STP839

    Use of Image Analysis for Assessing the Inclusion Content of Low-Alloy Steel Powders for Forging Applications

    Published: Jan 1984


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    Abstract

    The extensive porosity present in pressed and sintered ferrous materials masks the effects of inclusions on the mechanical properties of these materials. In contrast, the properties of material powder forged to near theoretical density are strongly influenced by the composition, size distribution, and location of nonmetallic inclusions.

    A method is therefore required for assessing the cleanliness of iron and low-alloy steel powders intended for powder forging applications. Automatic image analysis techniques are preferred for use in this application, as they are not subject to operator sensitivity and can be used routinely to obtain a wider range of data. However, many of the inclusions found in water-atomized low-alloy powders have a relatively open, “lacy” appearance. In order to count such inclusions as single entities rather than numerous smaller particles, a special image analysis technique has been developed. This involves amendment of the detected video image using various combinations of image dilation, erosion, and reconstruction.

    Keywords:

    quantitative metallography, steels, image analysis, image amendment, nonmetallic inclusions, powder forging, low-alloy steel powders


    Author Information:

    James, WB
    Manager, Product Development, Hoeganaes Corp., Riverton, N.J.


    Paper ID: STP30217S

    Committee/Subcommittee: E04.09

    DOI: 10.1520/STP30217S


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