CAPSULE FOR HOT ISOSTATIC PRESSURIZATION MOLDING, ITS PRODUCTION AND HOT ISOSTATIC PRESSURIZATION MOLDING METHOD

摘要

PURPOSE:To produce a capsule having high internal cleanliness by forming the capsule for the isostatic pressurization molding to a specific shape and welding the capsule in an inert gaseous atmosphere, thereby producing the capsule. CONSTITUTION:The capsule to be used in the case of producing the mechanical parts for which particularly high strength and high reliability are demanded is made of mild steel plates, i.e., raw materials, and is temporally assembled to the shape which has a circular conical cap body 3 having 60-160 deg. vertical angle and a deaeration pipe 4 at the peak part 3b thereof in an upper aperture 2a of a cylindrical capsule body 2 having a bottom 2a. After this assembly is cleaned to completely remove the fats and oils and dust sticking thereto, the assembly is subjected to normal welding in a vessel in which an inert gas such as Ar is filled to the pressure higher than the atmospheric pressure to constitute the capsule having no oxide scale. Powder of an Ni-base super alloy, etc., is packed into this capsule 2 and the gas in the capsule is sucked and evacuated by the deaeration pipe 4. After such capsule is hermetically sealed by welding, the capsule is molded and sintered by the hot isostatic pressurization. The sintered mechanical parts contg. impurities at an extremely low ratio and having the excellent strength and reliability are produced.