Stress Relieving / Post weld heat treatment (PWHT)

STRESS RELIEVING (Post weld heat treatment) is the heating of steel to a relatively high temperature (e.g. 500-750 ^oC) shortly after welding, and maintaining that temperature for a specific period of time. The purpose is to reduce internal stresses, caused by welding, quench hardening or by cold working. It also has an advantageous effect on the elasticity, ductility and strength of the metal, carry out by gas fire furnace method or by electric resistance local method