The Relevance of the Standard Jominy End Quench Test for Rapid Quenching

The relevance of the Jominy End-Quench Test (ASTM A255/ DIN EN ISO 642) is examined in this study. This standardized test is a foundational tool for ranking hardenability, comparing materials, and selecting or optimizing low to medium-carbon alloy steels. We demonstrate that the ASTM standard test method exhibits critical deficiencies, particularly in its representation of real-world heat transfer conditions during quenching. Specifically, the rate of heat transfer is significantly influenced by the formation of a transient vapor film (Leidenfrost layer), which acts as an insulating thermal barrier. This layer is highly non-uniform, influenced by local surface conditions, and inconsistently maintained under the standard quench pressure (40 psi). These issues can be mitigated using high-velocity, high-volume water flow that strips away the vapor layer, enabling ideal convective heat transfer. Despite this, the adoption of intensive, high-convection quenching in commercial heat treatment remains limited, largely due to the absence of a standardized test methodology. We propose a modification to the ASTM A255 test through the use of a novel test chamber that enables rapid quenching by removing the vapor barrier. Our results show a significant difference in hardenability for a benchmark AISI 1045 steel under standard versus high-pressure (>150 psi) quenching conditions.