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|1. (WO2018078844) METHOD FOR PRODUCING STEEL MEMBER, AND STEEL MEMBER|
|Applicants:||NIPPON STEEL & SUMITOMO METAL CORPORATION
|Title:||METHOD FOR PRODUCING STEEL MEMBER, AND STEEL MEMBER|
This method for producing a steel member includes: a step for heating, in a carburizing atmosphere, a steel sheet so as to form a carburizing layer on the surface of the steel sheet, the steel sheet having a chemical composition containing, in terms of mass%, 0.0005-0.1% of C, 0.01-2.0% of Si, 0.05-3.0% of Mn, 0.9% or less of Al, 0.05% or less of P, 0.01% or less of S, 0.0-0.2% of Ti, 0.0-0.1% of Nb, 0-2% of Cr, 0.0-0.2% of Mo and 0.000-0.005% of B, with the remainder being Fe and impurities, and the steel sheet having a steel structure in which the areal proportion of ferrite is 70% or more; and a step for molding the steel sheet in a metal mold and subjecting the steel sheet to quenching while still housed in the metal mold so as to transform the carburizing layer into martensite and obtain a steel structure in which the areal proportion of ferrite is 50% or more in that part of the steel sheet that is further to the inside than the carburizing layer.