive residual stress are beneficial to fatigue performance. However, the indicators that describe the effects of surface topography and residual stress accurately need further study and exploration. The effect of residual stress relaxation under cycle loadings needs to be precisely modeled precisely. The effect of work hardening on fatigue performance had two aspects. Work hardening could increase the material yield strength, thereby delaying crack nucleation. However, increased brittleness could accelerate crack propagation. Thus, finding the effective control mechanism and method of work hardening is urgently needed to enhance the fatigue performance of machined components. The machining-induced metallurgical structure changes, such as white layer, grain refinement, dislocation, and martensitic transformation affect the fatigue performance of a workpiece significantly. However, the unified and exact conclusion needs to be investigated deeply. Finally, different surface integrity factors had complicated reciprocal effects on fatigue performance. As such, studying the comprehensive influence of surface integrity further and establishing the reliable prediction model of workpiece fatigue performance are meaningful for improving reliability of components and reducing test cost.
... Estudio mediante difracción de Rayos-X de las tensiones residuales generadas por diferentes tipos de mecanizado V. GARCÍA 1 , N. ORDÁS 1 El propósito de este trabajo es la medición de tensiones residuales mediante difracción de rayos-X en materiales sometidos a diferentes tipos de mecanizado, con el fin de mostrar la importancia que tiene una correcta elección del tipo y parámetros del mecanizado en la calidad de la superficie creada, especialmente en el estado final de tensiones residuales. Se han realizado mediciones sobre distintos materiales (acero inoxidable 17/7 PH, Ti-6Al-4V y acero de herramienta F-521), mecanizados mediante torneado duro o rectificado. ...
... Los principales problemas asociados con el mecanizado de aceros de herramienta están relacionados con la integridad de la superficie (1)(2)(3)(4): tensiones residuales, martensita sin revenir (capa blanca, fase dura pero frágil), martensita sobrerevenida (fase blanda) y aparición de grietas. Durante los procesos de mecanizado la superficie de la pieza se ve afectada plástica, térmica y químicamente. ...
... La fuerza normal aplicada por la herramienta sobre la superficie de la pieza genera deformación plástica, dando lugar a tensiones residuales compresivas en la capa más superficial. La fricción entre la pieza y la herramienta es tal que genera temperaturas muy elevadas capaces de producir transformaciones de fase en las capas más superficiales del material y tensiones residuales tractivas (1,5). Estas tensiones tractivas son perjudiciales para la vida del material durante su uso, puesto que favorecen la formación y propagación de grietas. ...
The aim of the present work is the measurement of residual stresses using X-ray diffraction in materials subjected to different kinds of machining, to show the relevance of an adequate choice of machining type and parameters on the quality of the generated surface, especially in the residual stress final state. Different materials (stainless steel 17/7 PH, Ti-6Al-4V and F-521 tool steel) subjected to hard-turning and grinding have been investigated. In each case the evolution of the residual stress with distance to surface has been obtained. An integral method has been applied to determine the residual stress state by measuring the changes in the diffraction angle position. This method provides the full stress tensor and the stress gradient tensor in the longitudinal and transversal directions and in depth. X-ray diffraction measurements have allowed the evaluation of both macroscopic and microscopic residual stresses (the latter only qualitatively).
... After turning hardened AISI 52100 bearing steel (62 HRC), Abrão and Aspinwall [28] found a white untempered martensite layer 2 µm deep, followed by an overtempered martensite layer, however, cracks, tears, laps and recast layer were not evident. Matsumoto et al. [29] did not observed any significant structural changes on the cross sections of AISI 4340 steel (54 HRC) samples subjected to milling, with plastic deformation taking place very near the surface. ...
... The influence of the operation and tooling on microhardness variation of AISI 52100 bearing steel (62 HRC) after dry turning with polycrystalline cubic boron nitride (PcBN) and mixed alumina (Al 2 O 3 +TiC) inserts was studied by [28]. The results indicated that after turning, a maximum hardness value of approximately 900 HV 0,025 was obtained near the surface, decreasing to a minimum 4 µm below, followed by an increase to the bulk hardness (750 HV 0,025 ) at approximately 10 µm beneath the surface. ...
... Compressive residual stresses were induced after turning AISI 52100 bearing steel [28] with fresh and worn PCBN and mixed alumina inserts. The difference between the tools grades was not significant, nevertheless, the intensity and depth of the stresses was higher when worn inserts (average flank wear VB B =0,27 mm) were tested (maximum residual stress of approximately -600 MPa at a depth of 20 µm below the surface). ...
Surface integrity comprises the study of the alterations induced during the manufacture of a component that might affect its properties and service performance. Therefore, additionally to geometric irregularities (surface texture and both dimensional and geometric deviations), the study on surface alterations (such as metallurgical alterations, cracks and residual stresses) induced by hard-part machining is of utmost importance, especially in the case of components subjected to dynamic loading. Consequently, this chapter is focused on the investigation of the influence of tool material and geometry and cutting parameters on the surface integrity of components subjected to hard-part machining and, when applicable, comparisons are drawn with grinding and non-conventional processes, especially electrical discharge machining (EDM).
... µm. Abrao and Aspinwall [1996] were able to produce a surface finish with roughness value of 0.14 µm. ...
... The results also indicated that hard turned surfaces always exhibited comparable fatigue strength to ground surfaces. Abrao and Aspinwall [1996] performed axial fatigue tests on hard turned bars, and found that bars turned with PCBN tools performed better than bars machined with alumina tools and also better than ground surfaces. Matsumoto et al. [1999] showed similar results, indicating that hard turned and super-finished components had comparable or improved fatigue life. ...
The generation of huge amount of heat in high production machining at high cutting velocity and feed rate shortens the tool life and deteriorates the job quality. The conventional cutting fluids are not that effective in such high production machining particularly in continuous cutting of materials like steels. Because of these some alternatives has been sought to minimize or even avoid the use of cutting fluid in machining operations. One of these alternatives is machining with minimum quantity lubricant (MQL). It is a mixture of impinging of least amount of cutting fluid along with highly compressed air through a small nozzle results in reducing the heat produced during metal cutting. The main objective of the present work is to make an experimental investigation on the role of MQL in turning hardened steel by uncoated carbide insert (SNMG 120408) in respects of chip formation, chip-tool interface temperature, tool wear and surface roughness. The result indicated that the machining with MQL performed much better than dry machining mainly due to reduction in cutting zone temperature enabling favorable chip-tool interaction. This also facilitated the reduction in tool wear in leading to enhance tool life and surface finish.
... Since the commercial coming of ceramic and cubic boron nitride (CBN) tools in mid-1980s [3], it has been proved by several works that grinding may be satisfactorily replaced by hard machining when considering surface integrity of the part [1,[4][5][6][7]. ...
... Therefore, due to the atomic level action, the crater wear has a smooth aspect. Crater wear is also stimulated by the presence of a chamfer in the tool edge and tends to be located at this site [6,25]. ...
Hard turning is becoming an usual way to replace grinding operations and is performed with ceramics and cubic boron nitride tools. However, tool inserts are brittle and may be subjected to wear and damage mechanisms like chipping and breakage. The damages are intensified in internal turning operations, where the tool holder presents lower rigidity than in external turning, making it subjected to higher vibrations. Most works analyze chatter (unstable cut) conditions, and a gap remains over the effects of stable cut vibrations. Therefore, this work conducted internal turning tests of hardened AISI 4340 steel in a 24 full factor design (tool holder material, overhang, cutting speed and feed) in order to verify the effects of these factors on tool vibration, tool life and wear mechanisms. Under stable cut, tool accelerations were 2 times higher for steel bars, when compared to carbide bar. Tool life (in terms of volume of material removed) was not affected by tool vibration and remained around 120,000 mm3 of material removed. The main conclusion of this work was that tool vibration, in the levels obtained in this work, did not influence tool life, but its growth made tool wear mechanism to change from diffusion to abrasion.
... In many applications, hardened steel turning has replaced grinding, offering significant cost reduction, and increase in productivity. Abrão and Aspinwall [6] noted that PCBN and ceramics were introduced in hardened material machining owing to their high hot hardness and relatively low solubility in iron. ...
... Abrão and Aspinwall [6] realized that turning is more susceptible to variations in machining parameters than the grinding process since during testing, it was possible to observe both tensile and compressive residual stress distributions. This susceptibility was also observed by Navas et al. [33] who pointed out that the distribution of residual stress on the surface of a turned part is dependent on the type of material to be machined, type of cutting tool (geometry and coating), machining parameters (cutting speed, feed rate, and cut depth), and cooling system. ...
The development of new cutting tool materials favors the hardened steel turning process, which has in some cases replaced the grinding process. Thus, this study evaluates the machined surface of hardened AISI 4340 steel via turning and grinding operations. The turning process evaluated the effects of the cutting tools (material, grade, and coating) and the process parameters (cutting speed and cooling condition). In the grinding process, the effects of the plunge rates and volumes of removed material Zw were evaluated. The machined surface was evaluated by amplitude roughness (Ra, Rt, Rp, and Rz), functional (Kp, Rk, Rpk, and Rvk), and statistical parameters (Rsk and Rku) and by the type and magnitude of induced residual stress (compression and tensile). In general, the turning process displayed the best results in the roughness parameters by promoting a better surface finish, mainly when the parts were machined at a cutting speed of 300 m/min. The increased cutting speed provided better surface integrity. The ceramic tool CC6050 presented the best performance, followed by the polycrystalline boron nitride (PCBN) and ceramic CC650 tools under cooling and dry cutting conditions. With respect to the residual stress, the grinding process induced compressive residual stresses in all tested conditions. On the other hand, turning-induced tensile stresses when using ceramic cutting tools (class CC650 and CC6050) and compressive stresses when using a PCBN cutting tool (class CB7115) were examined. In general, the use of cutting fluid in turning process did not provide a better performance in relation to the dry cutting condition. Based on the obtained results, the turning of hardened materials is a viable alternative to the grinding process.
... However, microstructure is not the single factor that determines the surface integrity. Surface integrity, which influences the fatigue crack initiation and propagation, includes microstructure, residual stress, micro-hardness, etc [18,19]. To obtain the designed shape and surface finish, components always need to be machined after heat treatment. ...
... Similar results were also indicated by Refs. [19,21]. Although a few researchers had made significant contributions to the academic field of small fatigue crack behavior of GH4169 and IN718, relatively few researches considered the effect of residual stress in machined surface. ...
We investigated the small fatigue crack behavior of alloy GH4169 by using single-edge-notch tension specimens. Residual stress introduced by machining process was taken into consideration, and two stress levels were selected. A comparison was made between the experimental results of specimens with and without machining-induced residual stress. The results indicated that fatigue cracks of the two types of specimens initiated from surface inclusions or grain boundaries. For both types of specimens, small cracks grew very slowly when the crack lengths were less than 500 μm. The small crack growth might decelerate and retard temporarily for the existence of grain boundaries. The residual stress effect on crack growth can be identified at σmax = 380 MPa, i.e., compressive residual stress might impede the crack growth. However, this phenomenon was indistinguishable at σmax = 410 MPa.
... Shot peening technology can improve surface integrity of metal materials (surface roughness, residual stress, hardness, microstructure, etc.). The increase of surface roughness or even surface cracking caused by shot peening will seriously reduce the fatigue strength and life of materials [3,4]. However, surface residual compressive stress and surface hardening can suppress the initiation and extension of fatigue cracks, and these effects are very useful to prevent or delay component failure [5][6][7]. ...
... Figure 14 shows the stress distribution at the root of notched specimens before shot peening. The relative stress gradient under external load (σ tf ) can be obtained by Equation (3). The σ max is 1085 MPa and the value of RSG is 0.36. ...
Fatigue life prediction for the notched components is an essential step within the design process of machines. Fatigue strength and life prediction of 40Cr notched steel before and after shot peening were studied. Fatigue fracture of specimens treated by three shot peening intensity parameters was discussed. The life prediction considering residual stress, work hardening and surface roughness caused by shot peening was analyzed. The results indicated that fatigue strength was obviously improved after shot peening and the improvement effect was gradually enhanced with the increase of shot peening intensity. The predicted values based on Rz coefficient showed a good correspondence with the experimental data.
... The turning operation of hardened materials, also called hard turning, is characterized by having high flexibility and the ability to produce complex geometry parts, in low number of steps and reduced machine preparation time, and can be performed without the use of fluid, reducing costs and consequent environmental impact 2 . Due to these qualities, combined with work quality generated parts resulting from ISO IT6 and surface roughness of 0.2 to 0.3 µm the process of turning hardened materials has been replacing grinding in finishing operations 15 . ...
... The well-known theoretical expression (1) for roughness evaluation takes into account only the combination of the tool tip feed and radius 15 ...
This work was based on the surface integrity analysis of hardened steel, AISI 4317 case carburized, quenched and tempered with 58 HRC, obtained by a turning operation executed with CBN (cubic boron nitride) tool, varying three basic cutting parameters (cutting speed, feed rate and cutting depth). The surface integrity characterization was conducted analyzing the behavior of the surface roughness Ra, residual stresses and with layer presence after turning. Also, the cutting forces were measured. The experimental planning used was a central composite design. The results and data were statistically treated by the Statistica software, enabling the generation of a mathematical model, relating the dependent variables with the independent variables. The roughness values Ra obtained after the experiments ranged from 0.31 to 2.8 µm, providing an indication that is possible to replace grinding process by hard turning using CBN tools that could reduce machining time and costs. The hard turning process generated compressive residual stresses profiles and white layer formation, from 1.1 to 5.1 µm, on the surface of the samples. The penetration force showed the highest values for the turning forces measurements. The lowest values for the cutting parameters represented the optimized surface integrity of the AISI 4317 steel.
... Surface residual stresses in the axial and hoop directions are associated with individual microstructural patterns. Specifically, compressive residual stresses in the hoop and axial directions are evident when the workpiece's surfaces contain continuous white layers [39]. The main cause of compressive residual stress formation in samples exhibiting continuous white layers to contribute volume expansion is phase transformation. ...
... The cracks with depth of up to 5 lm in the surfaces produced by turning can be compensated for by compressive residual stresses, which further decreases the applied tensile stress. In a similar manner, turning becomes more favourable than grinding with respect to the fatigue behaviour of hardened bearing steel [39]. HSM with the proper machining conditions might increase fatigue strength [1]. ...
A correlation between machining process and fatigue strength of machined components clearly exists. However, a complete picture of the knowledge on this is not readily available for practical applications. This study addresses this issue by investigating the effects of machining methods on fatigue life of commonly used materials, such as titanium alloys, steel, aluminium alloys and nickel alloys from previous literature. Effects of turning, milling, grinding and different non-conventional machining processes on fatigue strength of above-mentioned materials have been investigated in detail with correlated information. It is found that the effect of materials is not significant except steel in which phase change causes volume expansion, resulting in compressive/tensile residual stresses based on the amounts of white layers. It is very complex to identify the influence of surface roughness on the fatigue strength of machined components in the presence of residual stresses. The polishing process improves the surface roughness, but removes the surface layers that contain compressive residual stresses to decrease the fatigue strength of polished specimens. The compressive and tensile residual stresses improve and reduce fatigue strength, respectively. Grinding process induces tensile residual stresses on the machined surfaces due to high temperature generation. On the other hand, milling and turning processes induce compressive residual stresses. High temperature non-conventional machining generates a network of micro-cracks on the surfaces in addition to tensile residual stresses to subsequently reduce fatigue strength of machined components. Embedded grits of abrasive water jet machining degrade the fatigue performance of components machined by this method.
... The first aspect is geometric irregularities on the surface, and second the metallurgical alterations of the surface and the surface layer. This second aspect has been termed surface integrity which was traditionally quantified solely in terms of observed surface cracking, but recent studies have attempted to broaden the concept by an examination of all the effects induced by a machining process [8]. Surface integrity is described as the relationship between surface geometric values and the physical properties such as residual stress, roughness, hardness, and microstructure of the surface layers. ...
... Surface residual stresses in the axial and hoop directions correlate with each microstructural pattern. Specifically, compressive residual stresses in the axial and hoop directions are noted when there are continuous white layers on the surface of the workpiece [8]. The primary reason for compressive residual stress formation in samples exhibiting continuous white layers is volume expansion accompanying phase transformation. ...
... Los principales problemas asociados con el mecanizado de aceros de herramienta están relacionados con la integridad de la superficie [1][2][3][4][5][6] : tensiones residuales, martensita sin revenir (capa blanca, fase dura pero frágil), martensita sobrerevenida (fase blanda) y aparición de grietas. Durante el mecanizado se inducen tensiones residuales en la superficie e inmediatamente bajo ésta, que pueden afectar a la vida en servicio de la pieza. ...
... Por el contrario, en el caso de torneado con ranura, se observa (Figura 6 (b)) una capa superficial de menos de 5 µm de espesor, de estructura muy diferente al resto del material. Ésta parece ser la denominada "capa blanca" [1,4,5] . El espesor de esta capa coincide con el espesor en el que se tiene un estado fuertemente tractivo de tensiones, y como se mencionará a continuación, en esta capa blanca se observa también un incremento notable de dureza y de fracción de austenita retenida. ...
Machining operations induce plastic deformation and heat generation in the near surface area of the machined part, giving rise to residual stresses. Depending on their magnitude and sign, these stresses can be detrimental or beneficial to the service life of the part. The final stress state depends on the machining process applied, as well as on the machining parameters. Therefore, the establishment of adequate machining guidelines requires the measurement of the residual stresses generated both at the surface and inside the material. In this work, the residual stresses generated in F-522 steel by two hard turning (conventional and laser assisted) and two grinding (production and finishing) processes were measured by X-ray diffraction. Additionally, depth profiles of the volume fraction of retained austenite, microstructure and nanohardness were obtained in order to correlate those results with the residual stress state obtained for each machining process. It has been observed that turning generates tensile stresses in the surface while grinding causes compressive stresses. Below the surface grinding generates weak tensile or nearly null stresses whereas turning generates strong compressive stresses. These results show that the optimum machining process (disregarding economical considerations) implies the combination of turning plus elimination of a small thickness by final grinding.
... In contrast, the introduction of grinding does not result in a significant increase in peak-to-valley roughness due to the fine abrasive grains on the grinding wheel. Additionally, the peak-to-peak spacing in grinding is much smaller than in fine turning [23]. As the fine grinding allowance increases, Rp and Rv initially decrease and then increase. ...
The final processing techniques for ultra-high strength steel typically involve turning and grinding. The selection of processing parameters is crucial in determining the surface integrity and fatigue behavior of the resulting parts. This study investigates the surface integrity of 45CrNiMoVA steel, including surface roughness, residual stress, and microhardness, as well as its low cycle torsional fatigue behavior, such as fatigue life and fatigue fracture morphology. The effects of different turning and grinding allowance conditions on surface integrity parameters and fatigue behavior are examined. In addition, this text analyzes the differences between the surfaces produced by turning and grinding. It examines the microscopic factors that affect surface quality and fatigue life by considering crystallographic characteristic parameters. The results show that the specimens that subjected to fine turning exhibit poor surface morphology, high compressive residual stress, high microhardness, and the longest fatigue life. Among the various grinding allowance distributions, RFGF1 is considered relatively optimal. It consists of a rough grinding allowance of 0.45 mm and a fine grinding allowance of 0.15 mm, with the use of cutting fluid.
... This means that wiper inserts are capable of maintaining equivalent surface quality at a feed rate that is double that of conventional inserts, an outcome unattainable by the latter under similar conditions [23,30,31]. In other words, under certain machining parameters, wiper inserts can achieve a surface quality comparable to that of grinding operations [32][33][34]. When a wiper insert coated with carbide is used in cutting stainless steel, it reduces the peak-to-valley surface roughness and enhances the material removal rate (MRR) [35]. ...
Despite the prevalent application of 18% Ni maraging steel in critical sectors such as aerospace and automotive due to its unique characteristics, including high ductility, yield strength, and hardenability, its machining presents enormous challenges, categorizing it as a difficult-to-machine material. The cutting tool's geometry is crucial in machining, significantly affecting chip formation, cutting forces, power consumption, and obtainable surface quality. In particular, wiper insert technology, characterized by its multi-radius design, offers an increased contact area compared to conventional inserts, potentially enhancing the quality of the machined surface. This study explores the effectiveness of wiper inserts in the face-milling of maraging steel 350, conducting a comparative analysis across three distinct machining setups. These setups vary by alternating the number of wiper and conventional inserts within the same cutter, thereby examining the influence of insert configuration on machining outcomes. The research employs a reliable and well-established statistical approach to evaluate how different variables, such as cutting speed and feed rate, affect surface quality, power consumption, and material removal rate (MRR). It also sheds light on the material removal mechanisms facilitated by each type of insert. The findings reveal that incorporating a higher number of wiper inserts significantly enhances the surface finish but concurrently increases power consumption. Thus, the study successfully identifies an optimal set of process parameters that attain a balance between achieving superior surface quality and maintaining energy efficiency in the machining of maraging steel 350. This balance is crucial for optimizing manufacturing processes while adhering to the stringent quality and sustainability standards required in aerospace and automotive manufacturing.
... Grinding is one of the most critical manufacturing processes in machining bearing rings. In most cases, bearing rings with lower surface roughness have higher chemical stability and hence longer service lives and better bearing performance [1,2]. However, the shape accuracy and sharpness of the grinding wheel will gradually decrease as the grinding wheel grinds the bearing rings continuously. ...
To improve the surface quality of GCr15 bearing ring grinding and to address the problem of difficult selection of dressing parameters in the grinding wheel dressing process, a study was conducted on the optimal selection of parameters when dressing white alumina (WA) grinding wheel with ultrasonic-assisted diamond roller using response surface methodology (RSM) and genetic algorithm (GA). Firstly, we analyzed the action characteristics of the dressing parameters during ultrasonic-assisted roller dressing (UARD). Secondly, the Box–Behnken method was utilized to design the UARD experiments for the WA wheel. On the basis of experimental data, a prediction model for the surface roughness (Ra) of bearing ring grinding was developed. The influence law of dressing parameters (dressing speed ratio qd, crossfeed velocity vfd, dressing depth ad, ultrasonic amplitude AL) and their interactions on Ra was qualitatively analyzed using RSM. Moreover, it was found that the dressing speed ratio (qd) and the ultrasonic amplitude (AL) were the main influencing factors on Ra. According to the optimization model of dressing parameters established by the improved genetic algorithm (IGA), we have obtained the optimal combination of dressing parameters: qd = 0.4718, vfd = 50.001 mm/min, ad = 42 μm, and AL=1.29 μm. A surface roughness of Ra = 0.4175 m was attained by grinding GCr15 bearing ring with WA wheel dressed with the optimal dressing parameters. Its surface quality was significantly enhanced, and its surface roughness was reduced by 9.77~52.68% when compared to prior optimization. Finally, the results of the validation experiments show a certain level of accuracy and reliability in both the surface roughness prediction model and the dressing parameter optimization model. The study results show that the dressing parameter optimization method can effectively improve the grinding quality of bearing rings and is of value for engineering applications.
... The top layer is the white layer with a thickness of fewer than 20 μm, whose main components are austenite, martensite mixed with α phase and γ phase, and other carbides [50,51]. Alexandre et al. [52] used polycrystalline cubic boron nitride tools and ceramic tools to cut hardened bearing steel AISIE 52,100 and considered that the micro-structure of the workpiece top surface and subsurface consisted of a white untempered layer and a black over-tempered layer. Hosseini et al. [53] analyzed the effect of cutting speed and tool wear on the micro-structure of white and dark layers in hard turning of high carbon chromium steel GCr15. ...
The surface integrity of bearing steel materials largely determines the life of mechanical parts like bearings and gears. Optimizing the process parameters or applying surface modification technology can improve the surface integrity of materials. In this paper, the definitions and characteristics of the evaluation parameters of surface integrity and their influences on mechanical part performance were reviewed. The influences of machining processes (forging, cold rolling, heat treatment, turning, grinding, and super-finishing) for bearing steel materials on parameters related to surface integrity including metal streamline distribution, surface roughness, surface waviness, surface defects, micro-structure, residual stress, and micro-hardness were summarized. Several typical surface modification technologies applied to bearing steel materials were summarized, including surface coating technology, chemical heat treatment technology, ion implantation technology, reinforced grinding technology, shot peening technology, and composite modification technology. Finally, two new surface modification technologies which can be applied to bearing steel materials in the future were introduced (ultrasonic surface rolling process and laser shock peening). It can provide certain research directions and theoretical references for improving the surface integrity of bearing steel material in this paper.
... 2 On the other hand, bearings are generally regarded as components which have a high surfaceintegrity and hence the fatigue problems are usually attributed to defects within the material itself. 3,4 A lot of efforts have been input by scientific and engineering communities to understand the material fatigue properties and to improve the damage tolerance of the material. 5,6 Rotatory bending fatigue (RBF), and rolling contact fatigue (RCF) are two representative fatigue modes in bearings. ...
A new double vacuum melting route (conventional second refining + vacuum arc refining (CSR + VAR)) with 33% lower production cost than the traditional VIM + VAR route has been tried. Compared with the CSR route, the CSR+VAR route reduces the average inclusion size from 27.1 ± 12.3 um to 13.7 ± 2.4 um, and the CSR + VAR steel processes a 13.1% higher RBF fatigue strength and a 3-times longer RCF L10 life. The crescent-shaped GBF zone, normally found in high-strength steels’ very high cycle fatigue regimes beyond 10^7 cycles but normally under a much lower stress amplitude, appears around inner inclusions on the CSR + VAR steel RBF fracture surfaces in high cycle fatigue regimes beyond 3 × 10^5 cycles. The development of GBF zones is estimated to account for 79%-90% of the RBF fatigue life. The average crack propagation rate (da/dN) for GBF zones varies from 1.3 × 10^-12 m/cycle to 24 × 10^-12 m/cycle and increases with the stress amplitude.
... Bearing steel is commonly used in the manufacture of mechanical bearings in various fields such as automotive engines, gas turbines, and aerospace vehicles [1][2][3]. With the development and requirement of high-speed railway and aerospace technologies, the ambient temperature of the bearings became higher. ...
The effects of traditional heat treatment (quenching and then tempering) and deep cryogenic treatment on the microstructure and mechanical properties of a low-carbon high-alloy martensitic bearing steel were studied by Rockwell hardness test, X-ray diffractometry, scanning electron microscopy and transmission electron microscopy. The results show that the deep cryogenic treatment promotes the transformation of the retained austenite to martensite during cooling, which leads to the hardness of the sample after deep cryogenic treatment higher than that at the quenched state. Also, the carbon content in the martensite matrix after different treatments was calculated and the results indicated that deep cryogenic treatment can promote the segregation of carbon atoms in martensite to dislocations. The segregated carbon atoms act as and grow into nuclei for the formation of fine carbide particles during subsequent tempering. And this resulted in the fact that the hardness of the tempered experimental steel after deep cryogenic treatment is higher than that without deep cryogenic treatment.
... requirements [16]. Thus, the roughness constraint can be formulated as: ...
In order to improve the grinding efficiency of bearing raceways, a multi-objective optimization method that considers the surface integrity constraints of the bearing raceway is proposed. Appropriate design points are selected through an orthogonal test, and a response surface model of the grinding parameters along with the response output is established on the basis of the test results. Explicit expressions for the grinding force and roughness are formulated, and the constraints necessary to meet the quality requirements are obtained. The genetic algorithm NSGA-II is applied to the multi-objective optimization of grinding time and material removal rate, and the Pareto set is solved. The results of the study show that using optimized grinding parameters can reduce the grinding time and material removal rate, and can also help broaden the available knowledge base on high-speed and high-efficiency grinding technology.
... Similar results were found by Jochmann and Wirtz [1999], who produced consistent peak-to-valley finishes below 1.0 µm, roundness below 0.2 µm, and cylindricity below 1.0 µm. Abrao and Aspinwall [1996]were able to produce a surface finish with roughness value R a as low as 0.14 µm. ...
Modern manufacturing industries are seeking different alternatives to attain the need of higher machining speeds, lower wastage and a better product quality as well as reducing the cost of the manufacturing process.An approach to this problem is considering high speed machining but high speed machining at high speeds and feeds generates large heat and high cutting temperature, which shortens the tool life and deteriorates the job quality. To reduce this high temperature machining of hardened medium carbon steelneeds large quantities of cutting fluid to be applied which not only incur expenses but also can cause grave environmental and health hazards. Dry machining might be an alternative in this context and is totally free from the problems associated with cutting fluid but is difficult to implement on the existing shop floor as it needs ultra-hard cutting tools and extremely rigid machine tools. The manufacturing industries hence are looking to mitigate these problems by experimental investigations and by adoption of advanced techniques such as cryogenic cooling, high-pressure coolant, and minimum quantity lubricant (MQL) application. Among these, Minimal Quantity Lubrication machining is found to be quite effective in improving tool life and surface finish.
In this research work surface milling of AISI 4140 steel (40 HRC)was investigated with pulsed jet Minimum Quantity Lubricant (MQL) applicator using straight oil as the cutting fluid. The investigation was carried upon comparing the performance of MQL applicator on the basis of tool wear, cutting force, and surface finish. The effects of different cutting parameters were compared at different combinations of feed, depth of cut and cutting conditions. A pulsed jet MQL applicator was designed and developed with the help of full factorial analysis (Design of Experiment) and it was ensured that the cutting fluid can be applied in different timed pulses and quantities at critical zones during surface milling.An investigative comparison with dry milling under same conditions has been done to evaluate the relative performance of hard milling with MQL applicator. It was observed that the MQL applicator system for surface milling on hardened steel can bring forth better performance when compared to dry milling.
... Surface topography and surface roughness are the key geometric characteristics of the surface state of materials that have a great influence on service performances such as fatigue [17,18]. Surface roughness is a physical quantity that characterizes the degree of plastic deformation of the entire surface of the material and directly reflects the laser-induced stress effect on the surface of the material. ...
High-energy short-pulse lasers can induce significant shock waves, and they have been increasingly used in the field of material processing. The authors summarize the effects of pulsed laser-generated stresses on the surface topography of materials, introducing their related applications, and they highlight several unpredicted surface structures of different scales that were formed by laser shocks and reported in recent years. Laser-induced shock waves can lead to severe plastic deformation of material surfaces. The effects that the initial surface state of the material to be processed, the absorption layer, and the shape of the laser spot have on the plastic deformation of the surface are summarized in this paper. The reasons why lasers cause the formation of different sizes of pits on the surface of materials and the shape characteristics of the pits are both described in detail. Additionally, a series of special structures of smaller sizes reported in recent years, such as surface relief and craters, are introduced. This paper has important reference value and guiding significance for researchers to further explore the mechanism of high strain rate dynamic plastic deformation of materials treated by laser shock.
... The tensile stresses on EDM are explained by the thermal effects and consequently the phase transformations (white layer) during the machining [26,40]. The predominance of mechanical effects generates compressive residual stress, similar to that on milling specimens [1]. ...
In mould manufacturing the most representative component is the cavity, which can represent up to 75% of the total cost of the tooling and can reach 40% of manufacture time. In regions with small sizes and area with difficulty access to the cutting tool with "common"size (>2mm).These areas have been machined by EDM which has a negative impact over the cost and time of manufacture of the mould cavity. Therefore, surveys are developed in order to reduce the use of EDM in industry; among the alternatives, the micromilling process, using high-frequency spindle together with cutting tools smaller than 1 mm of diameter in HSM machine has been emerging as an option for machining small regions in dies and moulds. This book contains the results of the comparison between EDM and micromilling process applied to the mould industry.Machining experiments were carried out on AISI P20 and AISI H13 steels. Residual stress on machined surface, surface finishing, SEM images, microstructure and microhardness and additionally, an analysis of time and cost of manufacturing were carried out. The milling time was approximately 5 times lower than EDM one and generated a savings of 46% in the manufacturing.
... The main factors affecting the reliability of hard machining are surface integrity and tool wear. The prediction of surface and subsurface alterations and tool life is a challenging task in hard machining [1][2][3]. ...
Abstract: This paper presents results of an experimental investigation of turning of hardened
AISI H13 die steel, focusing on the effect of cutting parameters on work surface integrity.
The experiments were performed under dry cutting conditions using multilayer (TiN/MT
TiCN/Al2O3) coated carbide tools. Surface integrity parameters like, surface and subsurface
alterations and through thickness residual stresses were investigated to establish the effects
of dry cutting on the surface integrity of the machined component. Surface and subsurface
deformation were examined using a scanning electron microscope (SEM) and the residual
stress distributions by X-ray diffraction technique. Various forms of surface damages were
observed under different cutting conditions. The results obtained from surface examination
showed a strong correlation between cutting conditions and surface integrity. A microstructural
analysis shows the formation of a thin white layer less than 3~4 μm and severe plastic
deformations beneath the machined surface. The favorable compressive residual stresses
were obtained at low cutting speed with high feed rate and depth of cut. A wide range of
residual stress distributions beneath the machined surface were obtained depending on the
cutting conditions.
... Dahlman et al. [14] reported that the rake angle and feed strongly influence residual stresses despite an insignificant effect of cutting depth on residual stresses. Results obtained by Abrão and Aspinwall [15] showed that hard turning induces higher compressive residual stresses when compared to grinding. There thus exists an optimal combination of tool geometry, workpiece hardness and cutting conditions that can increase compressive residual stresses in both the axial and circumferential directions [16]. ...
The high cycle constant stress amplitude fatigue performance of metal matrix composite (MMC) components machined by a milling process was investigated in this study as a function of machining speed, feed rate and reinforcement particle size. The presence of reinforcement and particle size were found to be the most influential factors that affected the fatigue life. In contrast to this, the effect of feed and speed on tool-particle interaction, strain hardening and heat generation during milling of MMCs were balanced in such a way that the contributions of feed and speed on fatigue life were negligible. The interactions of different parameters contributed significantly to the fatigue life which indicated that the modelling of fatigue life based on these three parameters was relatively complex. The fatigue life of the machined MMC samples increased with decreasing particle size and increasing feed. However, the fatigue life was not influenced by speed variation. The presence of smaller or no particles induced a complete separation of failed samples, in contrast to that of specimens containing larger reinforcing particles where crack growth was arrested or deflected by the reinforcing particles.
... Recently, several studies have been published on the surface integrity of bearing steel after grinding, and some of the obtained results might proof valuable for optimizing the grinding of bearing raceways [2][3][4]. For instance, some scientists studied the surface integrity of bearing steel after grinding the steel using a CBN grinding wheel, as well as the surface integrity of bearing steel after hard turning, and then compared the surface integrity of the bearing steel after the two different processes. ...
To improve the grinding process towards a higher surface integrity, in this study, an orthogonal test was designed and conducted to determine the effect of the wheel speed, workpiece speed, and the grinding depth on the surface integrity of a bearing raceway. After the grinding process, the residual stress, the residual austenite content, the surface hardness, the thickness of the affected layer, the surface roughness, and other properties were measured, and a parametric characterization of the surface integrity of the raceway was performed. Using the results of the orthogonal test as training samples, two support vector machine (SVM) models were established, and the prediction accuracy was tested through cross-validation. Finally, the step size search method was used starting at the optimal grinding parameters obtained through the orthogonal test, and the grinding parameters were further optimized using the two SVM models. The results showed that combining an orthogonal test with an SVM model can effectively shorten the time required for optimizing the grinding process, and that a global optimum can be obtained for the surface integrity.
... Thus, the residual stress and the scratches induced by the machining process are widely investigated [1][2][3][4][5]. Schwach and Guo [6] conducted a series of rolling contact fatigue tests for hard turned AISI 52100 steel components, and the effects of the process-induced residual stress profile and the white layer on rolling contact fatigue were investigated. ...
Surface scratches and residual stresses inevitably appear on the surface of the component as a result of the machining process. The damage evolution of surface scratch due to the combined effect of cyclic loading and residual stresses will be significantly different from the case where only the cyclic loading is considered. In the damage evolution of surface scratch, the short crack growth is of great importance owing to its apparently anomalous behaviors compared with the long-crack growth. In this paper, the effect of the surface roughness and the residual stress on the short crack growth is studied. Firstly, the surface roughness and the residual stress of 7075-T6 aluminum alloy induced by the high speed milling process with various cutting speeds and feed rates are investigated with the experimental method. The maximum height roughness parameter is measured, which is regarded as the surface defect induced by the milling process. The residual stress on the specimen surface is measured with the X-ray diffraction. Results show that the surface roughness becomes higher with the increase of the feed rate. However, the influence of the cutting speed on the surface roughness is not significant. The residual stresses on the specimen surface are all in the compressive state. The residual stress is more compressive as the feed rate increases. The effects of the process parameters on the surface roughness and the residual stress are described by the fitted formulas. Then a modified model is built to characterize short fatigue crack growth behaviors with the consideration of the residual stress. This model is proved to provide a realistic treatment of the short crack growth, as reflected by comparison with experimental fatigue crack growth data of medium carbon steel and 7075-T6 aluminum alloy published in literature. The effect of surface roughness and residual stress caused by the milling process on the short crack growth is also investigated by using the proposed model. The growth of the scratch is nonlinear when it is subjected to the cyclic load. The compressive residual stress reduces the growth rate of the crack. The crack with larger initial surface roughness grows faster than that with smaller roughness. The correlation of surface roughness, residual stress and crack growth length is obtained by the polynomial fitting. The investigations in this paper can help the damage tolerance design of structures and improve the awareness of the effect of the residual stress and surface roughness induced by the machining process on the short crack growth.
Copyright © 2016 by ASME Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
... This wiper modified insert can increase feed rate twice while maintaining the same surface roughness or can reduce surface roughness by half while maintaining the same feed rate when compared to the machined surface by using conventional insert [4][5][6]. In this way, the machined surfaces with wiper inserts are comparable to those obtained by grinding, hence turning process with wiper insert can eliminate the need for further finish machining operations [7][8][9]. ...
Wiper insert have the characteristics of achieving an excellent surface finish and improving the productivity in turning processes. Wiper insert can provide twice feed rate while maintaining the comparable surface roughness compared to that provided by the conventional insert. In the present study, surface topographies in finish turning with conventional and wiper inserts are investigated. The key element of this work is that the cutting edge path equation in the cutting tool coordinate system is transformed into the machine tool and workpiece coordinate system by the use of spatial coordinate transformation. Following that a surface topography simulation algorithm based on the cutting edge path equation and cutting parameters is put forward. The output of this work is that both the simulated surface topography and surface roughness profile are good agreement with the experimental results. Both the simulated and the actual machined surface results show that better surface topography is obtained in finish turning with the wiper insert than that with conventional insert. Burnishing effect of the wiper insert leads to half decrease of the Ra and Rz. The actual surface profiles are no longer regular wave shapes due to ploughing effect and side flow existing in the cutting zone. In addition, a surface roughness map has also been developed to optimize the selection of wiper radius and feed rate to satisfy the requirement of surface finishing with higher productivity. From the viewpoint of cutting tool design, the wiper radius with five times larger than tool nose radius can fully come into its role. This provides a novel insight into the design of wiper insert over conventional techniques. Above all, the proposed model gives a better prediction of surface roughness in finish turning process compared to the previous empirical and regression roughness models. The prediction of surface roughness in finish turning with wiper insert is also realized.
... If the load is too high, seizure will occur, but if all of these are avoided then the only alternative and viable cause of failure is due to the continuous accumulation of residual stress until spalling occurs. Such accumulation can be further enhanced by plastic deformation and strain or stress-induced phase transformations due to service load [38][39][40]. ...
Whereas considerable progress has been reported on the quantitative estimation of the microstructure of steels as a function of most of the important determining variables, it remains the case that it is impossible to calculate all but the simplest of mechanical properties given
a comprehensive description of the structure at all conceivable scales.
Properties which are important but fall into this category are impact
toughness, fatigue, creep and combinations of these phenomena.
The work presented in this thesis is an attempt to progress in this
area of complex mechanical properties in the context of steels, although
the outcomes may be more widely applied. The approach used relies
on the creation of physically meaningful models based on the neural
network and genetic programming techniques.
It appears that the hot–strength, of ferritic steels used in the power
plant industry, diminishes in concert with the dependence of solid solution strengthening on temperature, until a critical temperature is
reached where it is believed that climb processes begin to contribute. It
is demonstrated that in this latter regime, the slope of the hot–strength
versus temperature plot is identical to that of creep rupture–strength
versus temperature. This significant outcome can help dramatically
reduce the requirement for expensive creep testing.
Similarly, a model created to estimate the fatigue crack growth rates
for a wide range of ferritic and austenitic steels on the basis of static
mechanical data has the remarkable outcome that it applies without
modification to nickel based superalloys and titanium alloys. It has
therefore been possible to estimate blindly the fatigue performance of
alloys whose chemical composition is not known.
Residual stress is a very complex phenomenon especially in bearings due to the Hertzian contact which takes place. A model has been
developed that is able to quantify the residual stress distribution, under
the raceway of martensitic ball bearings, using the running conditions.
It is evident that a well–formulated neural network model can not only be extrapolated even beyond material type, but can reveal physical relationships which are found to be informative and useful in practice.
... However, a thick white layer can be produced in grinding under certain conditions [5]. Abrào et al. [6] showed that the assessment of the fatigue life of turned and ground hardened bearing steel indicated that superior fatigue strength was obtained with turned specimens. Konig et al. [7] compared the properties of ground and hard turned workpiece surface zones and the results showed that the formation of a so-called 'soft skin' is largely suppressed in hard turning operations due to the stress-induced hardening of the workpiece material. ...
The aim of this work is to investigate the residual stress changes induced by dry orthogonal machining of induction surface hardened AISI 4340 steel (58-60 HRC). The machining operations were performed using mixed ceramic inserts. Residual stresses were measured using the X-ray diffraction method and the effects of cutting parameters on the residual stresses are investigated in this work. It was found that dry hard machining induces a compressive residual stress state on the surface and below the machined surface. The residual stress distribution is significantly affected by the cutting feed and the cutting speed. When the cutting feed is increased, the compressive surface residual stresses, the maximum compressive peak and the area of the compressive zone are increased too. However, surface residual stress tends to be tensile when the cutting speed is increased. A thin white layer was observed at a high cutting speed and feed. These results show that hard machining process may be an alternative to grinding since an enhanced surface integrity in terms of residual stresses can be achieved.
... Several techniques have been developed in order to estimate, qualitatively and quantitatively, the extent of the influence of the machining process and parameters on the properties and service life of the component. Compressive residual stress distributions were recorded when turning hardened bearing steel, the magnitude and penetration depth of these stresses were much higher when turning using worn inserts compared to new cutting tools [2]. Jeelani [3] showed the effect of cutting speed and tool rake angle on the fatigue life of aluminum alloy compared with the case of the virgin material. ...
Sert tornalama, sertlik değeri 45 HRC’nin üzerinde olan ancak daha çok 58-68 HRC aralığında olan silindirik parçaların üzerinden tek noktalı kesici bir uç ile talaş kaldırılması işlemidir. Makine parçalarında yüzey aşınma direncini artırmak için uzun süredir sertleştirilmiş çelikler tercih edilmektedir. Günümüze kadar sertleştirilmiş çelik yüzeylerinin bitirme işleminde kullanılan taşlamanın yerini şimdi sert tornalama işlemi almaya başlamıştır. Taşlamaya göre birçok avantaja sahip olan sert tornalama temel olarak geleneksel tornalamadan farklı olup, başarılı bir proses, tüm sisteme bağlıdır. Sert tornalama işleminde yüksek dinamik rijitliğe sahip olması gerekli tezgâh ve kesici takım, daha büyük kuvvetlere ve daha yüksek sıcaklıklara dayanacak şekilde tasarlanmalıdır. Yarı ince işleme veya bitirme işlemi olan sert tornalamada yüzey kalitesi büyük önem taşır. Yüzey kalitesi, hem kesme kararsızlığının hem de takım-iş parçası yükleme koşulunun bir sonucudur. Genelde sert tornalama işlemlerinde düşük maliyetli kaplamalı karbür takımların yanında, CBN/PCBN ve seramik kesiciler gibi yüksek aşınma direnci ve yüksek sertliğe sahip takımlar kullanılır. Süper sert malzemelerdeki gelişmeler sonucu, CBN ve PCBN kesiciler sert tornalamada önemli rol oynamaktadırlar. Sert tornalama, esneklik ve konvansiyonel taşlamaya kıyasla daha kısa ayar süreleri nedeniyle uygun maliyetli olduğu kanıtlanmıştır. Taşlamanın gerektirdiği maliyetli form taşlarına ihtiyaç duyulmadan karmaşık konturlar kolayca işlenebilir ve birden fazla işlemin tek bir ayar ile işlenmesi mümkün olur. Küçük partiler veya özel parçalar üretilirken önemli bir avantaja sahip olan sert tornalama işleminde, yüksek talaş kaldırma oranlarında da iyi veya daha iyi yüzey kalitesi sağlanabilmektedir. Genelde kuru şartlarda yapılan sert tornalama işlemi soğutma sıvısı gerektirmediğinden, çevre dostu bir işlemdir. Her geçen gün talaşlı imalat endüstrisinde yaygınlaşan proses ile ilgili olarak, beyaz tabaka oluşumunu kontrol etme, takım tezgahı dinamik rijitliğini iyileştirme ve kombine tezgah tasarımı, efektif soğutma yöntemi ve işlemi iyileştirme araştırmaları devam etmektedir. Başarılı araştırmalar, hali hazırda etkili olan bu işlemin tercih edilirliğini artıracaktır.
Beyaz tabaka, bir metalin tane yapısının son derece rafine olduğu mikro-yapısal bir durumdur. Metalik malzemelerde dağlamaya direnen ve mikroskop altında özelliksiz ve beyaz görünen sert malzeme tabakalarını ifade eder. Birçok araştırmacı tarafından çeliklerdeki beyaz tabaka oluşumunun martenzitik faz dönüşümünden kaynaklandığı sonucuna varılmıştır. Talaşlı imalat işlemlerinde beyaz tabaka oluşumunu etkileyen, termal ve mekanik iki mekanizma vardır. Yüksek kesme hızlarında beyaz tabaka oluşumunun öncelikle termal olarak indüklenen martenzitik faz dönüşümünden kaynaklandığı, düşük ve orta kesme hızlarında ise dönüşüme mekanik etkilerin baskın olduğu aşırı plastik deformasyonun indüklediği tane inceltme mekanizmasının hâkim olduğu sonucuna varılmıştır. Özellikle agresif işleme parametreleri uygulandığında veya aşınmış bir kesici takım kullanıldığında işlenmiş parça yüzeylerinde beyaz tabaka meydana gelir. Talaşlı imalat işlemlerinde, kesici takımdaki tedrici yan yüzey aşınması sonucu yükselen sıcaklık nedeniyle beyaz tabaka kalınlığı artarken, artan takım aşınması ile işlenen yüzeyde çekme tipi kalıntı gerilmeler meydana gelir. Genelde beyaz tabakalar yüzeyde çekme tipi kalıntı gerilme içerirken, gerilmenin durumu yüzey-altında derine indikçe basma tipi haline gelir. Proses kaynaklı beyaz katman, komponentin yorulma dayanımı ve servis performansında, istenmeyen önemli değişikliklere yol açar. Çünkü işlenen yüzeydeki çekme gerilmesi, yorulma çatlaklarının başlamasını teşvik ederken, basma gerilmeleri bu çatlakların başlamasını ve ilerlemesini engeller. Yüzeyde beyaz tabakası olan numunelerin beyaz tabakası olmayanlara göre ortalama 7 kat daha kısa ömre sahip olduğu bildirilmiştir. Diğer yandan bazı araştırmacılara göre, beyaz tabakanın yorulma mukavemeti üzerinde önemli bir etkisi yoktur, ancak zararlı olan işlenmiş yüzey üzerindeki kalıntı gerilmelerdir. Beyaz tabaka oluşumunun sebebi konusunda değişik öneriler olmasına rağmen sorun tam olarak anlaşılmadığından daha fazla çalışma ve literatür incelemesi, bu karmaşık durumu netleştirmeye yardımcı olacaktır.
Grinding is considered as a rather environmental-unfriendly process, where the aspects involving the high demanding process energy input and required fluid application can lead to severe environmental impacts while achieving high product quality. However, the reduction of the cutting fluids raises the cutting temperature, leading to negative alterations of the ground subsurface. Such detrimental aspects are usually not factored into a life cycle inventory analysis. Therefore, this study introduces a new sustainability indicator based on the rolling contact fatigue life of the component, as determined by the grinding process. A method for calculating this indicator is presented, and a case study is illustrated. The subsurface damage thickness can be loosely correlated with fatigue life aThe authors would like to thank the Braziliannd introduced as a new indicator. The selected indicators were used as decision-making parameters to showcase the potential of the product life factor as an aggregate sustainability indicator.
ÖNSÖZ
Mühendislik alanında gerçekleşen teknolojik ilerlemeler hızlı art�maktadır. Ulusal ve Uluslararası nitelikte faaliyetlerle oldukça prestij
kazanmış olan Güven Plus Grup A.Ş. Yayınları tarafından çıkarılan bu
kitap, “Malzeme Teknolojisi ve Tasarım Bilimlerine Yeni Yaklaşımlar”,
adıyla çeşitli konuları ele alan, birçok deneysel ve teorik çalışma, analiz
ve değerlendirmeleri kapsayan on sekiz farklı bölümden oluşmaktadır.
Kaynağından son kullanımına kadar bor mineralleri, karbon nano�tüp katkisinin karbon fiber takviyeli polimer matrisli kompozitlerin mekanik özellikleri üzerine etkisi, implant malzemesi östenitik paslanmaz
çeliklerde yüzey bütünlüğünün korozyon dayanımına etkisi, Al7075
alaşimina uygulanan ısıl işlemindeki son gelişmeler, polimerlerin tribo�lojik davranişlarinin tahmini analizi vb. daha pek çok önemli konuda
araştırmalar ve deneysel çalışmaları bulacaksınız. Kitapta yer alan her
bir bölüm değerli akademisyenlerin, araştırmacıların titizlikle ortaya
koyduğu özgün çalışmalardan oluşmaktadır.
Mühendislik teknolojilerinin birçok ilgi çekici konularına değinilen
bölümlerin yer aldığı kitap, sayısız araştırmacının akademik çalışmaları�na ışık tutacaktır. Gerek Yüksek Öğretim Kurumu (YÖK) kataloglarında
gerek kamu kurumu kütüphanelerinde, gerekse kişisel arşivlerde oldukça
değerli bir yer bulacaktır.
Bu eserin gerçekleşmesinde; emeği geçen saygı değer yazarlarımıza,
hakemlerimize, teknik ekibe ve kitabımızı edinen siz sevgili okurlarımı�za teşekkürlerimizi sunarız.
Prof. Dr. Yusuf ŞAHİN
Dr. Öğr. Üyesi Senai YALÇINKAYA
Aralık 2021
Machined surface integrity of bearing rings is often the main concern for the bearing manufacturers as it affects their fatigue life. The present study investigates the surface integrity of AISI 52100 bearing rings finished by precision hard turning and grinding and its influence on fatigue life. A twin-disk machine is used to evaluate the RCF life. As main results, precision hard turning can achieve low surface roughness 0.1 μm Ra with respect to the required 0.2 μm Ra obtained by grinding. Both processes introduce microstructural changes. At subsurface, precision hard turning induces subsurface compressive and maximum residual stresses at 10–50 μm depth, corresponding to the transition zone formed after a thin white layer (<1 μm); however, grinding induces tensile residual stresses from 15 μm depth, corresponding to the bulk material. The residual stresses measured during RCF test (after running-in process and after spalling) of ground ring specimens exhibit peak compressive value in subsurface from 140 μm depth. The ring specimens machined by precision hard turning have fatigue life four times higher than those machined by grinding. This enhancement of RCF life is due to the low roughness reached and also to the subsurface compressive residual stresses at shallow depth before RCF test.
Superalloys are required to withstand higher stresses and operating temperatures to meet the current demands for increased gas-turbine efficiency and superior damage tolerance. The challenges imposed on the service performance improvement not only relate to the bulk microstructure, but also to microstructures altered by post-processing technologies such as laser shock processing (LSP). For the application of LSP, some existing problems still need to be solved till now. Some related issues of the microscopic surface topography evolution induced by laser shock treatment lack attentions, and the application of LSP on superalloys is rarely reported, especially for single crystal superalloys. Given that, the aim of this study is to investigate the effect of laser shock treatment on surface topography, microstructure and mechanical behaviors of superalloys.
The effect of laser shock treatment on surface topography evolution of a Ni-based single crystal superalloy was investigated. The surface topographies before and after laser shock treatment were examined by non-contact white-light interferometer (WLI). The results showed that, by taking advantage of WLI, the shrinkage porosities and the interdendritic structures were observed simultaneously. With the increasing impact times, the circle pit induced by laser shock became deeper. The nano-scale surface reliefs were found on the bottom of circle pit induced by LSP, and the specific plastic flow of metallic materials under the action of compressive stresses was deemed as the primary contributor to the formation of surface reliefs.
Surface topography of an upsetting wrought superalloy processed by laser shock treatment was observed in microscale and a series of morphological characteristics such as surface reliefs with special orientation, destructive dimples were found. The longitudinal sizes of the micro surface structures were within 100 nm to 1000 nm generally. It can be concluded that the formation of surface reliefs was a release way of the internal stresses under laser shock and small dimples were deemed as an external representation of the release of impact energy in the mode of fracture damage.
A striking phenomenon was found that local plastic deformations with an opposite direction to the external force applied on metallic target surface under a given laser shock condition. Laser shock treatment was carried out on a number of metallic materials, and the surface topographies after laser shock treatment were observed. The results showed that many surface relief structures with irregular shapes and random distributions appeared on target surfaces under the action of invisible shock waves. It personified the real plastic flow behavior of metallic materials suffered to pressure waves, and the local reverse deformation.
Nanoindention tests and scanning electron microscopy (SEM) microstructure observations were conducted on the experimental Ni-based single crystal superalloy after LSP treatment. Distinct surface hardening behavior was found to occur under the selected LSP technology. A large discrepancy in γʹ areas happened on laser shocked regions and the large plastic deformation embodied in γʹ phases’ deformation brought a significant hardening effect.
The tensile deformation behavior of the Ni-based single crystal superalloy was also investigated, both in virgin condition and after LSP treatment with varied technology parameters. Stress-strain curves of tensile specimens were analyzed. Microstructural observations of the fracture surface and the longitudinal cross-sections of ruptured specimens were performed additionally in an effort to clarify the fracture mechanisms. The results showed that the formation of surface hardening layer had not affected the yield strength. Furthermore, fundamental differences in the plastic responses at different temperatures due to LSP treatment had been discovered. At 700℃, the crack propagation was held back when it extended to the surface hardening layer and the ensuing slip steps improved the plasticity. However, at 1000℃, surface hardening layer hindered the macro necking, which resulted in the relatively lower plasticity.
High cycle fatigue testing was conducted on the single crystal superalloys. Distinct cracking behaviors were found to occur to specimens treated by different LSP technologies. A crack generally initiated from the casting micropore. For the well surface strengthened specimens suffered great laser shock intensities, the crack initially grew along one or more of the {111} planes and fell on the edge of the cylindrical specimen. For the poorly-strengthened specimens, the final fracture area was located inside or disappears.
Advanced manufacturing technologies are based on-time-delivery principles. The customer requirements regarding quality, cost and delivery terms become more and more important , both for supplier and sub-supplier. Taking into account these considerations, all companies started the implementation of some new strategies and technologies based on continuous improvement principle. One of these is hard turning, as a cost efficient alternative to grinding. The technology is analyzed in the case of a bearing component, as a new process step versus the existing grinding process. Experimental tests were performed in order to describe the advantages of this technology. Cubic Boron Nitride grades (CBN) are used for cutting. The main influence of this technology in process flow is analyzed from different approaches. Experimental results were analyzed in terms of the ring surface quality, roughness and profile, and also on process time and production cost.
This study investigates the influence of the rake angle on the surface integrity and fatigue performance of hard machined surfaces. The results demonstrate that a higher rake angle induces more compressive residual stresses and a more softened layer. Changing the rake angle was found to increase the crack initiation life up to 104% and crack propagation life up to 256%. Consequently, changing the rake angle increased the fatigue life up to 224%. The fatigue tests demonstrated that the rake angle has a significant influence on the fatigue life and that the effect is further increased if the loading is reduced.
This study presents a experimental investigation to clarify the effects of tool nose radius and tool wear on residual stress distribution in hard turning of bearing steel JIS SUJ2. Three types of CBN tools with different nose radius (0.4, 0.8 and 1.2 mm) were used in this study. The residual stresses beneath the machined surface were measured using X-ray diffraction technique and electro-polishing technique. The results obtained in this study show that the tool nose radius affects the residual stress distribution significantly. Especially the effect on the residual stresses at the machined surface at early stage of cutting process is remarkable. For the tool wear, as the tool wear increases, the residual stress at the machined surface shifts to tensile stress range and the residual compressive stress beneath the machined surface increases greatly.
The hardness of hardened steel is one of the key characters of workpiece surface morphology. This paper focus on the instantaneous cutting layer parameters and cutting force under different hardness conditions. Based on the concept of centrifugal force vibration and tool error, the amendatory vibration model of cutting force in milling hardened steels with high speed is established to analyze the influence on the tools vibration characteristics and surface morphology in surface hardness distribution. Through the experiment and simulation, we find the regular pattern that surface hardness distribution influence on vibration and surface morphology. The cutting conditions are also determined for the high-speed milling process, to reach the acquirement of cutting stability and surface morphology on the surface of hardened steel.
In the technological planning of hard machining procedures, several factors of the component have to be considered. One factor is the system of geometrical dimensions of the components. The potential procedures capable of providing the required accuracy and quality specified to the surfaces, and/or their (economical) efficiency can also be influenced by the geometrical dimensions. Beyond the generally prevailing time study, in the present paper the material removal rate and the surface rate are investigated referring to hardened internal cylindrical surfaces. These parameters are referred to the unit operation time. The values of the parameters are analysed at different bore geometries. The investigations are performed for hard machining procedures with different inserts, as well as a combined hard machining and grinding procedure, and values are given with conventional (traverse) grinding as the basis of the comparison.
A smooth particle hydrodynamic (SPH)-based scratch model was proposed to study the influences of residual stress induced by the first cutting on subsequent scratch. In this paper, comparisons were made between the results of only scratching the specimen and those of subsequent scratching the specimen after cutting under different scratch depths. Chip formation, scratching forces and residual stress in scratching-induced subsurface were recorded on oxygen-free high-conductivity copper (OFHC) during the simulations. Simulation results indicated that the first cutting produced work hardening in the subsurface of the specimen and the increased hardness led to a thinner and more curled chip. Meanwhile, the minimum chip thickness also decreased because of residual stress induced by cutting. Moreover, it also resulted in high resistance during the subsequent scratch so that the scratched surface presented flat. However, the material on both the sides of the groove bulged in Scratch model. Therefore, scratch after cutting is beneficial to obtain scratched surface with high quality.
Preparation methods of polycrystalline cubic boron nitride (PCBN) and its compact, as well as industrial application, were summarized. The sintered-type, growth-type and growth-sintered preparation of PCBN were discussed. Direct conversion method, brazing method and once sintering method in preparation of PCBN compact were compared. PCBN application in automobile, bearings, tools and other industries were reviewed. Finally, the future development trend of PCBN and PCBN compact was prospected. ©, 2015, Zhengzhou Institute of Abrasives Grinding. All right reserved.
This chapter presents an “overview” of residual stresses and microstructural modifications in surface layers. Surface alterations may include mechanical, metallurgical, chemical and other changes in workpieces by machining. The applications of some of these concepts in turning, milling and grinding are discussed in this chapter.
Increasing demand for precision components made of hard and brittle materials such as glasses, steel alloys and advanced ceramics, is such that conventional grinding and polishing techniques can no longer meet the requirements of today's precision manufacturing engineering. Particularly, in order to undertake micro-milling of optical glasses or other hard-machining materials, vibration assisted machining techniques have been adopted. However, it is essential and much needed to undertake such processes based on a scientific approach, i.e. the process to be quantitatively controlled and optimized rather than carried out with a trial-and-error manner.
In this research, theoretical modelling and instrumental implementation issues for vibration assisted micro-milling are presented and explored in depth. The modelling is focused on
establishing the scientific relationship between the process variables such as vibration frequency, vibration amplitude, feedrate and spindle speed while taking into account machine dynamics effect and the outcomes such as surface roughness generated, tool wear and material removal rate in the process.
The machine dynamics has been investigated including a static analysis, machine tool-loop stiffness, modal analysis, frequency response function, etc, carried out for both the machine structure and the piezo-actuator device. The instrumentation implementation mainly includes the design of the desktop vibration assisted machining system and its control system. The machining system consists of a piezo-driven XY stage, air bearing spindle, jig, workpiece holder, PI slideway, manual slideway and solid metal table to improve the system stability. The control system is developed using LabVIEW 7.1 programming. The control algorithms are developed based on theoretical models developed by the author.
The process optimisation of vibration assisted micro-milling has been studied by using design and analysis of experiment (DOE) approach. Regression analysis, analysis of variance (ANOVA), Taguchi method and Response Surface Methodology (RSM) have been chosen to perform this study. The effects of cutting parameters are evaluated and the optimal cutting conditions are determined. The interaction of cutting parameters is established to illustrate the intrinsic relationship between cutting parameters and surface roughness, tool wear and material removal rate. The predicted results are confirmed by validation experimental cutting trials.
This research project has led to the following contribution to knowledge:
(1) Development of a prototype desktop vibration assisted micro-milling machine.
(2) Development of theoretical models that can predict the surface finish, tool wear and
material removal rate quantitatively.
(3) Establishing in depth knowledge on the use of vibration assisted machining principles.
(4) Optimisation of cutting process parameters and conditions through simulations and
machining trials for through investigation of vibration assisted machining.
The effect of two finishing processes, namely, cutting and grinding, on the fatigue strength of hardened AISI 4340 steel was investigated. Three sets of flat tensile specimens were prepared by first machining into the general shape of the fatigue specimen standard, then they were hardened to HRC 54. The final grinding was carefully performed on one set of specimens. Two sets of specimens were fly cut to obtain a surface finish comparable to the ground surface. The residual stress distribution, surface structure, and surface profiles were determined. Fatigue testing was accomplished on these specimens in tension under load control. All the residual stress patterns were compressive, but the residual stress created byfly cutting reached a much deeper layer than that created by grinding. Fly cutting also produced a surface with a higher fatigue strength than the grinding did.
Tool life data are presented for various grades of conventional ceramic and PCBN cutting tool materials when turning hardened AISI H13 hot work die steel (52 HRC) and hardened AISI E52100 bearing steel (62 HRC). The paper also details some aspects of workpiece surface integrity following roughing and finishing operations. These include 3D mapping of surface texture and analysis of microstructure and microhardness variation. The results indicate that when machining the hot work die steel and finishing the bearing steel low concentration PCBN and mixed alumina tooling provide the longest tool lives.
Polycrystalline cubic boron nitride (PCBN) and oxide ceramics are at present the most efficient cutting tool materials for turning hardened and heat-treated steels. Their performance is characterised by specific differences. Comparative machining tests were carried out on heat-treated roller bearing steel to determine the fundamental areas of application. The Machine Tool Laboratory of RWTH Aachen has performed comparative turning tests on a range of steels, including 100 CrMo 7 3 roller bearing steel heat-treated to 60 HRC, with the aim of defining the respective capabilities of solid PCBN and oxide ceramic cutting tool materials. It was shown that, for rough machining, Amborite solid PCBN is superior because of its greater toughness. This superior performance is particularly noteworthy with interrupted cuts, repeated engagement of the work, and machining with high feed rates.
Steel workpieces of hardness in excess of 60 HRC and with different structures, depending on heat treatment, are very difficult to machine with conventional cutting tools. Tests at RWTH Aachen in Germany have shown the capabilities, advantages and present limitations of various cutting tool materials for the fine turning and drilling of hardened workpieces.
There is a great demand for informations about the functional behaviour of technical surfaces dependent from machininq processes. Thermal, mechanical and chemical influences determine the relevant physical properties of the surface. Besides metallographical methods and microprobe analysis, microhardness and residual stress measurements are suitable tools to investigate the physical state of surface layers. It is reported about the fundamentals of these techniques, their experimental execution and the accuracy to be expected. The combined application offers the determination of causes for the generation of the surface state which are thermal or mechanical induced plastic deformation, structural transformation, or chemical reaction.
This is the first of two articles on the subject of surface integrity of machined components. In this article the author examines the thermal, mechanical and environmental causes of damage found in machined surfaces and their effect on the mechanical properties of components. He describes microstructural changes, cracking, workpiece/environmental interactions and residual stresses which result from machining and the grinding process. The effects of these processes on steel and titanium alloys in particular are discussed. The second article will deal more fully with the effect of machining on subsurface residual stresses.
The first article on surface integrity which appeared in the February issue of the magazine described the deformation and microstructural changes which machining may induce in the surface of metal components. These changes may impair the surface properties and generally reduce the surface integrity of the finished component. In addition to the microstructural changes, residual stresses may also be generated at the surface. The formation of residual stresses and the effect of processing variables on them are described in this article. Remedies for thermal damage and methods of thermal damage/residual stress assessment are also considered.
The mechanical properties and the structural state of machined surfaces determine the functional behavior of components. The states of the surface-near zone, especially hardness- and residual stress distrubutions are influenced by machining parameters. Conventional testing methods such as metallographical inspection, x-ray diffraction, and hardness measurements are time consuming and cannot be used for real time testing. Therefore, there is a considerable need for nondestructive testing techniques. Beside the well known eddy current methods, ferromagnetic- and ultrasonic techniques can be used for measuring microstructure parameters and residual stresses. This paper focuses on state of the art of nondestructive procedures and discusses first application for the evaluation of the surface integrity. Refs.
The techniques for determining the surface and subsurface metallurgy characteristics of materials are reviewed and related to important properties such as distortion, static and dynamic strength, and stress corrosion.
AMBORITE PCBN cutting tool blanks have proved effective in the high volume removal rate machining of hard and abrasive ferrous materials such as alloy steels and cast iron. By the addition of other components, tool performance in fine cutting and finishing operations has been enhanced. Data is presented on the microstructure, indentation hardness (as a function of temperature and time) and wear of DBC50, compared with AMBORITE and AMBRAZITE.
Chip forming machining processes must be controlled to ensure the required surface finish and preserve optimum sub-surface microstructure with minimum residual stress in finished components. Laboratory techniques used to study these inter-related phenomena in a low-alloy steel are described.
This paper reports experimental measurements of the residual stresses in ground steel (1C-1·5Cr) specimens produced under ‘abusive’, ‘conventional’, and ‘gentle’ grinding conditions. Large tensile stresses are found in the abusively ground steel, but these can be completely removed by gentle grinding to a further depth of about 0·1 mm. Sparking out has little effect, and hand grinding is found to be of the abusive type.
Two well known forms of metallurgical damage of ground surfaces involve untempered and overtempered martensite. Both of these forms of metallurgical damage involve martensitic transformations. This paper reviews the nature of such transformations and the special characteristics that pertain in grinding where the time at temperature before quenching is unusually short.
MECHANICAL RESIDUAL STRESS IN A MACHINED SURFACE WAS STUDIED EXPERIMENTALLY. STRUCTURAL CHANGE WAS ELIMINATED BY MACHINING LOW-CARBON STEEL UNDER SELECTED CONDITIONS. THE SHAPE OFTHE CUTTING EDGE WAS FOUND TO GOVERN THE RESIDUAL STRESS NEAR THE MACHINED SURFACE WHILE THE LENGTH OF THE SHEAR PLANE WAS FOUND TO GOVERN THE BULK DISTRIBUTION OF THE STRESS. IT WAS ALSO FOUND THAT SMALLER DEPTH OF CUT DID NOT ALWAYS PRODUCE LOWER STRESSES. THE EFFECT OF THE DEGREE OF CONSTRAINT IN THE DEFORMATION PROCESS ON RESIDUAL STRESS FORMATION WAS DEMONSTRATED BY USING ORTHOGONAL, OBLIQUE, AND CONVENTIONAL CUTTING PROCESS. IT WAS OBSERVED THAT A LOWER DEGREE OF CONSTRAINT IN THE DEFORMATION PROCESS PRODUCED A LOWER LEVEL OF RESIDUAL STRESS.
This paper gives the investigation on surface integrity of grinding of hardened bearing steel GCr15 with resin bonded cubic boron-nitride (CBN) wheels. CBN wheels, when well dressed, offer significant advantages compared with aluminium oxide wheels, especially at high metal-removal rates. The compressive residual stresses are only produced when CBN wheels are used, the harmful tensile residual stresses are formed very easily with aluminium oxide wheels. However, CBN wheels after dressing with SiC stick cannot get a good result, serious thermal damage and big surface roughness are induced on the ground surface. Two new dressing techniques— elastic dressing and ultrasonic vibration dressing have been advanced, they are successful in well dressing CBN wheels and make the wheels have a strong cutting capacity to obtain higher ground surface integrity. Our experiments show that in dry grinding of bearing steel GCr15 with CBN wheels boronization takes place, it can increase wear-resistance of the ground surface about 30%.
The effect of high cutting speed and feed rate on the surface integrity of AISI 4340 steel during a finishing turning operation was investigated. The experimental work involved the determination of residual stress distribution in the surface region, microhardness variation of the surface region, and the examination of surface and subsurface using both optical and scanning electron microscopy. The residual stresses were found to be compressive. The microhardness in the surface region varied little and was the same as that of the bulk material. In general, the appearance of the surface was similar to those reported for low cutting speeds as recommended for machining the same type of steel.MST/998
This paper presents the results of an investigation of induced residual stress, induced strain, and induced subsurface energy in machined surfaces due to the machining process. The influence of tool wear on residual stress, strain, and energy is also reported. The exact elasticity solution for a split ring was extended and used to calculate the residual stress in the machined surface by using ring dimension changes caused by the electrochemical removal of a thin layer of residually stressed surface. The strain distribution beneath the machined surface was determined by using the grid technique. The subsurface energy stored in the machined surface was then obtained from the data of residual stress and strain. For the materials studied, this investigation showed that such energy could not be neglected when establishing the total energy needed for machining a unit volume of material.
Tool coatings having different surface roughness and tools having various magnitudes of flank wear were investigated. The experimental results show that tool wear is a dominant factor affecting the values of induced residual stress, strain, subsurface energy, and the quality of the machined surface. The increase of tool wear caused an increase of residual stress and strain beneath the machined surface. It was also found that the overall energy stored in the machined subsurface increases as the tool wear increases and as the tool surface gets rougher. When the cutting tool is severely worn, the machined surface not only becomes very rough, but also contains many partially fractured laps or cracks. This makes tool wear a key factor in controlling the quality of the machined surface.
The functional behaviour of a machined component is substantially determined by the physical state of its surface including the residual stress distribution near the surface. The necessity to come to more exact methods of layout for machined components compels one to take “surface integrity” as defined by M. Field /1/ and herewith residual stresses into consideration. Residual stresses directly influence the deformation of workpieces, their static and dynamic strength, and their chemical and electrical properties.According to the relevance of residual stresses generated by machining, several laboratories affiliated with CIRP worked on a cooperative investigation of measurement techniques to define the state of the art. Measurements of residual stress distributions generated by some important machining processes have been made. This paper gives a report and tries to show how the possible sources for development of residual stresses are involved.
Surface integrity of nm~hined components/ micro. structural aspects, Metals Muter Camme~ A review of measuring methods for anrfaceintegrity
- K M Nealley
- J Reld
- J Kahles
I] K. Nealley, Surface integrity of nm~hined components/ micro. structural aspects, Metals Muter,, (1988) 93-96. [2l M, Reld, J.E Kahles and J,T, Camme~ A review of measuring methods for anrfaceintegrity, Ann, CIRP, 21 {2) (1972) 219-238.
Surface inte~ty in turning high strength NCMV steel, Technical memorandum, CA
- D W Watson
D.W. Watson, Surface inte~ty in turning high strength NCMV steel, Technical memorandum, CA. Pmons & Co,, Newcastle upon Tyne, 1976, 29p.
Effect of glinding conditions and resultant residual stresses on the fatigue strength of hardened steel Surface integrity of machined components/ residual sh'esses and fatigue
- L P Tarasov
- W S Hyler
- H R Letner
L.P. Tarasov, W.S. Hyler end H.R. Letner, Effect of glinding conditions and resultant residual stresses on the fatigue strength of hardened steel, Proc. 16th Annual Meeling of the American Society for Testing and Materials, Vol. 57,1987, pp. 601-623, [24l K. Neaiiey, Surface integrity of machined components/ residual sh'esses and fatigue, Metals Mater., (1988) 141-145.
A study onthe residual stress disUribu~ons by tunfing
- K Tsuchida
- Y Kawada
- S Kndama
K. Tsuchida, Y. Kawada and S, Kndama, A study onthe residual stress disUribu~ons by tunfing, BulL Jap. Soc. Mech. Fa~g.,18 ( l l S ) (1975) 123-130.
Mechanical propeflles, microstmcture and wear of DBCS0, Ind. Diamond Rev Tool life and surface integrity evaluations when machining hardened AISI HI3 eJmd AISI E52100 steels with conventional ceramic and F~N tool materials
- M Hoofer
- Li Shakib
- A Pant
- C A Bnx~kes
R,M. HooFer, LI. Shakib, A. Pant and C.A. Bnx~kes, Mechanical propeflles, microstmcture and wear of DBCS0, Ind. Diamond Rev.. 4 (1989) 170-173. 127l A.M. Abrlo, D.K. Aspinwall and M.H.L Wise, Tool life and surface integrity evaluations when machining hardened AISI HI3 eJmd AISI E52100 steels with conventional ceramic and F~N tool materials, SME Tec~mical paper nuraber MR95-159,1995.
Residual stw~ses of hem treated steels with different hardness after grinding with cubic bm'on nit.ri~ (C~N)
- R Henog
- A Sollich
- H Wohlfahrt
R. Henog, A. Sollich and H. Wohlfahrt, Residual stw~ses of hem treated steels with different hardness after grinding with cubic bm'on nit.ri~ (C~N), Int. Conf. on Resid~al Stresses ICR52, Nancy, France.
Measurement of residual sw~sses by the hole drilling strain range method
- Measmements Inc
Measmements Group Inc., Measurement of residual sw~sses by the hole drilling strain range method, TN403-3 { 1988).
Fine turning and drilling hardened steels, ln~ Diamond Rev Turning bearing steel with amborite and eern¢
- M Ksnig
- R Iding
- Link
KSnig, M. Iding and R. Link. Fine turning and drilling hardened steels, ln~ Diamond Rev., 2 (1990) 79-85. [t4l W. K6nig and Th. Wand, Turning bearing steel with amborite and eern¢, ln~ Diamond Rev., 3 (1987) ! 17-120.
Morlo Dins and JL. Lebmn, Study ofmsidualstmsses and void working generated by machining of AIS! HI3 steel
- L Pina
L Prata Pina, A. Morlo Dins and JL. Lebmn, Study ofmsidualstmsses and void working generated by machining of AIS! HI3 steel, lnt Conf. on Residual stresses, ICRY2, Nancy, France.
A study on residual stresses and tool wear induced by machining processes, Trans, North American Manufact.ring Research Institution of SME
- Q Xie
- E Bayoemi
- A Ken~l
- G Sheldon
Q. Xie, E. Bayoemi, L,A, Ken~l, and G.L Sheldon, A study on residual stresses and tool wear induced by machining processes, Trans, North American Manufact.ring Research Institution of SME, 1989, Colmnb~, Ohio, pp. 170--174.
Effect of high cutting speed on surface integrity of AISI 4340 steel
- Sadat
Surface integrity in turning high strength NCMV steel
- Watson
Effect of grinding conditions and resultant residual stresses on the fatigue strength of hardened steel
- Tarasov
Fine turning and drilling hardened steels
- König
A study on the residual stress distributions by turning
- Tsuchida