Heat Affected Zone Objectives 1. Identify the heat affected zone and the significance of trapped hydrogen. The heat affected zone (HAZ) is a non-melted area of metal that has undergone changes in material properties as a result of being exposed to high temperatures. These changes in material property are usually as a result of welding or high heat cutting. The HAZ is the area between the weld or cut and the base (unaffected), parent metal. 2. Describe the problem of carbon precipitation in a weld. Carbide precipitation occurs when the chrome and carbon in the austenitic stainless steel are drawn out of the material and react to the atmosphere.
