Jominyendquench

The Jominy end-quench test is a standardized method for determining the hardenability of steel. Hardenability refers to the depth to which a steel will harden when quenched from its austenitizing temperature. This test was developed by Walter Jominy in the early 1940s.

In the Jominy test, a cylindrical steel specimen is heated to a specific austenitizing temperature and then quenched by a jet of water directed at one end. The water jet creates a precisely controlled cooling rate, with the fastest cooling occurring at the quenched end and progressively slower cooling occurring along the length of the specimen.

After quenching, the specimen is tempered to relieve stresses and then the hardness is measured along the length of the specimen at specified intervals, typically 1/16th of an inch apart. The results are plotted as a curve showing hardness versus distance from the quenched end. This Jominy curve is a characteristic property of a given steel and indicates how its hardness varies with cooling rate.

The Jominy end-quench test is invaluable for metallurgists and engineers in selecting the appropriate steel for a given application. It helps predict how a steel will respond to heat treatment and ensures that the desired hardness and mechanical properties can be achieved at the required depth. The test is widely used in industry to control steel quality and develop new steel alloys.