HIGH TENSILE STRENGTH STEEL SHEET FOR DEEP DRAWING EXCELLENT IN SURFACE TREATING PROPERTY AND ITS PRODUCTION

摘要

PURPOSE:To obtain a steel sheet for deep drawing excellent in the balance. between strength and deep drawability as well as in various surface treating properties by incorporating specific amounts of C, Si, Mn, Mo, B, Al, P, S, N, Ti, and Nb. CONSTITUTION:This steel sheet has a composition which consists of, by weight, 0.001-0.05% C, =1% Si, =2.5% Mn, 0.05-1% Mo, 0.0005-0.01% B, 0.01-0.1% Al, =0.15% P, =0.01% S, =0.006% N, further either or both of =0.3% Ti and 0.001-0.2% Nb under the relations in equation I and inequality II, and the balance essentially iron and in which respective contents of Si, Mn, and P satisfy the relations in inequality III, where Ti*=0 in the case of Ti-(48/32)S-(48/14)N0. Besides the addition of Mo, B, and Ti and/or Nb, the elements of Si, Mn, and P having high property of strengthening entering into solid solution are well-balancedly incorporated, in consideration of their respective actions.