CASE HARDENING STEEL EXCELLENT IN BEARING FATIGUE-STRENGTH, IMPACT-STRENGTH AND BENDING FATIGUE-STRENGTH

摘要

PROBLEM TO BE SOLVED: To provide a high strength case hardening steel improving the main characteristics of a gear at a low cost by obtaining both of the improvement of a bearing strength and an impact-strength and the improvement of a rotation-bending fatigue-strength in a carburized gear.;SOLUTION: The case hardening steel for a gear, excellent in the bearing strength, the impact-strength and the bending fatigue-strength, is manufactured as the followings, that to the steel composed by mass% of 0.10-0.35% C, 0.40-1.50% Si, 0.10-1.50% Mn, ≤0.030% P, ≤0.030% S, 0.50-3.0% Cr, 0.02-0.20% Ti, 0.02-0.05% Al, 0.0010-0.0050% B, ≤0.01% N and satisfied to Ti3.4N and 7Si+3Cr+Mn≥7.0 and the balance Fe with inevitable impurities, a gas-carburizing and a quenching-tempering in the processes shown in Figure 4, are applied.;COPYRIGHT: (C)2009,JPO&INPIT