The effect of microstructure on hardness and toughness of low carbon welded steel using inert gas welding

► In this research we increase the welding parameters such as amperage and voltage, as a result of which HAZ and WM area are extended. ► Rising voltage causes to increase grain area in HAZ. ► As a result of increasing grain size, hardness and toughness decline significantly. ► On the other hand, when voltage is raised, the amount of perlite and ferrite decreases and increases respectively. ► Generally, it can be seen that when voltage and amperage are increased in welding process, the mechanical properties of welded specimen decline.