This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Method of Hardening Case-Carburized Steels
Annotation ability available
Sector:
Language:
English
Abstract
A 4-step heat treatment for hardening case-carburized steels has been developed and is here described and compared with conventional hardening. In step 1 of this new method, steel is case carburized and oil quenched; much higher than normal carburizing temperatures can be used. Step 2 eliminates retained austenite by heating in the bainite region, for example, 700 F for 2 h. Step 3 is a rapid austenitizing treatment followed by an oil quench, and step 4 a temper at ∼400 F.
Three representative grades of low-alloy steels were investigated to determine their response to this new hardening treatment and to explore the variables which influence the product. It is shown that the treatment permits faster carburizing without affecting the quality of the case by carburizing at least as high as 1900 F.
The new 4-step hardening method is shown to have the following principal advantages over conventional methods:
-
1.
It develops higher hardness in the outer case.
-
2.
It refines the grain size of both case and core.
-
3.
It makes it feasible to use higher carburizing temperatures and hence shorten the carburizing cycle.
-
4.
It develops a case microstructure relatively less affected by chemical composition of the steel or by carburizing variables. It offers promise of improving the performance of case-carburized parts (gears, bearing races, etc.).
Authors
Citation
Grange, R., "Method of Hardening Case-Carburized Steels," SAE Technical Paper 730143, 1973, https://doi.org/10.4271/730143.Also In
References
- Jominy Walter E. “High Temperature Carburizing-The Process Works.” Metal Progress 85 May 1964 70
- Bullens D. K. et al. “Steel and Its Heat Treatment, Vol. II-Tools, Processes, Control.” New York John Wiley & Sons, Inc. 1948
- “Atlas of I-T Diagrams.” United States Steel Corp. Pittsburgh 1963
- Grange R. A. “Method of Hardening Hypereutectoid Steels.” Aug. 22 1967
- Metals Handbook American Society for Metals Metals Park, Ohio 1948 98
- McQuaid H. W. “A Study of the Effect of Aluminum Addition to the Structure of a Quenched Carbon Steel.” ASM Transactions 25 1937 490 519