STP1195

    Finite Element Modeling of Carburizing for Alloy Steels

    Published: Jan 1993


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    Abstract

    A finite element program has been developed to predict the distribution of carbon in carburized gears and bearings made from alloy steels. The finite element method was used because complicated shapes could be considered and because the same computer models could be applied to future studies on the formation of residual stresses during heat treatment.

    The program was developed using COSMOS/M, a commercial finite element code, on a Sun 3/60 workstation. The program considers the variation of carbon diffusivity with concentration and it accounts for carbide precipitation in a unique way. In addition, it can be applied to both conventional and vacuum carburizing.

    The program was tested by comparing its predictions with experimental measurements. The experiments involved carburizing an M50NiL specimen and measuring profiles of carbon concentration versus depth by electron microprobe. Profiles of total carbon (i.e., matrix + carbide) were obtained below both flat and curved surfaces, while below a flat surface a profile of matrix carbon was measured as well. The computer predictions involved first developing a one-dimensional model. The model was based on physical property data and two parameters that were adjusted to fit the profile measured below the flat surface. Then a two-dimensional model was developed using the same parameters, and compared with experimental profiles. The results illustrate the accuracy of the model at internal and external corners.

    Keywords:

    carburizing, finite element method, alloy steels, M50NiL


    Author Information:

    Dupen, BM
    Graduate student and professor, University of Connecticut, Storrs, CT

    Morral, JE
    Graduate student and professor, University of Connecticut, Storrs, CT

    Law, CC
    Senior research engineer, United Technologies Corporation, Pratt & Whitney, East Hartford, CT


    Paper ID: STP24824S

    Committee/Subcommittee: A01.28

    DOI: 10.1520/STP24824S


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