A process for case hardening steel

• Main Authors: JAKUBOWSKI, THOMAS MICHAEL, WOOD, WILLIAM GEORGE
• Format: Patent
• Language: English; French; German
• Published: 15.09.1982
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

A process for case hardening steel is described. A fused bath of inert salt is provided which is comprised of alkali halides, alkali earth halides, or mixtures thereof, and alkali oxides, alkaline earth oxides, alkali carbonates, alkaline earth carbonates, or mixtures thereof. There is added to this fused bath, after suspending the steel therein, urea, dicyanodiamide, pyrolysis/condensation products of urea or dicyanodiamide, or combinations thereof. This will form active ions containing carbon and/or nitrogen, and either the nitrogen and/or carbon will diffuse into the surface of a steel piece suspended in the bath to form either a nitrided, carbonitrided or carburized case depending upon the temperature of the bath, which is selectively maintained between above 540 DEG C. and about 950 DEG C.