What does the heat-affected zone in welding refer to?

The heat-affected zone (HAZ) in welding refers to the portion of the base metal that has undergone changes in physical and metallurgical properties due to the heat generated during the welding process, without actually melting. This area is influenced by the temperature gradients created during welding, which affect the microstructure of the base metal.

In the HAZ, the material may experience hardening, softening, or other modifications depending on factors such as the heat input and the material type. This zone is critical because it can impact the overall strength, ductility, and integrity of the welded joint. Understanding the characteristics and behavior of the heat-affected zone is essential for ensuring the quality and reliability of welds in structural applications.