Method for the heat-treatment of steel and for the control of said treatment

摘要

The invention relates to a method of and an installation for the heat treatment of steels, such as heating before hardening, annealing, carburization and carbo-nitridation, carried out in a furnace in the presence of a protection or carbon-enrichment atmosphere which flows continuously through the furnace, the atmosphere being obtained by the mixture, before its introduction into the furnace, of a carrier gas including nitrogen and possibly hydrogen, and an active gas constituted by a hydrocarbon, the mixture containing at least 0.2% by volume of hydrocarbon.PPThe active gas may be constituted by ethylene, ethane or acetylene and the treatment is carried out at a temperature between 700° and 1050° C.PPThe installation includes a device for analyzing the atmosphere at the furnace outlet, this analyzer actuating a regulating valve for the inlet flow of active gas through a servo-mechanism, in dependence on the proportion of carbon in the treated steel.