In welding, like in many other manufacturing and fabrication processes, the process is not complete until the necessary post-processing has been carried out. Post-weld operations are usually performed for reasons such as improving mechanical properties, relieving stress, and improving aesthetics. The two most common Post-weld operations are Post-Weld Heat Treatment (PWHT) and Finishing.
Post-Weld Heat Treatment
During welding, the welded materials are exposed to very high temperatures that can cause micro-structural changes in them. Also, residual stresses build up in welded materials when they are allowed to cool naturally. If left unaddressed, these stresses and structural changes can severely compromise the mechanical properties of a material and can lead to failure during use. To prevent this, PWHT is required for welded parts. There are two major types of Post-weld heat treatment and they are as follows.