| 摘要 |
PROBLEM TO BE SOLVED: To uniformize the quality of a hot-rolled steel sheet over the whole length, to avoid the defective quality at the front end part, to improve the cost merit by saving energy in a heating furnace and to produce the hot-rolled steel sheet for working excellent in the deep drawability. SOLUTION: A steel slab having <=0.1% carbon content is heated to <=1150 deg.C extraction temp. in the heating furnace and the roughly rolled steel sheet is coiled at >=0.5% bending strain and >=0.05s<-1> bending strain speed and held at <=1 deg.C/s cooling speed for >=3sec. Thereafter, uncoiling is executed and successively, the front end part of this steel sheet is joined with the rear end part of the steel sheet roughly rolled theretofore and preceding the rolling line, and the hot finish-rolling is continuously executed in the temp. range of theαzone at <=750 deg.C and after completing the rolling, the recoiling is executed at 600-750 deg.C.
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