This SAE Information Report summarizes the characteristics of carburized steels and factors involved in controlling hardness, microstructure, and residual stress. Methods of determining case hardenability are reviewed, as well as methods to test for freedom from non-martensitic structures in the carburized case. Factors influencing case hardenability are also reviewed. Methods of predicting case hardenability are included, with examples of calculations for several standard carburizing steels. A bibliography is included in 2.2. The references provide more detailed information on the topics discussed in this document.