Abstract
As a low-carbon alloy steel, 20Cr2Ni4A steel has an excellent mechanical properties. It has been used for producing heavy-duty gears, which require good wear and fatigue resistance. The vacuum carburizing process can improve the quality of gears and extend the service life. In this article, a complete heat-treatment process for 20Cr2Ni4A, with carburizing, tempering, quenching and cryogenic steps involved, was proposed. A numerical method was employed to design the carburizing step. The carburized samples were characterized by analysis of carbon profile, surface-retained austenite content, microstructure, and hardness profile. A good microstructure was obtained with acicular-tempered martensite, less-retained austenite, fine granular-dispersed carbides, and was oxide free. The final surface hardness was 64.2HRC, and the case depth was 0.86 mm, which meet the requirements of products. The relationships among process, performance, and microstructure were investigated to understand the inner connection.
| Original language | English |
|---|---|
| Pages (from-to) | 545-550 |
| Number of pages | 6 |
| Journal | Journal of Materials Engineering and Performance |
| Volume | 23 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 2014 |
| Externally published | Yes |
Funding
This work was financially supported by the National Basic Research Program of China (973 Program) (No. 2011CB013404) and National Science and Technology Major Project of the Ministry of Science and Technology of China (No. 2012ZX04012011). The authors are grateful to Mr. Jingchen Lu, Mr. Zijiang Xu and Mr. Peng Zhou from ASIMCO Tianwei Fuel Injection Equipment Stock Co. Ltd. for facility support.
Keywords
- low-carbon alloy steel
- microstructure
- process design
- vacuum carburizing