Quench cracking in steel as a case of hydrogen embrittlement

The quench cracking that occurs in steels with carbon contents greater than about 0.3 wt% when the steel is austenitized and quenched into water is shown here to require contact of water with the surface of the steel. It can be avoided by first plating the steel with nickel. The appearance of the fracture surface of a quench crack is identical with that of a similar steel that has suffered hydrogen-induced cracking. It is concluded that quench cracking emanates from hydrogen released by the breakdown of water molecules that contact the steel surface.