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A series of spot-welding tests for 22MnB5 steel sheet with a thickness of 1.2 mm was carried out. The welding process and mechanical properties of the plate were analyzed. The results show that the welding pressure and welding current had remarkable effects on the properties of welding joint. Increase of welding current and extension of welding pressure is advantage to eliminate shrinkage porosity defects and could effectively enhance the strength of welding joint. Moreover, the analysis results of the mechanical properties and internal defects also show that the pre-heating pulse is conducive to a spot-welding joint of good performance.

In this paper, the spot welding technology of 22MnMoB hot stamping quenched steel was systematically studied. Through a series of experiments, the optimal spot welding technological parameter has been obtained. The interfacial fracture tendency of spot welds of hot stamping quenched steel behavior was more obvious than that of mild steel. The test results showed that the traditional prediction equation of critical nugget diameter for the changing of fracture mode was not in accordance with test results. A new kind of sphere model which considering the structural complexity of spot weld of hot stamping quenched steel was created to obtain the critical fracture diameter value. The fracture test results of five kinds of hot stamping quenched steel showed that the model has a perfect accuracy which is more accurate and helpful to actual engineering.