HEAT TREATMENT OF BRASS

• Main Authors: KAWATE KENJI, OZAWA KOUICHI
• Format: Patent
• Language: English
• Published: 20.12.1985
• Subjects: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS ANDNON-FERROUS ALLOYS; 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; FERROUS OR NON-FERROUS ALLOYS; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLICMATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASSC23 AND AT LEAST ONEPROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25; NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PURPOSE:To prevent the surface of brass from discoloring to copper color due to the dezincing reaction by performing the immersion zinc treatment to brass and thereafter performing the heat-treatment in which the dezincing is performed in the saturated vapor pressure and under of zinc vapor and evaporating the zinc contained in brass in the heat-treatment. CONSTITUTION:In the state that the inside of a heat-treating furnace 10 arranged with brass material 13 has been regulated to the protective gas atmosphere with the protective gas 1, the temp. of the furnace 10 is risen and the content of gaseous zinc is measured 4. Zinc vapor 8 is fed to the furnace 10 by controlling the divergence of a butterfly valve 9 via a driving means such as a servomotor. Thereby the immersion zinc treatment in which the content of zinc contained in the material 13 is enriched is performed. Then, while maintaining the temp. of the furnace 10, the valve 9 is completely closed to stop the feed of the zinc vapor 8 for the furnace 10. The vapor pressure of zinc in the furnace 10 is reduced to the saturated vapor pressure and under and in the protective gas atmosphere of the inside of the furnace 10, while preventing the oxidation of zinc, the material 13 is heat-treated and also the dezincing treatment is performed.