How large is the heat-affected zone of a weld?

The heat-affected zone of a weld refers to the area adjacent to the weld that is affected by heat during the welding process. Its size depends on various factors, such as the workpiece material and welding process parameters. Generally, the heat-affected zone of a weld is smaller than the welding area. In common welding processes, the welding temperature is usually higher than the melting point of the workpiece and remains at that level for a certain period of time; this results in significant thermal effects in the areas near the weld, causing changes in the material’s microstructure, as well as differences in the properties of those areas affected by heat. For materials such as high-strength, low-alloy steels, whose microstructure is relatively fine, the heat-affected zone is relatively small; whereas for materials such as cast irons, which have a higher carbon content, the heat-affected zone can be relatively large. In summary, the size of the heat-affected zone in a weld is a complex issue that requires consideration of various factors, rather than a simple fixed value. .