| 摘要 |
PROBLEM TO BE SOLVED: To provide a high strength steel sheet having API X80 grade or higher showing excellent SR resistant characteristic without adding a large quantity of alloy elements. SOLUTION: In a method for producing the high strength steel sheet, the steel containing, by mass%,≥0.03% to < 0.07% C, 0.01-0.5% Si, 0.5-2% Mn, 0.1-0.5% Mo,≤0.08% Al, one or more of 0.005-0.04% Ti, 0.005-0.07% Nb and 0.005-0.1% V and≥0.14 atomic% total content of Mo, Ti, Nb and V and [C]/([Mo] + [Ti] + [Nb] + [V]) = 0.6-1.7, is heated to 1,100-1,300°C, and after hot-rolling at≥750°C rolling finish temperature, an accelerating cooling to < 400°C at≥20°C/s cooling speed is performed. COPYRIGHT: (C)2005,JPO&NCIPI
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