STP1419: Development of 5280 Rolling Bearing Steel for Improved Performance and Productivity

    Dimitry, PV
    Mgr. Technical Service and Product Development and Mgr. Quality Assurance and Metallurgy, MACSTEEL®, Jackson, MI

    McDonough, PJ
    Mgr. Technical Service and Product Development and Mgr. Quality Assurance and Metallurgy, MACSTEEL®, Jackson, MI

    Beck, G
    Mgr. Laboratory and Research Engineer, FAG OEM und Handel AG, Schweinfurt

    Eberhard, R
    Mgr. Laboratory and Research Engineer, FAG OEM und Handel AG, Schweinfurt

    Zock, HW
    Director Research, New Materials Bayreuth Inc.,

    Pages: 24    Published: Jan 2002


    Abstract

    A new optimized steel analysis has been developed in which the carbon and chromium are reduced and the manganese increased to improve the solidification during continuous casting. The aim of this new grade is a steel far more suitable for continuous casting than 52100 (100Cr6).

    The bearing steel 52100 (100Cr6) has a proven track record throughout the world as the high carbon material of choice. With the increased production from the continuous casting process and the efficiencies of direct rolling, in combination with higher stress conditions for bearings, certain weaknesses have been recognized with the grade 52100 (100Cr6). Due to the high productivity rates of modern continuous casters, the long homogenizing cycles to minimize carbide segregation in 52100 are no longer practical. Without these long homogenizing cycles the result is more pronounced forms of segregation and adverse carbide distributions. These disadvantages can result in restricted mechanical and thermo-mechanical physical properties leading to difficulties in conventional and induction heat treatments.

    The new grade under development can be classified 5280 (80CrMn4) and has been evaluated from both the steel production aspects as well as metallurgical behavior. With regard to the decisive properties of microstructure, life and processing the 5280 (80CrMn4) was equivalent to or better than the 52100 (100Cr6) steel. Continuous casting improved significantly; porosity, cracks or cavities were not present. The carbon segregation index was reduced. Carbide distributions measured according to SEP 1520 were at a minimum level, without excessive soaking prior to direct rolling. Heat treatment response was slightly modified to lower quenching temperatures, tempering at 220°C and 240°C resulted in the same values for hardness and retained austenite as in the case of 52100 (100Cr6). After martcnsitic heat treatment the hardness stabilization in 5280 (80CrMn4) required no process change from 52100 (100Cr6) to achieve the same degree of stabilization.

    Mechanical properties of tensile strength, impact bending and notch impact strength; wear resistance and rotating bending strength were evaluated with direct comparisons to 52100 (100Cr6). Rolling contact fatigue tests were carried out on angular contact ball bearings of type 7205B where the inner rings were the test specimens. Test conditions were selected in such a way that it would be possible to make comparisons with 52100 (100Cr6) under diverse types of stress. The fatigue life of the 5280 (80CrMn4) was equivalent to the 52100 (100Cr6) base data.

    Keywords:

    through-hardening bearing steel, rolling contact fatigue, mechanical properties


    Paper ID: STP10843S

    Committee/Subcommittee: A01.28

    DOI: 10.1520/STP10843S


    CrossRef ASTM International is a member of CrossRef.