Distortion control in 20MnCr5 bevel gears after liquid nitriding process to maintain precision dimensions

International Conference on Advances in Metallurgy, Materials and Manufacturing

冶金学;材料科学;机械制造

Mahendiran, M.^1 ; Kavitha, M.^2

Eppinger Tooling Asia, Tamilnadu Coimbatore

642 109, India^1

Department of Metallurgical Engineering, PSG College of Technology, Tamilnadu Coimbatore

641 004, India^2

关键词: Dimensional control;    Distortion control;    Grinding process;    High precision components;    Liquid nitriding;    Process parameters;    Surface hardness;    Wear-resistant coating;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/314/1/012001/pdf
DOI  :  10.1088/1757-899X/314/1/012001

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Robotic and automotive gears are generally very high precision components with limitations in tolerances. Bevel gears are more widely used and dimensionally very close tolerance components that need stability without any backlash or distortion for smooth and trouble free functions. Nitriding is carried out to enhance wear resistance of the surface. The aim of this paper is to reduce the distortion in liquid nitriding process, though plasma nitriding is preferred for high precision components. Various trials were conducted to optimize the process parameters, considering pre dimensional setting for nominal nitriding layer growth. Surface cleaning, suitable fixtures and stress relieving operations were also done to optimize the process. Micro structural analysis and Vickers hardness testing were carried out for analyzing the phase changes, variation in surface hardness and case depth. CNC gear testing machine was used for determining the distortion level. The presence of white layer was found for about 10-15μm in the case depth of 250± 3.5μm showing an average surface hardness of 670 HV. Hence the economical liquid nitriding process was successfully used for producing high hardness and wear resistant coating over 20MnCr5 material with less distortion and reduced secondary grinding process for dimensional control.