Effect of Preheating the Work Piece Material on the Width of Heat Affected Zone of Cast Iron and Mild Steel Weldments

A systematic study on the effects of preheating temperatures of the work piece material on the width of Heat Affected Zone (HAZ) formed during arc welding of Gray Cast iron with Mild Steel reveals that under identical conditions, the width of 'HAZ' on both cast iron and mild steel get reduced initially with preheating temperatures followed by a rise with further increase of the same. It also reveales that under identical conditions, the width of 'HAZ' on cast iron is always less than that on mild steel. All these observations have been explained with the help of proposed temperature distribution model diagrams for the work piece materials based on the effects of preheating temperatures and thermal conductivitys of the same.