Heat Affected Zone in Welded Metallic Materials

Welding is used extensively for pipe welding, aerospace, aviation, biomedical implants, fabrication of race cars, choppers, etc. Generally, the metallurgy of the welded joint performed by thermal fusion joining process can be categorized into two major regions, the fusion zone (FZ) and the heat-affected zone (HAZ). The heat-affected zone (HAZ) is a region that is thermally affected by the welding treatment. The main difficulty associated with welding is the prevention of unexpected deterioration of properties as a result of the microstructure evolutions which reduce the resistance to brittle fracture in the heat-affected zone (HAZ). Properties of the HAZ are different from those of the base material. According to the literature, the HAZ is the most problematic area in the high strength steels weld. For this reason, many research works investigated this critical zone in welded joint. The main research questions and results related to the HAZ will be presented.

Keywords: Welding; Heat affected zone; Microstructure; Mechanical properties; Thermal cycle simulation

Abbreviations: HAZ: Heat Affected Zone; Hv: Hardness Vickers; FZ: Fusion Zone; BM: Base Metal; T-HAZ: True Heat Affected Zone; PMZ: Partially Melted Zone