Friction Stir Spot Welding of Advanced High-Strength Steels - A Feasibility Study

An exploratory study was conducted to investigate the feasibility of friction stir spot welding advanced highstrength steel sheet metals. The fixed pin approach was used to weld 600MPa dual phase steel and 1310MPa martensitic steel. A single tool, made of polycrystalline cubic boron nitride, survived over one hundred welding trials without noticeable degradation and wear. Solidstate metallurgical bonding was produced with welding time in the range of 2 to 3 seconds, although the bonding ligament width was relatively small. The microstructures and hardness variations in the weld regions are discussed. The results from tensile-shear and cross-tensile tests are also presented. [Application: autobodies].