C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
C21D1/76—Adjusting the composition of the atmosphere
C—CHEMISTRY; METALLURGY
C21—METALLURGY OF IRON
C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
Procédé de protection principalement contre la cokéfaction des surfaces en alliage réfractaire en contact avec les réactifs dans des fours de pyrolyse et fours obtenus par ce procédé