Optimization of Process Parameters for MIG Welding by Using Grey Relational Analysis

The welding of Aluminium is a big challenge by conventional arc welding process and repeatability of welding depends on its control on welding speed and other processing parameters. In this study, GMAW welding of 5 mm thick mild steel was done by changing the welding current, gas flow rate and nozzle to plate distance to get a high strength joint. To get better strength welding of the MS plate is done from both sides. The main aim of the study was to analyse the Effect of welding current, gas flow rate and nozzle to plate distance on the tensile strength of weld joint, micro hardness of the weld pool and macrostructure of the joint. The mechanical properties under consideration for present work were the Tensile Strength and Hardness. Tensile Strength and Hardness were determined using UTE100, with capacity of 100kN and Rockwell hardness tester respectively. It was found that preheat temperature has the most significant effect on the tensile strength and hardness. The maximum tensile strength and hardness achieved was welding current 124 A, gas flow rate 15 l/min and preheat temperature 275°C.