| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a high tensile thick steel plate (concretely, a high tensile strength steel plate having excellent toughness in the laser weld metal, and also free from notable hardening in the laser weld metal) for establishing a toughness increasing technique in the laser weld metal of a high tensile strength steel with a thickness of <10 mm. <P>SOLUTION: The high tensile strength thick steel plate has a composition containing, by mass,≤0.06% C, also comprising one or more kinds of elements selected from Si, Mn, Cu, Ni, Mo and V within the valid range(s) of inequality (1), or further comprising one or two kinds selected from Cr and B, and the balance Fe with inevitable impurities, and preferably satisfying inequalities (2) and (3): (1) -ä119.6Mn+18.4Ni+278.3Mo}+ä292.1Si+142.6Cu+2615.1V}≤-80; (2) Ceq=C+Mn/6+Si/24+Ni/40+Cr/5+Mo/4+V/14≥0.34; and (3) P<SB>CM</SB>=C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/15+V/10+5B≥0.17. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
