After the forming, carburization treating dedendum flexural strength and the high intensity gear and its production

摘要

PROBLEM TO BE SOLVED: To provide a gear which can be produced at a low cost, and has excellent pitting resistance, and to provide a production method therefor.;SOLUTION: Steel having a composition containing, by weight, 0.10 to 0.30% C, 0.50 to 1.50% Si, 0.30 to 1.00% Mn, ≤0.035% P, ≤0.035% S, 0.20 to 0.50% Cr, 0.35 to 0.80% Mo, 0.020 to 0.060% Al and 0.0080 to 0.0200% N, and also satisfying 1.5≤3 Si(%)-Mn(%)+Cr(%)/4+Mo(%), and the balance Fe with impurities is subjected to carburization treatment. The gear has a carburization layer having a C concentration of ≥0.60%, and a retained austenite content of ≤20%, and the outer layer thereof is provided with a carburization abnormal layer having the maximum depth of 5 to 13 μm. The area ratio occupied by the carburization abnormal layer in the cross section from the position of the maximum depth to the surface is ≥70%.;COPYRIGHT: (C)2003,JPO