Analysis of heat affected zone of MIG welded mild steel specimen

The present work investigates the effect of welding condition according to mechanical properties of mild steel and presents the optimum welding condition through the evaluation about the weld ability of mild steel by the welding conditions such as the welding passes, voltage variation, current, variation, and change in thickness of mild steel flats. In order to find out optimum welding condition by the mechanical properties, mild steel (0.134% carbon) was selected as a specimen having thickness 5, 8,16mm and were prepared for experiment.Specimens were welded in the range of 20-24 Volt, 130-150 Amp and test pieces out of these for test of tension, impact and hardness and micro structure have been extracted. The experimental result revealed that with increase in voltage there is increase in penetration so using the parameters further welding was performed. Results show that with increase in current there is increase in hardness of HAZ and ultimate tensile strength .Also increase in number of passes causes decrease in hardness and ultimate tensile strength. The impact absorption energy shows an increase in energy with increase in no of passes.