STUDY OF THE EFFECT OF BEVEL ANGLE AND WELDING HEAT INPUT ON MECHANICAL PROPERTIES OF MILD STEEL WELDMENTS

Hardness is a very important mechanical property of materials. But during welding high heating and rapid cooling influence the hardness of the weld as well as heat affected zone (HAZ). In the present investigation, 10 rectangular single V-butt manually arc welded mild steel specimens having bevel angle 60˚ and 70˚ (5 specimens each) have been experimented with. The hardness of weld as well as heat affected zone (HAZ) so measured have been correlated with heat input rate using polynomial regression technique. The equations, thus, derived have been used to find out the effect of heat input rate on the hardness of weld as well as heat affected zone (HAZ). By these equations also the optimum hardness of weld and heat affected zone (HAZ) at minimal heat input rate for 60˚ and 70˚ bevel angle weldments have been found out. Also a comparison of optimal hardness for minimal heat input rate of weld and heat affected zone (HAZ) between 60˚ and 70˚ bevel angle weldments have been done.