| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high-tensile steel sheet capable of completing weldability and stable base metal performance. <P>SOLUTION: The high-tensile steel sheet contains 0.01-0.06 mass% of C and further contains Mn, Cr, Mo, V, Nb, B, Ti, N, Si, Al, P and S. The steel sheet has the following characteristics: KP represented by formula (1): KP=[Mn]+1.5×[Cr]+2×[Mo] satisfies a relation: 2.4≤KP≤4.5; KV represented by formula (2): KV=[V]+[Nb] satisfies a relation: KV≤0.060; at least 90% of area of steel structure is bainite; the average crystal grain size of bainite structure is 5-20 μm; and the average aspect ratio of old austenite particles is 5.0 or more. <P>COPYRIGHT: (C)2012,JPO&INPIT |
