STEEL MEMBER EXCELLENT IN FATIGUE STRENGTH AND ITS PRODUCTION

摘要

PURPOSE:To improve the fatigue strength of a steel member mixed with relatively large amounts of C and Si by improving its internal hardness. CONSTITUTION:This is a steel member increased in internal hardness by forming retained austenite in a steel member contg., by weight, 0.7 to 1.2% C and 1.5 to 2.5% Si by austempering treatment and subjecting the above retained austenite to nitriding treatment at 450 to 490 deg.C for melting to form its structure into a mixed one of cementite and ferrite and its manufacturing method.