The steel sheet which is superior in tenacity of the full house thermal welding thermal effect section

摘要

P To provide a steel sheet having excellent toughness in weld-heat affected zone and ≥ 490 MPa tensile strength with a component composition without adding expensive elements, such as Ni and Mo and even in the case of applying a high HEAT input welding exceeding 500 kj/cm. PSOLUTION: The steel sheet has the steel composition composed of and by mass%, 0.01-0.03% C, ≤ 0.5% Si and 0.9 to 2.3% Mn, 1.0-3.9% Cr and ≤ 0.05% Al and 0.005-0.050% Ti and satisfying 35Cr (%) +8Mn (%) ≥ 63 (%) and 7Cr (%) +18Mn (%) ≤ 61 (%), and the balance Fe with inevitable impurities, and wherein, each element in each formula and denotes the content (mass%). PCOPYRIGHT: (C)2010 and JPO& INPIT