Correlation Between Jominy Test and Quenched Round Bars 410117
A NUMBER of different tests have been developed for ascertaining the hardenability of steel, that is, its susceptibility to hardening by quenching. Although each of these different tests may be suited particularly to a specific problem, it would be useful to know how to interpret one test in terms of another. The present paper suggests a manner of correlating the extent of hardening in the Jominy-Boegehold end-quench test with the extent of hardening in quenched round bars.
For any particular steel, the extent to which it hardens when quenched varies with the cooling rate (cooling time) in the quench. That is, if cooled rapidly enough, it will become hard and, if cooled slowly, it will be soft, so that for each steel a series of hardnesses may be found experimentally corresponding to a series of cooling times. Different cooling times occur along the length of a Jominy bar, and various cooling times are also found at various positions in different sizes of quenched bars, quenched with various severities of quench.
It therefore becomes possible to predict from the results of a Jominy test what the hardness distribution will be on the cross-section of a quenched round bar when quenched with a known severity of quench.