Heat-Affected Zone
Glossary · Shop Floor
At a glance
- Category /
- Shop Floor
- Also called /
- HAZ
- Related /
- 3 terms
- Source /
- Written in the shop
The heat-affected zone is the band of parent material next to a weld whose properties have been changed by the heat of welding without being melted.
Also called: HAZ
In practice
It has not been melted, but it has effectively been heat treated by proximity — so its hardness, grain structure and toughness differ from both the weld and the untouched base metal.
Why it matters
The HAZ is frequently where a welded joint fails, not the weld itself. On hardened or high-strength material it can end up harder and more brittle than anything around it.
More in Shop Floor
Have a drawing with this on it?
Request a Quote
Send it over and we will tell you what it will take to hold — and what is safe to loosen.