Formation processability, corrosion resistance, at production mannered null weight proportion of the hot rolling steel sheet which is superior

摘要

PURPOSE: To stably produce a hot rolled steel plate which has softness and superior hole-spreadability and hardly causes aging deterioration at ordinary temp. at the time of working and is remarkably increased in tensile strength and fatigue strength by means of baking finish treatment after working and also has excellent corrosion resistance. ;CONSTITUTION: A steel slab, consisting of ≤0.18% C, 0.30% Si, ≤2.00% Mn, 0.10-0.80% Cu, 0.01-0.50% Ni, 0.020-0.120% P, ≤0.10% sol.Al, 0.0080-0.0250% N, and the balance Fe with inevitable impurities or further containing one or more kinds among 0.0002-0.01% Ca, 0.01-0.10% Zr, 0.002-0.10% rare earth elements, O 01-0 60% Cr, O 01-0 40% Mo, and 0 0003 -0.0050% B, is hot-rolled. After this hot rolling is executed at ≥800°C, the resulting rolled plate is cooled at ≥10°C/s cooling rate and coiled at 350-600°C.;COPYRIGHT: (C)1995,JPO