To corrode the high intensity cold rolling steel sheet and the production manner null which are superior difficult in earth magnetism shielded

摘要

PROBLEM TO BE SOLVED: To produce a cold rolled steel sheet excellent in geomagnetic shielding properties and hard to be corroded as cold-rolled and to provide a method for producing it. ;SOLUTION: This high strength cold rolled steel sheet hard to be corroded and excellent in geomagnetic shielding properties is the one having a compsn. contg., by weight (and so forth as to the steel components), 0.0003 to 0.007% C, 0.5 to 2.5% Si, 0.05 to 2.0% Mn, 0.005 to 0.1% P, 0.0001 to 0.05% S, 0.0001 to 0.1% Al, 0.0005 to 0.005% N, ≤0.05% Ni, and the balance Fe with inevitable impurities, in which the thickness of an Si oxidized film in the surface layer is 1.0 to 7.5 nm.;COPYRIGHT: (C)2000,JPO