Production of high strength and high ductility resistance welded steel tube

摘要: PURPOSE:To produce a high strength and ductility steel tube for machine structural use used as reinforcing an automotive door or the like. CONSTITUTION:A resistance welded produced by contg. 0.18 to 0.28% C, 0.10 0.50% Si, 0.60 1.80% Mn, =1.0), balance Fe with inevitable impurities is subjected normalizing treatment at 850 95 deg.C thereafter hardening. The hardening may be executed in state which edge parts of are removed away. In this way, having >=1470N/mm tensile well good flatness <=1mm/1m bends can produced.