What does the term "heat-affected zone" (HAZ) refer to in welding?

The term "heat-affected zone" (HAZ) specifically refers to the area adjacent to the weld that experiences changes in its microstructure and properties due to the heat generated during the welding process. This zone is critical because the heat alters the mechanical properties of the metal, such as hardness, strength, and ductility, without actually melting the base material. Understanding the characteristics and implications of the HAZ is essential for welders, as it can affect the overall integrity and performance of the weld joint.

In contrast to the other options, the focus on the adjacent area highlights the significance of temperature gradients and how they impact the surrounding material. While an area that receives too much heat might be related, it doesn’t capture the full impact of structural changes that take place in the HAZ. The mention of porosity being likely at the weld is related to weld quality issues but does not define the HAZ itself. The concept of measuring distance from the electrode to the weld pertains more to the welding technique and setup rather than the thermal effects and zone of influence created during the welding operation.