STP644

    Alloy Steels for High-Strength, As-Rolled Rails

    Published: Jan 1978


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    Abstract

    A laboratory study was conducted on a broad range of compositional variations of chromium-molybdenum steels for application as high-strength, as-rolled rails. A series of experimental heats was prepared and processed to simulate commercial production of as-rolled 65-kg/m (132-lb/yd) rail, with regard to cooling rate and transformation characteristics. Test specimens were evaluated in terms of hardness, tensile properties, and microstructure. The mechanical properties are related to the observed microstructures. Increasing the molybdenum content of the steel is highly effective in increasing yield strength by refining the pearlite; the appearance of coarse bainite reduces the yield strength. Vanadium contributes additional strengthening, but only under certain conditions where the pearlite is refined. Lowering carbon and adding columbium produces microstructural changes that are not beneficial to the mechanical properties. These results make possible some tentative conclusions regarding the optimization of composition for the commercial production of as-rolled rails in the 760 to 1170 N/mm2 (110 to 170 ksi) yield strength range.

    Keywords:

    steels, railroad tracks, high strength steels, mechanical properties, microstructure, pearlite, molybdenum alloys


    Author Information:

    Smith, YE
    Research supervisor and senior research associate, Climax Molybdenum Company, Ann Arbor, Mich

    Fletcher, FB
    Research supervisor and senior research associate, Climax Molybdenum Company, Ann Arbor, Mich


    Paper ID: STP27110S

    Committee/Subcommittee: A01.01

    DOI: 10.1520/STP27110S


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