ABRASION-RESISTANT STEEL SHEET EXHIBITING EXCELLENT RESISTANCE TO STRESS CORROSION CRACKING, AND METHOD FOR PRODUCING SAME

摘要

Provided is an abrasion resistant steel plate or steel sheet suitable for use in construction machines, industrial machines, and the like and a method for manufacturing the same. In particular, a steel plate or steel sheet excellent in resistance to stress corrosion cracking has a composition containing 0.20% to 0.30% C, 0.05% to 1.0% Si, 0.40% to 1.20% Mn, P, S, 0.1% or less Al, 0.01% or less N, and 0.0003% to 0.0030% B on a mass basis, the composition further containing one or more of Cr, Mo, and W, the composition further containing one or more of Nb, Ti, Cu, Ni, V, an REM, Ca, and Mg as required, the remainder being Fe and inevitable impurities. DI* due to contained components is 45 or more. A microstructure has a base phase or main phase that is tempered martensite. Cementite having a grain size of 0.05 µm or less in terms of equivalent circle diameter is present in the steel plate or steel sheet at 2 x 10 6 grains/mm 2 or more. A semi-finished product having the above steel composition is heated, hot rolling is performed, air cooling is performed, reheating is performed, and accelerated cooling is then performed or accelerated cooling is performed immediately after hot rolling.