Supervisor, Product Research and Development, Lukens Steel Co., Coatesville, Pa.
Pages: 18 Published: Jan 1983
A study of the hardenability of 2¼Cr-1Mo steel shows that the strength of this steel in the quenched and tempered condition can be correlated with the calculated hardenability, as defined by the ideal diameter, D1, but not with an inflection point in the Jominy end-quench hardness-distance curve, J1, for plates in gages from 140 to 214 mm. No correlation is found for plates 76 to 91 mm in gage or when the heavier plates are tempered to a Holloman-Jaffee parameter of 20.7 × 103. These trends are explained by the degree of through hardening and the sequence of precipitations that occur when the quenched steel is tempered.
The 50 percent martensite microstructure in an end quench test has been found to correlate with J1 but not D1. This, and the lack of correlation between J1 and D1 are explained by the methods used to develop each indicator. Both are indicators of 50 percent martensite. J1 indicates the location of the 50 percent martensite microstructure in an end quench bar regardless of the second constituent. D1 calculates the diameter for 50 percent martensite-50 percent pearlite. Since 2¼Cr-1Mo is bainite hardenable, a straightforward correlation is not expected.
hardenability, ideal diameter, Jominy test, mechanical properties, steels, microstructure
Paper ID: STP31768S