Very good addition of Cu thin steel sheet of the surface properties

摘要

PURPOSE: To economically obtain the Cu-added thin steel sheet having extremely outstanding surface characteristic without generating surface flaws by adding a specific ratio of Ni only to the surface layer part of the extra low-to low-C steel having a specific compsn. contg. a specific ratio of Cu. ;CONSTITUTION: The Ni; Ni/Cu are incorporated at 0.6 to 1.0 only into the surface layer part of the Cu-added thin steel sheet contg. 0.0010 to 0.100mass% C, 0.1 to 2.0% Mn, 0.8 to 2.0% Cu, 0.005 to 0.07%sol Al, and further ≤1.5% Si and/or ≤0.1% P, and further at need contg. 0.01 to 0.1 Ti and/or 0.01 to 0.1% Nb or 0.0001 to 0.0030% B and consisting of the balance Fe and unavoidable impurities. The cladding rate is preferably controlled to about 6 to 20 inside layer/outside layer ratio at this time. The above-mentioned thin steel sheet is obtd. by producing a steel slab consisting of the inside and outside layers of the prescribed component compsn. by a casting and cladding method and subjecting the slab to hot rolling and further to cold rolling at need.;COPYRIGHT: (C)1993,JPO&Japio