Investigation on microhardness and fatigue life in spot welding of quenching and partitioning 1180 steel

• DOI: 10.1016/j.jmrt.2022.06.083
• Publication Date: 2022-06-18T23:41:10Z
• Authors: Jiazhuang Tian; Wu Tao; Shanglu Yang
• Keywords: Tempering; Fatigue limit; Lath; Spot welding

Quenching and partitioning (Q&P) steels are among the most critical third-generation for realizing vehicle weight reduction improving safety performance. It is structure durability to have an excellent fatigue life of welds. In this study, Q&P1180 steel was laser spot welded (LSW) in order evaluate microhardness, mechanical properties, behavior its joints, which were compared with resistance welding (RSW). both types joining methods, zone composed lath martensite high microhardness value. Due tempering, sub-critical heat affected Q&P RSW welds soften, resulting a decrease 52 HV than LSW joint. The presence stress concentration boundary influenced tensile strength all-welded samples failed boundary. Furthermore, limit joint (1.139 kN) about 91.5%t (1.245 kN). Fatigue specimens between fusion heat-affected because their higher sensitivity joint, double eyebrow failure pull-out failure. crack originated from specimen surface propagated through striations together secondary cracks. addition, it found that base metal has inconsequentially when these produced by same method similar geometries.