A hardenability test in which a standard test piece, 4 in (10.2 cm) long and 1 in (2.54 cm) in diameter, is heated to a predetermined temperature, rapidly transferred to a jig fixture, and quenched, under standard conditions, by a jet of water impinging at one end. When the specimen is cool, determinations of hardness are made along it from the quenched end. The diagram relating hardness to distance from the quenched end of the specimen is known as a hardenability curve.