Optimization of Process Parameters on the Mechanical Properties of Semi-Solid Extruded AA2017 Alloy Rods

The extrusion of copper-based aluminium alloys is difficult in the cold state. Extruding these alloys between the solidus and liquidus temperatures offer preferred properties on these alloys. In the present work, AA2017, a copper-based aluminium alloy has been extruded in the semi-solid state. The mechanical and metallurgical properties of the alloy vary at different temperatures between the solidus and liquidus temperatures. The aim of the present work is to optimize the process parameters, namely, temperature of billet, strain rate, approach angle and percentage reduction in area on the semi-solid extrusion of AA2017 alloy. Experiments were designed according to Taguchi experimental design and L9 orthogonal array was used to conduct the experiments. Analysis of variance (ANOVA) method was used to find the significance of every process parameter on the thixo-extrusion process responses. The results indicate that percentage reduction area is the most important factor influencing the mechanical properties of thixo-extrusion specimen followed by temperature and strain rate.

Influence of Al Powder on Circularity During Micro-Electro-Discharge Machining of Monel K-500

In the present era, μ-EDM is a promising non-conventional micro-machining process for drilling as well as cutting of electrically conductive materials in the micron range. The objectives of the present research work is to investigate the influence of various parameters such as peak current, pulse ON-time, working time, and aluminium powder concentration on circularity and to find out the significant process parameters based on Taguchi method during micro hole drilling on Monel K-500 with the help of an EDM set-up. Further, a mathematical model has been developed to correlate the relationship between process parameters and circularity based on Response Surface Methodology (RSM). Circularity is increased from 1 to 1.5 A of peak current, from 0.5 to 1.5 sec of working time and from 1 to 4 gm/lit of aluminium concentration. The maximum value of circularity is obtained as 0.976 at the parametric combination of 1.2 A of peak current, 1.8 sec of working time and 3.33 (gm/lit) of Al powder concentration.

Performance Investigation of Powder Mixed Electro Discharge Machining of Hypoeutectic Al-Si Alloy Using Brass Electrode

The aim of this study is the multi- objective optimization of process parameters of Al- Si alloy in powder mixed electrical discharge machining for obtaining minimum surface roughness, minimum tool wear rate, and maximum material removal rate. The important machining parameters were selected as discharge current, voltage and pulse-on time. Experiments were conducted by selecting different operating levels for the three parameters according to Taguchi's Design of Experiments. The multi-objective optimization was performed using Grey Relation Analysis to determine the optimal solution. The Grey Relation Grade values were then analysed using analysis of variance to determine the most contributing input parameter. On analysis it was found that peak current, pulse-on time, and voltage had an influence of 94.73%, 3.32% and 0.36%, respectively, on the multi-performance characteristics.

Influence of Particle Size on Machinability Behavior in Turning of AA6061-AlN Composites

Machinability of the composites and achieving the dimensional accuracy in addition to surface finish at an economic machining rate is still the topic for numerous researchers. The current article describes the variation in machinability characteristics of AA6061-AlN composites under various sizes of reinforcements. Cutting speed, cutting depth and feed rate are preferred to perform the turning test. Cutting force, surface roughness and flank wear are identified to appraise the machinability characteristics. For an identical machining condition, the nano particle reinforced composite has less surface roughness and minimal flank wear and a greater cutting force than the other composites. An increment in cutting speed raises the flank wear and declines the surface roughness and cutting force for all composites. The findings from the experimental investigation help to utilize the turning process for machining the composites with various sizes of reinforcement at the economic rate of machining without compromising the surface quality.

Effect of Temperature and Strain Rate of The Hot Deformation of V Microalloyed Steel on Flow Stress

Medium carbon micro-alloyed forging steels are employed in various automotive components. The impetus for the use of micro alloyed (MA) steels is cost reduction due to elimination of post-forging heat treatment. Compared to conventional quenched and tempered steels micro-alloyed steels can achieve similar or more superior properties simply by properly controlling the process parameters. Forging temperature, strain, strain rate and cooling rate are some of the important process parameters that influence the flow stress and final forging product quality. In the present study, hot compression test on a micro-alloyed steel grade 38MnSiVS5 were conducted on thermo-mechanical simulator (Gleeble-3500) to study the effect of temperature and strain rate on flow stress. The results indicate that the flow stress of 38MnSiVS5 steel is greatly affected by both deformation temperature and strain rate. Obtained true stress-true strain curves showed that the flow stress of the alloy increased by increasing the strain rate and decreasing the temperature, which can be represented in terms of an exponent type Zener-Hollomon equation. Finally, the constitutive equations for the flow behavior of 38MnSiVS5 microalloyed steel were determined.

Optimization of Hot Extrusion Process Parameters Using Taguchi Based Grey Relation Analysis

Enormous applications of aluminium alloys in various key industries necessitated the development and improvement of material processing techniques. Due to simplicity in making complex shapes and low cost of production, the extrusion process for aluminium has gained great popularity in recent years. As the processing variables/parameters during any manufacturing process significantly effects the yield and mechanical properties of extruded products, the development of optimal process parameters combination is found to be vital for the modern manufacturing industries. Hence, the present article addresses the conducting of hot extrusion experiments with AA6061 and evaluation of optimal process parameters using a Taguchi-based GRA. To check the significance of the processing variables on the output quality and quantity, ANOVA is used. A confirmation test was done at the selected optimal processing parameters combination to validate the experimental results.

Springback Prediction Using Finite Element Simulation Incorporated With Hardening Data Acquired From Cyclic Loading Tool

The aims of this article are to present the accuracy of springback prediction in U-bending sheet metal forming processes using finite element (FE) simulation incorporated with kinematics or mixed hardening parameters that are derived from cyclic data provided by the developed cyclic loading tool. The FE simulation results in the form of springback angles are compared with the experimental results for validation. It was found that the mixed hardening model provides better simulation results in predicting springback. This is due to the capability of the isotropic hardening part of this model to describe cyclic transient and the kinematic hardening part to improve description of the Bauschinger effect. Kinematic hardening however, on its own is capable of providing relatively good springback simulation illustrated by errors of less than 8 percent. Overall, the data provided by cyclic loading from the newly developed bending-unbending tool is considered valuable for simulating springback prediction.

Experimental Study on Surface Integrity, Dimensional Accuracy, and Micro-Hardness in Thin-Wall Machining of Aluminum Alloy

This article presents an experimental investigation into the influence of process parameters viz. feed per tooth, axial depth of cut on milling force, surface finish, wall deflection and micro-hardness during thin-wall machining of an aerospace grade aluminum alloy 2024-T351. Results revealed that the process parameters significantly influence the surface finish and dimensional accuracy of machined thin-walls. High feed rate promoted the formation of built-up-edge (BUE). Combination of high feed and axial depth of cut aided in catastrophic failure of tools. Surface damages such as material plucking, material shearing, material adhesion and deformed feed mark layer formation were observed. Axial depth of cut negatively influenced the wall deflection leading to loss of dimensional accuracy. Interestingly, the micro-hardness at the machined surface was found to be lower than that of the bulk material hardness. These results will be useful in selection of suitable process parameters for quality and precise machining of thin-wall parts.

A Study on the Parameters in Hard Turning of High Speed Steel

The objectives of hard turning of high speed steel (HSS-M2 Grade) are to investigate the effect of cutting parameters on cutting force, tool wear and surface integrity. This article presents the experimental results of heat treated high speed steel machined in a CNC lathe using cubic boron nitride (CBN) tools. Turing experiments were carried out using central composite design (CCD) method. From the experiments the influence of cutting parameters and their interactions on cutting forces, temperature and surface roughness (Ra) were analyzed. Following this, multi response optimization was done to find the best combination of parameters for minimum force, minimum temperature and minimum surface roughness. The experimental results showed that the most contributing factors were feed followed by depth of cut and spindle speed. A white layer formed during hard turning was also analyzed by scanning electron microscope (SEM) and the results showed that it was greatly influenced by the speed and depth of cut. Tool wear was experiments were conducted at the optimum cutting conditions and it was noted that the tool satisfactorily performed up to 10 minutes at dry condition.

Investigation on Cutting Force, Flank Wear, and Surface Roughness in Machining of the A356-TiB2/TiC in-situ Composites

This article reveals the experimental investigation on the machinability of A356-TiB2/TiC in-situ composites prepared by a mixed salt reaction system. The fabricated composites are characterized by Energy dispersive analysis (EDAX), X-ray Diffraction (XRD), scanning electron microscopy (SEM) and micro-hardness analysis. Multi-coated tungsten carbide tool was used to examine the influence of TiB2/TiC reinforcement ratio on machinability behaviour of composites. The variations in cutting speed, feed rate and depth of cut upon cutting force, surface roughness and flank wear were examined. The experimental results revealed that the enhancement of a reinforcement ratio causes the decrease in cutting force and increase in flank wear and surface roughness. Higher flank wear is observed, when machining the A356-TiB2/TiC composites at higher cutting speed due to the generation of high temperature at the machining interface. The increment in surface roughness, flank wear and cutting force is experienced at higher depth of cut and feed rate. Further, the mechanisms of chip formation and surface generation under different machining parameters are addressed. The outcome of this experimental investigation helps to utilize the turning process for machining the in-situ composites at economic machining rate without compromising the surface quality.