Fig 1 - uploaded by D. Lung
Content may be subject to copyright.
Cross sections of the microstructure of (a) CW724R; (b) CW508L; (c) CW511L; (d) CW510L (A); (e) CW510L (W); (f) CW614N
Source publication
This paper deals with fundamental investigations on the machinability of lead-free brass alloys. The effect of microstructure and silicon as alloying element on chip formation, cutting forces, tool temperatures and tool wear is analyzed during external turning. Based on that, various approaches for machinability enhancement were investigated in ord...
Similar publications
Background/Objectives: Engine produces high amount of heat while running. This can raise the engine temperature to very high level and can damage or seize the engine components. Hence for the safety of engine components, it needs to run at much lower temperature, which is called engine working temperature. Methods/Statistical Analysis: Radiator pla...
This paper reports on the experimental investigation of the cooling effect harvested in liquefied petroleum gas (LPG)-fueled vehicles. The heat required to vaporize the LPG in a vaporizer, which was originally transferred by the engine coolant, was replaced by air flow. The fuel line was modified by adding an evaporator equipped with an expansion v...
Application of cutting fluid that provides both coolant and lubrication properties in manufacturing operations such as turning, milling, grinding and other processes has been proven to improve the machining output in many aspects. In cryogenic machining, liquid nitrogen (LN2) is used as cutting fluid to reduce the temperature generated at the cutti...
Since the inception of nuclear power as a commercial energy source, safety has been recognized as a prime consideration in the design, construction, operation, maintenance and decommissioning of nuclear power plants. The release of radioactivity to the environment requires the failure of multiple safety systems and the breach of three physical barr...
Citations
... While lead-free CuZn-alloys generally retain outstanding application properties, their machinability and also their cost-effectiveness in mass production can be classified as significantly worse. Non-breaking, long chips, high process forces, and higher tool wear are the results [1][2][3], which is why more and more approaches are being researched to optimize the machinability of lead-free CuZnalloys. However, it is not known how the targeted variation in the mechanical properties, microstructure, and chemical composition affects the chip formation of lead-free CuZnalloys and which mechanisms of action underlie the process. ...
... While machinability depends on the properties of the material as well as the selected process parameters and process boundary conditions, most studies have focused on optimizing machinability on the process side. For example, there is a large number of research papers that have dealt with the tool and process design for turning, drilling, or milling of lead-free CuZn-alloys [2,[4][5][6][7][8][9][10][11][12][13][14]. Consequently, there is a broad knowledge of how to adapt tools and processes for the machining of existing leadfree CuZn-alloys. ...
... In the past, scientific approaches to substituting lead with other elements that do not have the same harmful effects on health or the environment as lead have been researched. The elements investigated include bismuth [15,16], graphite [17,18], or silicon [2,[19][20][21]. So far, silicon has established itself as the only industrially relevant lead alternative with the aim of improving machinability. ...
... Studies of wear of cemented carbide by softer Cu and its alloys at moderate temperatures are scarce. The most commonly considered contact is turning, which generally takes place at much higher temperatures [2][3][4][5][6][7][8]. One reason for the frequent study of turning is the fact that reduction, or even omission, of Pd in Cu alloys, generally decreases the machinability [2][3][4][5]9]. ...
... The most commonly considered contact is turning, which generally takes place at much higher temperatures [2][3][4][5][6][7][8]. One reason for the frequent study of turning is the fact that reduction, or even omission, of Pd in Cu alloys, generally decreases the machinability [2][3][4][5]9]. The wear mechanism is not frequently studied in detail, but generally reported as abrasion [2,6], chemical diffusion (crater) wear [5,8] or oxidation-enhanced wear [7]. Abrasion, or scratching wear, is also suggested from wire drawing [10], blanking [11,12] and in a laboratory test, including reciprocating sliding by a cemented carbide ball against a Cu plate [13]. ...
... One reason for the frequent study of turning is the fact that reduction, or even omission, of Pd in Cu alloys, generally decreases the machinability [2][3][4][5]9]. The wear mechanism is not frequently studied in detail, but generally reported as abrasion [2,6], chemical diffusion (crater) wear [5,8] or oxidation-enhanced wear [7]. Abrasion, or scratching wear, is also suggested from wire drawing [10], blanking [11,12] and in a laboratory test, including reciprocating sliding by a cemented carbide ball against a Cu plate [13]. ...
... Copper and its alloys are frequently used for applications in electronic, automotive and sanitary industry. In these cost-sensitive [188][189][190][191] Chip formation largely depends on zinc content and phase composition [188][189][190][191] Described general disadvantages of very long chips (seeFig. 16) High chip compression [188][189][190][191] CuZn-Alloys with up to 37% Zinc consist purely of ductile α-CuZn phase [188][189][190][191] Limited productivity in highly automated machining Very long chips [188][189][190][191] More segmented chips (heterogeneous brass materials, high zinc contents up to m Zn = 42%) [188][189][190][191] Materials consist of a mixture of αand β-CuZn which increases hardness and tensile strength while reducing ductility [188][189][190][191] Chip segmentation / breakability improves with increasing contents of β-CuZn and rising tensile strengths [189][190][191][192] ...
... Copper and its alloys are frequently used for applications in electronic, automotive and sanitary industry. In these cost-sensitive [188][189][190][191] Chip formation largely depends on zinc content and phase composition [188][189][190][191] Described general disadvantages of very long chips (seeFig. 16) High chip compression [188][189][190][191] CuZn-Alloys with up to 37% Zinc consist purely of ductile α-CuZn phase [188][189][190][191] Limited productivity in highly automated machining Very long chips [188][189][190][191] More segmented chips (heterogeneous brass materials, high zinc contents up to m Zn = 42%) [188][189][190][191] Materials consist of a mixture of αand β-CuZn which increases hardness and tensile strength while reducing ductility [188][189][190][191] Chip segmentation / breakability improves with increasing contents of β-CuZn and rising tensile strengths [189][190][191][192] ...
... In these cost-sensitive [188][189][190][191] Chip formation largely depends on zinc content and phase composition [188][189][190][191] Described general disadvantages of very long chips (seeFig. 16) High chip compression [188][189][190][191] CuZn-Alloys with up to 37% Zinc consist purely of ductile α-CuZn phase [188][189][190][191] Limited productivity in highly automated machining Very long chips [188][189][190][191] More segmented chips (heterogeneous brass materials, high zinc contents up to m Zn = 42%) [188][189][190][191] Materials consist of a mixture of αand β-CuZn which increases hardness and tensile strength while reducing ductility [188][189][190][191] Chip segmentation / breakability improves with increasing contents of β-CuZn and rising tensile strengths [189][190][191][192] ...
Machinability is a generalized framework that attempts to quantify the response of a workpiece material to mechanical cutting, which has been developed as one of the key factors that drive the final selection of cutting parameters, tools, and coolant applications. Over the years, there are many attempts have been made to develop a standard evaluation method of machinability. However, due to the complexity of the influence factors, i.e., from work material and cutting tool to machine tool, that can affect the materials machinability, currently there is no uniquely defined quantification of machinability. As one of the outcomes from the CIRP's Collaborative Working Group on "Integrated Machining Performance for Assessment of Cutting Tools (IMPACT)", this paper conducts an extensive study to learn interacting machinability parameters to evaluate the overall machining performance. Specifically, attention is focused on recent advances made towards the determination of the machinability through tool wear, cutting force and temperature, chip form and breakability, as well as the surface integrity. Furthermore, the advanced methods that have been developed over the years to enable the improvement of machinability have been reviewed.
... Brass materials are alloys consisting mainly of copper, zinc, lead, iron and nickel [1]. Lead is most often added to brass alloys because of its ability to improve the machinability of the alloys, providing excellent chip breakage and low tool wear [2,3]. However, this element is dangerous to living organisms, including humans, plants, animals and microorganisms, so its use is becoming increasingly restricted [4][5][6][7][8][9][10]. ...
This article presents the results of an experimental study on the effect of the selection of kinematic system for the drilling process on the cylindricity deviation, roundness deviation, diameter error and surface roughness of holes in brass alloy. Three different kinematic systems based on the dependence of the direction of rotation of the workpiece and the drill bit were used. The drill bit was mounted in an axially driven holder that allowed it to be put into motion. Cutting tests were conducted at three different spindle speeds and three different feed rates per revolution (27 tests in total). A static ANOVA analysis was used to evaluate the effect of each input parameter on each output parameter. The results of this work have practical applications in machining. The following input parameters of the drilling process should be used to obtain the smallest values of each output parameter: for CYL, n = 4775 rpm, fn = 0.14 mm/rev and KIN III; for RON, n = 4775 rpm, fn = 0.1 or 0.12 mm/rev and KIN II; for DE, n = 3979 rpm, fn = 0.1 mm/rev and KIN I; and for Rz, n = 4775 rpm, fn = 0.1 mm/rev and KIN II. This research work also used Grey Relational Analysis with which input parameter optimization was derived. The optimal drilling parameters are spindle speeds of 4775 rpm, a feed per revolution of 0.1 mm/rev and the use of the first kinematic system. This paper also includes equations for predicting each parameter that describes the dimensional and shape accuracy and roughness of the hole surface. Using the first kinematic system reduced the roughness of the hole surface by as much as 58%. The correct selection of kinematic system improved its dimensional accuracy by 15%. On the other hand, the roundness deviation of the hole improved by 33% and the cylindricity deviation of the hole by 6%.
... For the investigation within the research, the workpiece CW614N brass alloy sizes φ 40 x 400 mm were selected. (Nobel, 2014) or 360 -500 (Company Sarbak materials data sheets) ...
... Yield strength R p0.2 (MPa) 324 (Nobel, 2014) Hardness HB 154 (Nobel, 2014) or 90 -160 (Company Sarbak materials data sheets) ...
... Yield strength R p0.2 (MPa) 324 (Nobel, 2014) Hardness HB 154 (Nobel, 2014) or 90 -160 (Company Sarbak materials data sheets) ...
Brass alloys are widely used materials for general and industrial applications. However, the lead content in them forces manufacturers to develop new ecological types, the properties of which must be gradually specified in order for the product to be produced and processed more efficiently. The article deals with the evaluation of the machinability of CW614 brass by investigating the influence of technological parameters on the surface roughness of the machined surface and the intensity of vibrations during machining. The measured data were statistically processed; with the help of regression analysis, mathematical formulations of the influence of input parameters on monitored variables were defined and based on them, functional dependencies were plotted in the MATLAB software application. The results showed that at the CW614N brass alloy machining, the feed rate has the greatest influence on the surface roughness Ra, but the depth of cut has the greatest influence on the vibration intensity.
... Due to the advantages of cutting over alternative technologies which often only cover a part of the manufacturing process [1], it is likely to remain a relevant manufacturing technique for components from brass. Small quantities of lead in brass improve the machinability of these alloys by decreasing cutting forces and tool wear and provoking shorter chips [2,3]. On the other hand, the EU and other authorities restrict the use of lead due to environmental and health concerns. ...
... Additionally, the development of a stable chip-tool contact area was inhibited by the above-described mechanism, and therefore cutting forces and friction were lower in the leaded brass alloy [3]. Machining of lead-free or low-lead brass generally results in increased cutting forces and, in some cases, long snarled chips [2,3]. Tools with a positive rake angle might reduce the cutting forces, but this tends to result in longer chips [5,6]. ...
To improve machinability and in particular chip breakability, brass alloys are usually alloyed with small quantities of lead. Due to environmental and health concerns, the use of lead has been restricted in the last years. As lead-free brass alloys are progressively implemented in the industry, challenges arise due to their differing properties from traditional leaded brass alloys. One of the main challenges in automated continuous cutting processes is the worse chip breakability of lead-free brass alloys leading to longer and tangled chips. Hence, the impact of a high-pressure cutting fluid supply, as well as the impact of a chip-breaking geometry and the combined effect of both, has been investigated at different feeds. The three brass alloys CuZn37 (CW508L), CuZn38As (CW511L), and CuZn42 (CW510L) were studied at varying cutting fluid supply pressure levels and feed rates in a radial cutting operation. Cutting forces were measured, and chips were analyzed. No overall systematic impact of the cutting fluid supply pressure on the cutting forces was observed. In conclusion, increased pressure levels, a chip-breaking geometry, and an increased feed rate enhance the chip breakability of the investigated alloys.
... Also, the abrasive and adhesive tool wear is relatively high. These phenomena are explained by the increased ductility and pure face-centered cubic (fcc) α-phase microstructure [2,3]. Leaded brass exhibits a reduced contact length between the tool and chip, along with a lower coefficient of friction, compared to lead-free brass alloys. ...
Lead as an alloying element in brass is legally restricted. Investigations to adapt to the properties of lead-free brass alloys in machining are necessary. The main problems in machining lead-free brass alloys are increased cutting forces and long snarled chips. This paper investigates the impact of the rake angle and different chip-breaking geometries on the chip breakability of the lead-free brass alloy CW511L (CuZn38As). Orthogonal cutting tests were conducted on a lathe. Cutting force measurements, chip analysis, and high-speed camera recordings were performed to analyze the cutting process. The camera recordings were used to analyze the chip formation process with tools with varying chip-breaking geometries. Chips were investigated in microscopic studies. An increased rake angle led to increased chip length but decreased cutting forces. A chip-breaking geometry with a restricted contact length could help to counteract the negative impact of a positive rake angle on the chip breakability with only a marginal effect on the cutting forces. It is crucial to choose a chip-breaking geometry following the cutting parameters. Out of the investigated tools, a tool with a chip breaker land width of 0.7 mm and a groove radius of 3.5 mm was the most beneficial regarding the chip breakability.
... Due to its favorable properties, such as being non-magnetic and having good heat and electrical conductivity, it is widely used in various industries, e.g., sanitary, electrical, and automotive. Small quantities of lead in brass improve the machinability of these alloys by decreasing cutting forces and tool wear and provoking shorter chips [1,2]. On the other hand, the EU and other authorities restrict the use of lead due to environmental and health concerns. ...
... Additionally, the development of a stable chip-tool contact area was inhibited by the above-described mechanism, and therefore cutting forces and friction were lower in the leaded brass alloy [2]. Machining of leadfree or low-lead brass generally results in increased cutting forces and, in some cases, long snarled chips [1,2]. Tools with a positive rake angle might reduce the cutting forces, but this tends to result in longer chips [4,5]. ...
To improve machinability and in particular chip breakability, brass alloys are usually alloyed with small quantities of lead. Due to environmental and health concerns, the use of lead has been restricted in the last years. As lead-free brass alloys are progressively implemented in the industry, challenges arise due to their differing properties from traditional leaded brass alloys. One of the main challenges in automated continuous cutting processes is the worse chip breakability of lead-free brass alloys leading to longer and tangled chips. Hence, the impact of a high-pressure cutting fluid supply, as well as the impact of a chip-breaking geometry and the combined effect of both, has been investigated at different feeds. The three brass alloys CuZn37 (CW508L), CuZn38As (CW511L), and CuZn42 (CW510L) were studied at varying cutting fluid supply pressure levels and feed rates in a radial cutting operation. Cutting forces were measured, and chips were analyzed. No overall systematic impact of the cutting fluid supply pressure on the cutting forces was observed. In conclusion, increased pressure levels, a chip-breaking geometry, and an increased feed rate enhance the chip breakability of the investigated alloys.
... A widely studied lead-free brass is the silicon-alloyed special brass CW724R. CW724R shows increased cutting forces compared to lead-alloyed brass, but lower cutting forces than other lead-free alloys [10]. These are probably caused by the brittle κ-phase, which is precipitated during solidification and as a result of silicon. ...
Components manufactured from brass alloys are widely used in plumbing systems. Traditionally, lead is added to the alloy to improve the machinability. In recent years, the use of lead has been restricted due to health and environmental concerns. New lead-free and low-lead alloys were developed. These alloys usually show a higher cutting force compared to traditional lead-containing brasses. This paper investigates the influence of different rake angles and tool coating on cutting force and chip formation. The two lead-free brass alloys, CW511L and CW724R, are compared to the low-lead brass CW625N.
... Second, lead exhibits a low melting point T m = 327.5 • C. During cutting, lead decreases the chip ductility while a thin, semi-liquid lead film reduces friction and thus cutting forces and tool wear [22][23][24][25]. ...
... The basic characteristics of the brass alloys used in the study are given in Table 1 [29][30][31] and chemical compositions are given in Table 2 [32,33]. [25] 139 [28] 123 [25] 113 [28] 35 [25] 35 [28] * Depending on the method of production. The presence of lead (Pb) in conventional leaded brasses (typical composition rangẽ 2.5-3.5 wt%) favors machinability and machining operations, since it results in chip fracturing, enhances lubrication and reduces cutting force minimizing tool wear, see for instance [23,26,32]. ...
... The basic characteristics of the brass alloys used in the study are given in Table 1 [29][30][31] and chemical compositions are given in Table 2 [32,33]. [25] 139 [28] 123 [25] 113 [28] 35 [25] 35 [28] * Depending on the method of production. The presence of lead (Pb) in conventional leaded brasses (typical composition rangẽ 2.5-3.5 wt%) favors machinability and machining operations, since it results in chip fracturing, enhances lubrication and reduces cutting force minimizing tool wear, see for instance [23,26,32]. ...
The dynamic stability of the machining set and the entire cutting process, together with the appropriate form of chips generated during machining under the given conditions, are the basic prerequisites for autonomous machining in accordance with the Industry 4.0 trend. The research, based on a newly designed method, aims to study the frequency response of the machining system to different values of tool wear and cutting speed, which cause the worsening of the machined parts' quality and the instability of the whole cutting process. The new idea is based on the inverse principle, in which the wear with various values of VB was artificially prepared in advance before machining. Consequently, the effect of artificial wear and cutting speed on vibration and chip shape characteristics were studied. Three types of brass alloys were used within the experiments as the machined materials. Measured data were statistically processed and the desired dependencies were plotted. Chips were collected for each combination of machining conditions, while the article presents a database of the obtained chip shapes at individual cutting speeds so that they can be compared and classified. The results showed that brass alloys CW510L and CW614N exhibit an average of three times lower vibration damping compared to the CW724R alloy, while relatively good chip formation was noted in the evaluated machining conditions even without the use of a chip breaker. The problematic chip shape occurred only in some cases at the machining of CW510L and CW724R, which cannot be generalized.
