What characteristic is typically enhanced by post-weld heat treatment?

Post-weld heat treatment (PWHT) is employed to relieve residual stresses, improve ductility, and reduce hardness in welded materials. During the welding process, the heat can create hard and brittle microstructures, leading to increased susceptibility to cracking and reduced ductility. By applying heat in a controlled manner after the welding has occurred, the material undergoes transformations in its microstructure, which helps to restore or improve ductility.

This treatment allows for the redistribution of residual stresses that occur due to the heating and cooling cycles of welding. It enhances the overall mechanical properties of the welded joint, making it less prone to failure under various loads. While other properties such as hardness, corrosion resistance, and electrical conductivity may be influenced by PWHT, the primary focus and benefit lie in improving ductility, allowing for better performance of the welded assembly in service.

The other attributes like hardness can actually be reduced through PWHT, and corrosion resistance is more influenced by the chemical composition of the base metal and the weld rather than a direct effect of heat treatment. Electrical conductivity isn’t a primary concern that PWHT addresses in the context of welding.