The Relevance of the Standard Jominy Test for Rapid/Intensive Quenching

Abstract The relevance of the Jominy End-Quench Test (ASTM A255 or DIN EN ISO 642) is examined in light of novel rapid (intensive) quench methods developed in the last two decades. The Jominy test has been a foundational screening tool for estimating hardenability, comparing materials, and selecting or optimizing low- to medium-carbon alloy steels for design applications. The standard method has many limitations, particularly in its representation of real-world heat transfer conditions during rapid quenching. The modification proposed is to replace the umbrella cooling with a high-pressure spray using an innovative quench box design with an end modified Jominy bar. We show that the hardenability with a standard quench is influenced by the formation of a transient vapor film and underpredicts the "true" hardenability. The film boiling layer appears to be non-uniform, influenced by local surface roughness conditions, and is inconsistently maintained. Eliminating film boiling by direct convective quenching is shown to increase hardenability. Our results show a significant surface and core property difference for abenchmark AISI 1045 steel under standard vs. high-pressure quenching conditions. Today, there is limited adoption of such rapid, high-convection quenching methods commercially. The proposed novel test method adopted as an ASTM standard will allow steelmakers/engineers/designers to optimize their steels for practical rapid quench applications.