F. Chaffotte, P. Levée, D. Domergue, Air Liquide, Jouy en josas Cedex, France; A. Goldsteinas, ECM, Grenoble, France; J. Y. Weïté, Thermie Bourgogne Industrie, Chevigny Saint Sauveur, France

Summary: Thanks to its environmental advantages, high pressure gas quenching is a developing technology for carburising grades, in particular when associated to low-pressure carburising such as for parts used in automotive applications. However this promising technology faces relatively low cooling rates compared to more common quenching media such as oil baths. This becomes critical for application to low-hardenability steel grades and large cross-section parts. Optimisation of gas mixture with respect to increase of heat transfer has been demonstrated and applied at test scale in a former study [1]. This paper addresses the application of this new gas quenching process at industrial scale. Performance results are given in particular for low-hardenability steel grades and large cross-section industrial parts. Equipment issues are also presented including Air Liquide gas recycling equipment connected to ECM low-pressure carburising and high pressure gas quenching furnace.