| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a high strength steel sheet for a line pipe in the API X65 grade or higher and to provide a high strength steel sheet for a line pipe having excellent anti-HIC characteristics against HIC generating from a central segregation part, near the surface or an inclusion, at a low cost without adding a large amount of alloy elements. <P>SOLUTION: The high strength steel sheet for a line pipe having excellent anti-HIC characteristics contains, by mass%:≥0.02% and <0.06% C; 0.01 to 0.5% Si; 0.5 to 2% Mn;≤0.01% P;≤0.002% S; 0.05 to 0.5% Mo;≤0.07% Al; and one kind or two or more kinds of 0.005 to 0.04% Ti, 0.005 to 0.07% Nb and 0.005 to 0.1% V; with the ratio of the amount of C to the total amount of Mo, Ti, Nb and V, by atomic%, ranging from 0.5 to 3. The metal structure of the steel is substantially a bainite single phase and contains carbides containing Mo and one kind or two or more kinds of Ti, Nb and V as dispersed and precipitated. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
