HIGH-SPEED ROTARY MEMBER AND SURFACE TREATMENT THEREOF

• Main Authors: OTSUKA KIMITERU, UENO TAISEI
• Format: Patent
• Language: English
• Published: 26.12.1990
• Subjects: ALLOYS; APPARATUS THEREFOR; BEARINGS; BLASTING; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; ELEMENTS OR CRANKSHAFT MECHANISMS; ENGINEERING ELEMENTS AND UNITS; FERROUS OR NON-FERROUS ALLOYS; FLEXIBLE SHAFTS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; LIGHTING; MECHANICAL ENGINEERING; 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; PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROMOBJECTS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; SHAFTS; THERMAL INSULATION IN GENERAL; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WEAPONS

PURPOSE:To provide the high-speed rotary member withstanding high load and high-speed rotation and having excellent performance by removing the sharp edge around the graphite in the surface layer of a ductile iron member to expose the graphite or embedding the graphite in a recess. CONSTITUTION:The sharp edge around the graphite 1 is removed to expose the graphite 1 on the surface by applying >=1 kind of treatment among chemical etching, electropolishing and electrolytic grinding to the surface layer of a ductile iron as the high-speed rotary member, or the graphite 1 is embedded in a recess. As a result, a base metal structure 2 from which the graphite 1 is exposed and the rounded edge 4 are formed. The area ratio of the pearlite in the surface layer of the rotary member is controlled to >=92% and the average grain diameter of the graphite to <=35mum, a ferrite ring is not present between the pearlite and graphite, and the dense base metal easy to grind is obtained. Since the base metal structure is thus improved, a member having the bearing performance comparable to that of a forged steel member is obtained.