| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for manufacturing a hot rolling steel plate superior in acid pickling performance and surface property and used as an automobile member, a building material or a cold rolling raw material and the like. SOLUTION: During a rough rolling process, a billet containing 0.005-0.1 wt.% Ni is descaled once or more with a high pressure water jet of 160 kgf/cm2 or over and is rolled in such a manner that the temperature after the descaling does not exceed 1,170 deg.C. After completion of the rough rolling and before applying a finish rolling, a heat insulation is conducted with an induction heating, under an atmosphere where an oxygen density is 3% or more so that an insulation temperature: T( deg.C), a heat insulation time: t (sec) and Ni containing volume: Ni% satisfy the formula: 30>=t>=(3.4×105)/ (Ni%+0.016)T2}. Thereafter, the descaling is carried out under a condition where a pressure of the high pressure water jet: P (kgf/cm2) satisfies the formula, 160>=P>=2.2×105×(Ni%+0.5)/(log60t+T), wherein T is 950-1,170 deg.C.</p> |
