NDT - Phils., Inspection Services Corporation

Post Weld Heat Treatment (PWHT) reduces the residual stresses formed during welding. It also restores the macro structure of the steel. Mandatory in high pressure applications, constructors have to strictly follow PWHT requirements to avoid component failures

PWHT eliminates the effects by heating, soaking, and cooling the weld area in a controlled manner to temperatures below the first transformation point, giving the macro structure sufficient time to readjust to its original state and removing the residual stress.