The Jominy end-quench test is used to measure the hardenability of a steel, which is a measure of the capacity of the steel to harden in depth under a given set of conditions. This article considers the basic concepts of hardenability and the Jominy test.

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Hardenability is the ability of steel to partially or completely transform from austenite to some fraction of martensite at a given depth below the surface when cooled under a certain condition. The “gold standard” test for all hardenability results has always been the “Jominy End-Quench Test.” 

The Jominy, or end-quench test, determines the capacity of steel to harden under defined heating and cooling parameters. ASTM A255 (Standard Test Methods for Determining Hardenability of Steels) provides the guidelines/procedures for performing the Jominy test.