Sachin Ambade

In this study, three different arc welding processes, namely tungsten inert gas (TIG), metal inert gas (MIG) and shielded metal arc welding (SMAW) processes, are used to weld 409 M ferritic stainless steel. K-type thermocouples are located in the area of heat-affected zone by drilling blind holes in a plate at a distance of 3 mm and 7 mm from the weld line, revealing the contours of the temperature distribution of the weld. The experimental results are compared with the results of simulations using ANSYS by Goldak heat source model. The temperature is experimentally measured in the heat-affected region with the help of a thermocouple. The temperature distribution profile by the finite element method using ANSYS is compared with the experimental temperature distribution profile with the heat source. The experimental and simulation results for TIG, MIG and SMAW welding processes have been found to be excellent.

This experimental study investigates the effects of welding low nickel Cr-Mn austenitic stainless steel with gas tungsten arc welding process with and without filler (autogenous) weld by varying the welding currents (120A, 130A and 140A). The microstructural examination of weld has been carried out with optical microscope and mechanical properties with Vickers microhardness and tensile tester. The corrosion behaviour of the welded joints are analysed by double loop electrochemical potentio-kinetic reactivation test to obtain degree of sensitisation. The microstructural examination of welded joints revealed that, as the welding current increases, the inter-dendritic spacing as well as the dendrite size increases. The tensile strength and hardness decrease with increasing welding current for 308 L filler and autogenous weld. The degree of sensitisation increases with increasing welding current for both the welds. The results reveal that the autogenous welds have higher tensile strength, higher hardness and lower degree of sensitisation as compared to welds with 308 L filler.

This paper presents a novel Variable Oscillating EDM process through a mechanism provided on the Z-axis numerical control EDM for machining the curvature channel. The specific trajectory is machined inside the oil hardening non-shrinking steel workpiece through the curved copper electrode. In order to execute the experiments, critical input machining parameters (sparking current, pulse on time, pulse off time, and swing sensitivity) and output process characteristics (Electrode wear rate and material removal rate) are selected. Taguchi experimental design (L9) is used to design the experiments. The pulse off time has a significant effect on VOEDM process characteristics. Analysis of variance is used to identify the significant contributions of selected parameters. It identifies the major contributing factor to be the pulse off time for EWR (50.33%) and MRR (34.78%). The machining parameters optimised using regression analysis adopting a forward selection method. Finally, confirmation runs are performed to evaluate the results of optimal combination of machining parameters with output characteristics. The average experimental values at optimum conditions for achieving minimum EWR and maximum MRR are 0.000194mm³/min and 0.000397mm³/min, respectively. Further, SEM was used for analysing the material behaviour of workpiece. The experimental results confirm the validity and sustainability of the VOEDM process.