Vacuum heat treatment and brazing of metallic materials

Abstract

Vacuum heat treatment is applicable to most common metals. Vacuum heat treating processes show a distinct advantage over conventional processes in that vacuum heat treatment obtains a bright surface free of defects such as decarburization and intergranular oxidation. Distortion of the parts normally occuring during conventional processing is minimized in vacuum. Parts may therefore be processed in the fully machined condition. Vacuum furnace brazing renders the use of flux unnecessary; it allows the use of a wide variety of brazing filler metals; improves the physical properties of the joint by eliminating such defects as porosity and oxide inclusions; it enables the successful brazing of the nickel and cobalt base superalloys, a difficult task to achieve by conventional means. A cost comparison between vacuum and conventional heat treating processes indicates that vacuum is the most economical method of processing. The paper intends to relate the above to actual processes and to indicate where considerable savings in labour and time may be obtained by the application of vacuum processing.