GALVANNEALED STEEL PLATE, USING HIGH STRENGTH HOT ROLLED STARTING PLATE, EXCELLENT IN FATIGUE CHARACTERISTIC IN WELD ZONE AND ITS PRODUCTION

摘要

PURPOSE: To produce a galvannealed steel plate, using high strength hot rolled starting plate, excellent in fatigue characteristics in a weld zone by preparing a steel plate having a specific composition where respective contents of Nb, Ti, V, P, Cu, Cr, and Mo are specified. ;CONSTITUTION: A plate of a steel having a composition which consists of, by weight, 0.02-0.15% C, ≤0.5% Si, 1.0-2.5% Mn, 0.04-0.15% P, ≤0.010% S, 0.1-0.5% of Cr and/or Mo, 0.01-0.10% Al, ≤1.2% Ni, 0.6-1.6% Cu, 0.05-0.20% Ti, ≤0.08% of Nb and/or V, and the balance Fe with inevitable impurities and where P/(Ti+0.1Mn) is regulated to 0.15-0.5 and P+0.1Cu-0.33(Cr+Mo)≥0% is satisfied is prepared. By this method, the galvannealed steel plate, using high strength hot rolled starting plate, showing superior fatigue characteristics under a severe corrosive environment can be produced.;COPYRIGHT: (C)1993,JPO&Japio