Hardenability

[1] The relative importance of the various alloying elements is calculated by finding the equivalent carbon content of the material.

The fluid used for quenching the material influences the cooling rate due to varying thermal conductivities and specific heats.

[3] The hardenability of a ferrous alloy is measured by a Jominy test: a round metal bar of standard size (indicated in the top image) is transformed to 100% austenite through heat treatment, and is then quenched on one end with room-temperature water.

Subsequent to cooling a flat surface is ground on the test piece and the hardenability is then found by measuring the hardness along the bar.

For his pioneering work in heat treating, Jominy was recognized by the American Society for Metals (ASM) with its Albert Sauveur Achievement Award in 1944.

Jominy test dimensioning
Jominy test apparatus
Used Jominy test-piece