SPOT-WELDED JOINT OF HIGH-STRENGTH STEEL SHEETS EXCELLENT IN TENSILE STRENGTH, AUTOMOTIVE COMPONENT HAVING THE SAME JOINT, AND SPOT-WELDING METHOD OF HIGH-STRENGTH STEEL SHEETS

摘要

PPROBLEM TO BE SOLVED: To provide a spot-welded joint excellent in tensile strength which can be formed by spot welding of the conventional simple two-stage current pass system combining welding current pass and tempering current pass, and to provide an automotive component having the same spot-welded joint, and a method of spot-welding high-tensile steel sheets. PSOLUTION: The invented spot-welded joint is formed by spot-welding lapped high-strength steel sheets containing 0.10-0.30 mass% C. The Vickers hardness distribution curve from the center of a nugget in the spot-welded joint to a parent metal via a heat-affected zone has a maximal value HvSBmax/SBin the heat-affected zone, and there is a difference (HvSBmax/SB-HvSBmin/SB) of 5 Hv or more between the maximal value and the minimal value of the Vickers hardness (measured under a load of 0.980665N) in the heat-affected zone toward the weld nugget from the point indicating the maximal value. PCOPYRIGHT: (C)2009,JPO&INPIT