| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a high-strength steel tube with which the high strength steel tube having≥590 MPa TS, suitable to a round tube, a square tube and a deformed tube, etc., used for constructive members for automobile. SOLUTION: The steel tube composed by mass% of 0.005-0.50% C,≤0.6% Si, 0.3-3.0% Mn,≤0.02% P,≤0.006% S, 0.001-0.08% Al, 0.001-0.006% N,≤0.006% O and further, at least one or more among 0.5-1.2% Cu, 0.005-0.10% Nb and 0.01-0.10% V and the balance Fe with inevitable impurities, is made to be a raw tube stock, and after performing tube extending work at cold-rolling to this raw tube stock so as to become 10-60% reduction area ratio, a heat-treatment in the temperature range of 500-650°C for 30 sec, is applied and successively, air-cooling is performed as the manufacturing method. COPYRIGHT: (C)2008,JPO&INPIT
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