STP771: Effect of Test Variables on the Rolling Contact Fatigue of AISI 9310 and VASCO X-2 Steels

    Lamothe, RM
    Supervisory materials engineer and electronics engineer, Army Materials and Mechanics Research Center, Watertown, Mass.

    Zagaeski, TF
    Supervisory materials engineer and electronics engineer, Army Materials and Mechanics Research Center, Watertown, Mass.

    Cellitti, R
    Managers, Metallurgical Process Research, International Harvester Co., Hinsdale, Ill.

    Carter, C
    Managers, Metallurgical Process Research, International Harvester Co., Hinsdale, Ill.

    Pages: 14    Published: Jan 1982


    Abstract

    An investigation of two gear steels, AISI 9310 and VASCO X-2, carburized to a depth of 1.524 mm, was conducted to evaluate the effect of materials processing parameters on the fatigue lives of these materials in rolling contact fatigue, in single-tooth bending fatigue, and, finally, in a four-square dynamometer gear testing fixture. The study was carried on simultaneously at the International Harvester Co. (IH) and the Army Materials and Mechanics Research Center (AMMRC).

    Rolling contact fatigue (RCF) was performed on two types of RCF machines which yielded different mean lives for each material. The RCF testing at IH was done on a machine designed to produce a 30 percent negative slippage at a contact stress magnitude of 3102 MPa (1 MPa = 145 psi). The AMMRC RCF tests, on the other hand, were conducted on a machine designed primarily for evaluating the fatigue life of ball bearings and had no provisions for including slippage. The magnitude of the contact stress obtained in the AMMRC tests was adjusted to 5171 MPa.

    The mean fatigue life of VASCO X-2 in comparison to AISI 9310, was approximately five times greater at the B50 mean life on data generated with the IH machine. The higher fatigue life of VASCO X-2 was attributed to surface carbides and retained austenite. However, data generated on the AMMRC apparatus indicated the reverse, that is, the mean life of AISI 9310 steel was greater than that of VASCO X-2. Rationales for the observed differences in mean lives between the different materials and between the results of the two testing apparatuses are presented.

    Keywords:

    rolling contact fatigue, steel, AISI 9310 steel, VASCO X-2 steel, bearing steels


    Paper ID: STP36151S

    Committee/Subcommittee: A01.28

    DOI: 10.1520/STP36151S


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