| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a cold-rolled thin steel strip having higher r value than that of the conventional strip and little variation in the r value andΔr in the whole range of the steel strip and especially having excellent deep-drawability. SOLUTION: A hot-rolling is applied to a steel blank to be formed into a hot-rolled sheet, the steel blank containing≤0.008% C,≤0.2% Si,≤1.0% Mn and further, one or two elements between Ti and Nb so as to simultaneously satisfy (Ti/48+Nb/93)>(C/12+N/14+S/32) and Ti/48>N/14 (wherein, Ti, Nb, C, N, S: content (mass%) of each element). In such a case, as a finish rolling in the hot-rolling, a joined rolling is performed after joining the preceding steel sheet to the following steel sheet to form a hot-rolled steel strip, thereafter repeated bending/bending-back working is applied to the hot-rolled steel strip with a leveller in the temperature range of 500-900°C to give 0.05-2.0 cumulative strain on the surface layer, then this steel strip is wound and annealing and the cold-rolling are applied thereto and further, a recrystallizing-annealing is applied. COPYRIGHT: (C)2005,JPO&NCIPI
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