| 摘要 |
PURPOSE: To cool a steel slab to ordinary temp. without causing cracking by subjecting a low-C and low-N ferritic stainless steel slab, after casting or hot rolling, to heating under specific conditions and then to cooling. CONSTITUTION: A ferritic stainless steel, which has a composition containing, by weight, <=0.03% C, <=0.05% N, and 11-55% Cr as essential components and having the balance Fe with inevitable impurities is used. After this steel is continuously cast or hot-rolled, the resulting slab is heated at a temp. not lower than 400 deg.C and in the range between 900 and 1350 deg.C for a time not shorter than the time (t)(hr) defined by equation, t=(20C+20N+3Cr+5Mo+Ni+5Nb+10 Ti+0.2d)×(1400-T)/7000+0.2 and then cooled. In the equation, C, N, Cr, Mo, Ni, Nb, and Ti are respective percentages by mass, (d) is the thickness (mm) of the steel slab, and T is temp. ( deg.C). If necessary, one or >=2 kinds among <=6% Mo, <=4% Ni, <=0.8% Nb, and <=0.8% Ti are incorporated into the steel composition.
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