| 摘要 |
<p>PURPOSE: To prevent the occurrence of cracks in a cast slab at the time of continuously casting a steel containing tramp elements in a steel composition, to improve the hot workability of the slab, and to produce a hot rolled steel plate free from surface flaw and excellent in quality. CONSTITUTION: This hot rolled steel plate has a composition consisting of 0.01-0.15% C, <=0.3% Si, 0.1-1.0% Mn, <=0.03% P, <=0.025% S, 0.01-0.07% sol.Al, <=0.012% N, 0.04-0.4% Cu, 0.004-0.04% Sn, 0.01-0.1% Ni, 0.01-0.1% Cr, 0.01-0.1% Mo, and Fe, satisfying C+(Cu+5Sn)/3<=0.25% in the stage of a molten steel, and also satisfying Cu+10Sn<=0.4% in the stage of a slab. A steel having this composition is refined and cast into a slab by continuous casting. The cast slab is heated to >=1100 deg.C, and both edges of the heated slab, in a plate-width direction, are heated by means of edge heaters. Then, the slab is hot-rolled at a finishing temp. not lower than the Ar3 transformation point and coiled at 500-700 deg.C. By this method, the hot rolled steel plate free from crack and surface flaw can be produced.</p> |
