HEAT-TREATED STEEL MATERIAL AND METHOD FOR PRODUCING SAME

This heat-treated steel material has a chemical composition that contains, in mass%, 0.16-0.38% of C, 0.6-1.5% of Mn, 0.4-2.0% of Cr, 0.01-0.10% of Ti, 0.001-0.010% of B, 0.20% or less of Si, 0.05% or less of P, 0.05% or less of S, 0.01% or less of N, 0-2.0% of Ni, 0-1.0% of Cu, 0-1.0% of Mo, 0-1.0% of V, 0-1.0% of Al, 0-1.0% of Nb and 0-0.1% of REM, with the balance made up of Fe and impurities. This heat-treated steel material has a structure that comprises 1.5% by volume or less of residual austenite, with the balance made up of martensite. Este material de acero tratado con calor tiene una composición química que contiene, en % en masa, 0.16-0.38% de C, 0.6-1.5% de Mn, 0.4-2.0% de Cr, 0.01-0.10 % de Ti, 0.001-0.010% de B, 0.20% o menos de Si, 0.05% o menos de P, 0.05% o menos de P, 0.05 o menos de S, 0.01% o menos de N, 0-2.0% de Ni, 0-1.0% de Cu, 0-1.0% de Mo, 0-1.0% de V, 0-1.0% de Al, 0-1.0% de Nb y 0-0.1% de REM, con el balance hecho de Fe e impurezas. Este material de acero tratado con calor tiene una estructura que comprende 1.5% en volumen o menos de austenita residual, el balance hecho de martensita.