Carburization hardening gear and its production mannered

摘要

PROBLEM TO BE SOLVED: To provide carburized and quenched parts such as a carburized and quenched gear which have high fatigue strength, cause little dimensional change by carburizing and quenching, and cause little deformation by shot peening treatment, and can be applied, particularly, to power transmission parts of an automobile and to provide a production method therefor.;SOLUTION: Alloy steel having a composition containing, by mass, 0.1 to 0.5% C, 0.4 to 1.0% Si, 0.3 to 1.0% Mn, 0.1 to 1.0% Cr, 0.003 to 0.015% P, 0.005 to 0.03% S, 0.01 to 0.06% Al, and 0.005 to 0.03% N, and further containing one or more kinds selected from 0.3 to 1.3% Mo and 0.1 to 1.0% Ni, and the balance Fe with impurities is used as a stock. The stock is formed into a member having a desired shape, and is thereafter subjected to carburizing treatment in an oxidation preventing atmosphere to form a carburized layer. After the carburizing treatment, the member is subjected to quenching treatment where a quenching rapid cooling degree H reaches 0.01 to 0.08 (cm-¹).;COPYRIGHT: (C)2003,JPO