Deep drawing Characteristic and the resistance secondary processed ze are and are superior in Characteristic the high intensity cold rolling steel sheet and its production manner

摘要

PURPOSE: To obtain a steel plate combining not only workability but also plating properties as well as secondary working brittleness resistance or the like as a high strength steel plate used for an automobile or the like. ;CONSTITUTION: The steel plate has composition contg., by weight, 0.0005 to 0.0050% C, 0.10 to 1.50% Si, 1.00 to 3.50% Mn, 0.020 to 1.000% Ni, 0.015 to 0.100% Ti, 0.003 to 0.040% Nb, 0.0005 to 0.0050% B, ≤0.030% Al, 0.040 to 0.150% P, ≤0.010% S and ≤0.0050% N. Furthermore, it contains Si, Mn, Ni and P under the conditions in which %Si, %Mn, %Ni and %P, i.e., their each content, satisfy -50≤A0 by A value calculated by the following expression of A=100×%P+80×%Si-60×{%Mn+%Ni}, and the balance Fe with inevitable impurities. Moreover, its structure is formed of polygonal ferrite and a low temp. transformation phase of ≥3% volume rate.;COPYRIGHT: (C)1994,JPO&Japio