What is the Jominy test?

The Jominy end quench test is used to measure the hardenability of steels. Hardenability differs from hardness in that it is a measure of steel's ability to be hardened to a particular depth rather than a measure of its stability under load.

The Jominy test is performed on a steel sample that is cylindrical and either 100 mm x 25 mm or 102 mm x 25.4 mm in diameter. The sample is austenitized (heated until the steel's crystal structure changes to austenite) at a temperature of 800 to 900 degrees Celsius. The sample is then sprayed with water on one end to simulate quenching.