Weld Heat Affected Zone (HAZ) Estimator
A tool to provide a qualitative estimate of the size of the Heat Affected Zone (HAZ) in steel, based on heat input and material thickness.
Welding Parameters
Enter the heat input and plate thickness to estimate the HAZ width.
The Unseen Transformation: Understanding the HAZ
The Heat Affected Zone (HAZ) is the area of base metal that has not been melted, but whose microstructure and mechanical properties have been altered by the heat of welding. This zone can be the weakest part of a weldment if not controlled properly. For example, in some high-strength steels, the HAZ can become very hard and brittle, making it prone to cracking. Controlling the size of the HAZ is a key aspect of welding engineering.
Factors Influencing HAZ Size
- Heat Input: This is the most dominant factor. Higher heat input puts more energy into the plate, resulting in a larger HAZ.
- Material Thickness: Thicker materials act as a larger "heat sink," drawing heat away from the weld more quickly. This results in a smaller HAZ compared to a thin plate welded with the same parameters.
- Preheat Temperature: A higher preheat temperature slows the cooling rate and will generally result in a wider HAZ.