Resistance to Contact Fatigue of Coarse-Grained Gears of Chromium-Nickel Steels

Abstract

The results of complex studies of coarse-grained gears made of carburized chromium-nickel steel 20Kh2N4A are presented. It is shown that with the stable operation of thermal equipment fitted with computer-aided systems for automatic control of the parameters of the technological process of chemical heat treatment in coarse-grained gears of steel 20Kh2N4A, a diffusion layer is formed with a surface hardness of 60–61 HRC and an effective thickness (0.08–0.1)m to a microhardness of 750 HV0.2. It is found that the increased kinematic error after chemical heat treatment of gears made of steel 20Kh2N4A leads to uneven removal of the allowance at the final grinding of the teeth, which is the reason for reducing the resistance of contact fatigue in the local area of the diffusion layers of the teeth.

Keywords

• coarse-grained gear wheels
• chromium-nickel steel
• chemical heat treatment
• kinematic error
• resistance to contact fatigue