Bendability, the high intensity cold rolling steel sheet which is superior in deep drawability the high intensity galvanized cold rolling steel sheet and its production method

摘要

PROBLEM TO BE SOLVED: To provide a high strength (galvanized) cold rolled steel sheet excellent in bendability and deep drawability and used for automobiles, house appliances, buildings or the like. ;SOLUTION: This steel sheet has a compsn. contg., by weight, ≤0.0025% C (by ≤0.0050% in the case of being incorporated with Ti and Nb), ≤1.5% Si, 0.7 to 2.5% Mn, ≤0.15% P, ≤0.015% Si, 0.005 to 0.2% Al and ≤0.005% N, suitably contg. 0.005 to 0.15% Ti and 0.005 to 0.15% Nb or 0.010 to 0.15% Ti+Nb and also contg. Si, Mn and P in the relation satisfying 15≤[X=7×Si(%)+6×Mn(%)+110×P(%)]≤30 (by 9 to 25 in the case of being incorporated with Ti and Nb), and the balance Fe with inevitable impurities, in which the X-ray random intensity ratio in the {100} face parallel to the sheet face in the outermost surface of the sheet thickness of the steel sheet is ≥3.0, the X-ray random intensity ratio in the {111} face parallel to the sheet face in the center layer of the sheet thickness in the steel sheet is ≥4.5, and also, sheet thickness is 0.5 to 2.0 mm.;COPYRIGHT: (C)2001,JPO