| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a high strength hot-rolled steel sheet excellent in the shape and the workability without causing any problem to the recycling, which can stably secure≥80kgf/mm2 strength by compositely adding Nb and Ti as the base without utilizing the addition of Cu and the reinforcement with martensite structure therein. <P>SOLUTION: This high strength hot-rolled steel sheet excellent in the shape and the workability is composed by mass% of 0.08-0.2% C, 1-2.5% Mn,≤1% Si,≤0.05% P,≤0.01% S, 0.01-0.1% sol.Al,≤0.0027% N, 0.05-0.2% Ti, 0.005-0.017% Nb and satisfying following formula (1) and the balance Fe with inevitable impurities. Formula is ä(Nb%/92.9)/(Ti%/47.9)}≤0.100...(1). <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
