Abstract: This invention relates to a method of heat-treating steel in a furnace in the presence of a controlled atmosphere.The H.sub.2 O content of the furnace is determined, the atmosphere is formed by adding to a carrier gas a quantity of a hydrocarbon having the general formula C.sub.x H.sub.y which is necessary and sufficient to reduce the water in the furnace in accordance with the following reaction:C.sub.x H.sub.y +xH.sub.2 O.fwdarw.xCO+(x+y/2)H.sub.2,and the steel is raised to a temperature between 650.degree. and 900.degree. C.The method is applicable to the annealing, heating before quenching, and tempering of steel.

Abstract: The invention relates to a method of and an installation for the heat treatment of steels, such as heating before hardening, annealing, and carburization, which heat treatment is 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.The active gas may be constituted by ethylene, ethane or acetylene and the treatment is carried out at a temperature between 850.degree. and 1050.degree. C.The 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.

Abstract: 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.The active gas may be constituted by ethylene, ethane or acetylene and the treatment is carried out at a temperature between 700.degree. and 1050.degree. C.The 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.