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The effect of squeeze pressure on hardness of squeeze cast Al-8%Si alloy hardness at squeeze pressure of 0.1MPa refers to those of chill castings.
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This study investigated the effects of squeeze parameters on the properties of squeeze castings and the optimum parameters for producing squeeze castings from Al-Si alloy. It also compared the properties of the squeeze castings with those of chill castings. Squeeze castings were made from Al-8%Si alloy using pressures of 25- 150MPa with the alloy p...
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... relationship between hardness of Al- 8%Si alloy chill castings as well as squeeze castings and squeeze pressure for various pouring temperatures is shown in Fig. 5. The results showed an increase in hardness of Al- 8%Si alloy from HRF39.5-40.5 for chill castings to a maximum of HRF58.0 for squeeze castings which constitutes about 43 to 47% increase over those of chill castings. The increase in the hardness of squeeze cast products is brought about by the faster cooling rates giving rise to grain ...
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Citations
... Pouring is a process by which molten metal is transferred to the cast for cooling and solidification and thus be converted into final product. Pouring temperature is the temperature to which the molten metal has to be raised [5]. Temperature must also take into account the heat loss due to the transfer of metal through ladles. ...
The determination of effects of pouring temperature on mechanical properties of aluminum alloy using statistical method was successfully investigated. The automotive industry faces failures and accidents due to inadequate mechanical properties of cast parts, particularly at higher temperatures. These inadequacies in mechanical properties are not unconnected with their pouring temperature during casting. This study aims to determine the optimal pouring temperature for aluminum alloy casting to achieve optimal mechanical properties. A total of thirty-two (32) casts, were produced via sand mould at four (4) different pouring temperatures namely 660°C, 690°C, 710°C and 740°C which were achieved with the aid of a thermocouple. The specimens were afterwards tested for quality of properties such as density, hardness, water retention capacity and tensile strength, and how these mechanical properties failed under different pouring temperatures. Samples were taken to an Atomic Absorption Spectrometer to test for their chemical composition. Data obtained were analyzed using ANOVA technique. Results showed percentage composition of Al (83%), Si (11%), Cu (3%) and others (3%). It was revealed that variation in the pouring temperature significantly affected the quality of density, tensile strength and hardness, whereas, it had no significant effect on the water retention capacity of the aluminum casts. The optimal pouring temperature is 690°C, with the optimal range being 690°C and 700°C, for producing high-quality casts.
... At pressing pressures of 80 MPa, however, there is a slight decrease in tensile strength. This may be caused, as indicated by the papers [19,24,25], by the formation of stresses at the fiber-matrix interface, damage to the surface of the fibers, and their cracking as a result of too high pressing pressures during solidification of the metal matrix. Figure 5 presents the results of the measurements of the longitudinal modulus of elasticity of the composites and the reference matrix alloy. ...
... Improved hardness of the aluminum alloy is also attributed to the finer grains and minimum porosity obtained as a result of the rapid solidification attained at the higher SP. Number of the grains and grain boundaries increases which enhances the hardness of the alloy [46]. It is also observed that increase in SP increases the density of the alloy and reduces the shrinkage defects which eventually results in better hardness results [47]. ...
Squeeze casting has emerged as an attractive alternative for the casting of aluminum alloys to boost the mechanical and microstructural attributes. However, the alloys practiced in structural applications where ductility is considered a key characteristic, additional heat treatment processes are opted after casting. Considering the industrial applications of Al7050, the current study focused on manufacturing defect-free casting for structural applications. For this purpose, three key process variables including squeeze pressure (SP), melt temperature (MT) and die temperature (DT) have been preferred to improve the percentage elongation, ultimate tensile strength and hardness with minimal casting defects. Annealing treatment is preferred to further advance the ductile behavior of the squeeze-casted Al7050 alloy. Among different process variables, SP has a significant contribution in raising the mechanical properties followed by MT and DT. Taguchi-based Grey relational analysis (GRA) has been used to attain the optimal level of input parameters (SP = 135 MPa, MT, 740 °C and DT = 240 °C) for the superior microstructural and mechanical attributes simultaneously. Microstructural investigations revealed that application of high SP and DT with reasonable MT significantly improved the grain structure and minimized the typical casting defects including micro-voids, porosity and shrinkage cavities. Annealing treatment has been observed productive for improving ductility and reducing the casting defects specifically micro-porosity.
... Raji and Khan [7] investigated the effects of squeeze parameters on the properties of squeeze castings and the optimum parameters for producing squeeze castings from Al-Si alloy. It also compared the properties of the squeeze castings with those of chill castings. ...
... Effect of Pouring Temperature on Formation of Defects Generally, pouring temperature determines the temperature distribution, fluidity and thermal stresses in the casting [11]. High pouring temperature of the melt will result in formation of oxides, rough and dirty casting surface, high shrinkage of liquid metal, and tears and porosity. ...
... This increase in percentage elongation is due to grain refinement and reduction in secondary dendritic arm spacing (Raji and Khan, 2006). 3D plots also reflect that pouring temperature has more effect on percentage elongation than runner area. ...
This research aims to analyze the effects of bottom and top gating configurations on mechanical properties of aluminum alloy 6063-T5 in sand casting process. The influence of three most effective process parameters including pouring temperature, runner area and ingate area have been investigated. Empirical models for both bottom and top gating configurations have been developed using response surface methodology (RSM). Analysis of variance (ANOVA) and confirmatory experiments have been used to measure adequacy and validity of developed models respectively. Bottom gating was observed as better configuration as compared to top gating configuration with 4.08%∼18.78% higher ultimate tensile strength (UTS) and 5.98%∼20.60% higher percentage elongation. This resulted due to splashes generated by top gating configuration which severely affected the fluidity of the melt with consequent effects on mechanical properties. Pouring temperature and ingate area have been identified as the most significant process parameters affecting ultimate tensile strength and percentage elongation. Ingate area, on the other hand influences the flow pressure and speed of melt which is required for mold filling. Micro-hardness of the specimens has also been investigated to clarify the effects of gating configuration and input parameters on mechanical properties. To have a deeper insight of the findings, microstructural analysis of casted parts has also been carried out. The findings of this research will provide better insight of bottom and top gated sand casted parts and their effect on mechanical properties.
... The study showed that the vibration reduces the lamellar spacing and changes the silicon morphology to become more fibrous. Raji A. and Khan R.H. [6] investigated the effects of squeeze parameters on the properties of squeeze cast Al-8%Si alloy. They found that the microstructure of the castings became finer, also density and mechanical properties were increased. ...
... A major drawback of their model is that the analysis was carried out with many assumptions. The pouring temperature and squeeze pressure influences on the mechanical properties were studied [5,6]. It is to be noted that pressure duration and die temperature effects were not considered in their analysis. ...
The present work deals with the forward and reverse modelling of squeeze casting process by utilizing the neural network-based approaches. The important quality characteristics in squeeze casting, namely surface roughness and tensile strength, are significantly influenced by its process variables like pressure duration, squeeze pressure, and pouring and die temperatures. The process variables are considered as input and output to neural network in forward and reverse mapping, respectively. Forward and reverse mappings are carried out utilizing back propagation neural network and genetic algorithm neural network. For both supervised learning networks, batch training is employed using huge training data (input-output data). The input-output data required for training is generated artificially at random by varying process variables between their respective levels. Further, the developed model prediction performances are compared for 15 random test cases. Results have shown that both models are capable to make better predictions, and the models can be used by any novice user without knowing much about the mechanics of materials and the process. However, the genetic algorithm tuned neural network (GA-NN) model prediction performance is found marginally better in forward mapping, whereas BPNN produced better results in reverse mapping.
... The improvement in the mechanical property attributes to the refinement of the microstructure due the externally applied squeeze pressure [5,6]. Investigate the critical process parameters in squeeze casting technique was reported that the squeeze pressure and pouring temperature of 125 MPa and 700 C, respectively, gave an excellent combination of hardness and tensile properties in Al-8% Si alloys having an aspect ratio not more than 2.5: 1 [7]. Aluminium exhibits better machinability than other metals and alloys. ...
The machinability study on newly fabricated A413 alloy produced by squeeze casting route under optimal condition through wire electrical discharge machining process are also investigated as final one of the present work. The experiments were systematically carried out by adapting central composite rotatable design approach of response surface methodology to investigate the effect of wire electrical discharge machining parameters such as pulse on time, pulse off time and peak current on material removal rate and surface roughness. Analysis of variance was also carried out to check the significance of the models. The mathematical models were developed to predict the results which are within the limits of agreeable average error for material removal rate and surface roughness through additivity test. Desirability function approach was used to find the optimal parametric combinations for multi-objective optimization and successful machining of the castings/composite. It has been verified by confirmatory experiment to show the efficiency of the proposed method. On the whole, it is stated that the investigation on squeeze casting and wire electrical discharge machining process parameter of A413 alloy have proved the better casting properties and machining quality. Hence, it is recommended for all industrial applications especially automobile, aerospace.
... The refined microstructure with smaller dendrite cell size and closer spacing of silicon particles was observed at higher values of squeeze pressure. Moreover, the influence of casting temperature and squeeze pressure on the mechanical properties of the component was studied using classical engineering experimental (varying one parameter at once while keeping other parameters constant) approaches [5,[11][12]. In addition to the said approaches, the influence of casting temperature on mechanical properties was studied in [13] for the fixed die temperature, squeeze pressure and pressure durations. ...
... The parameters are iteratively updated for its positions and velocity using Eq. [12] and [13], respectively. ...
The near net shaped manufacturing ability of squeeze casting process requiresto set the process variable combinations at their optimal levels to obtain both aesthetic appearance and internal soundness of the cast parts. The aesthetic and internal soundness of cast parts deal with surface roughness and tensile strength those can readily put the part in service without the requirement of costly secondary manufacturing processes (like polishing, shot blasting, plating, hear treatment etc.). It is difficult to determine the levels of the process variable (that is, pressure duration, squeeze pressure, pouring temperature and die temperature) combinations for extreme values of the responses (that is, surface roughness, yield strength and ultimate tensile strength) due to conflicting requirements. In the present manuscript, three population based search and optimization methods, namely genetic algorithm (GA), particle swarm optimization (PSO) and multi-objective particle swarm optimization based on crowding distance (MOPSO-CD) methods have been used to optimize multiple outputs simultaneously. Further, validation test has been conducted for the optimal casting conditions suggested by GA, PSO and MOPSO-CD. The results showed that PSO outperformed GA with regard to computation time.
