| 摘要 |
PURPOSE:To accurately manufacture a high tension hot rolled steel sheet having high magnetic flux density by subjecting a steel slab having a specified compsn. consisting of C, Si, Mn, P, S, Al, N, Ti, B and Fe to specified hot rolling, cooling and coiling. CONSTITUTION:A steel slab consisting of 0.05-0.15% C, <=0.50% Si, 0.70-2.00% Mn, <=0.020% P, <=0.010% S, 0.010-0.10% sol.Al, <=0.0050% N, 0.10-0.30% Ti, 0.0015-0.0050% B and the balance Fe with inevitable impurities is heated to >=1,200 deg.C, hot rolled at a hot rolling finish temp. between the Ar3 transformation point and 950 deg.C, cooled at 30-<70 deg.C/sec cooling rate and coiled at <=500 deg.C. Thus, a high strength hot rolled steel sheet having >=about 80kg/mm<2> yield point, >=about 100kg/mm<2> tensile strength and >=about 1.7 T magnetic flux density B100 is obtd. |
