STP1425: Fretting Fatigue Properties of WC-Co Thermal Sprayed NiCrMo Steel

    Okane, M
    Research Associate, Toyama University, Toyama,

    Shiozawa, K
    Professor, Toyama University,

    Hiki, M
    Graduate Student, Toyama University,

    Suzuki, K
    Executive Director, Ohsuzu Giken Co. Ltd., Hamamatsu,

    Pages: 15    Published: Jan 2003


    Abstract

    Fretting fatigue tests of NiCrMo steel (JIS SNCM439) sprayed with ungsten carbide with additive of 12% cobalt (WC-Co) by HVOF (High Velocity Oxygen Fuel) were carried out to study the effect of WC-Co coating on fretting fatigue behavior. Since the fatigue strength of the present alloy steel was reduced to about 27% by the effect of fretting, fretting fatigue strength was improved by approximately 30% by WC-Co spraying onto the specimen. The tangential force coefficient, which is tangential force measured during the fretting fatigue tests divided by contact load, behaviors of WC-Co sprayed specimen were different form those of the non-sprayed specimen. Especially, the tangential force of WC-Co specimen in an early stage of the test indicated significant low value compared with that of non-sprayed specimen and this was caused from good wear resistance of WC-Co layer. Therefore, the initiation of a fretting crack in case of WC-Co sprayed specimen delayed, and crack propagation rate was lower than that of non-sprayed specimen. These were main reasons for the improvement of fretting fatigue strength by WC-Co spray.

    Keywords:

    fretting fatigue, NiCrMo steel, spray, WC-Co, HVOF, fretting wear


    Paper ID: STP10772S

    Committee/Subcommittee: E08.03

    DOI: 10.1520/STP10772S


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