Hardenability: The ability of a steel to form subsurface martensite
Jominy End-Quench Test: used to measure martensite
Quench avoids transformation into stable phases (ferrite, cementite)
Jominy End-Quench Test
The Jominy End-Quench test basically consists of heating a steel 1″ diameter cylindrical sample to high temperature (the steel must be austenized), then placing in a holder and having cold water sprayed on one end. As the steel cools, it will form martensite close to the quenched end. Once the sample is fully cooled, a flat channel is ground into the side and hardness measurements taken according to ASTM standards. Care must be taken in grinding the channel as to not locally heat treat the steel.