The Mechanical Characterization of Low Work Hardening, High Strength Steel

    Volume 2, Issue 9 (October 2005)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Page Count: 15


    Scott, RI
    School of Engineering and Technology, Deakin University, Geelong,

    Hodgson, PD
    School of Engineering and Technology, Deakin University, Geelong,

    (Received 27 May 2005; accepted 22 July 2005)

    Abstract

    One of the major challenges in assessing the mechanical properties of recovery annealed steel is the strain localization that occurs almost immediately on the formation of the first Lüders band, such that no or limited propagation of the Lüders band occurs along the tensile coupon. The stress raiser associated with the geometry of the standard tensile coupon means that this plastic deformation is often completely outside the standard extensometers on the coupon. Hence, no strain is measured during the test. While this is not important for assessing the tensile strength of the steel, it does mean that the strain related properties, such as the elastic limit of the steel, cannot be measured using standard testing techniques.

    This work addresses this issue by examining three techniques for ensuring that the strain occurs inside the extensometer. It is shown that the best technique is the extended extensometer, where the gauge length covers slightly more than the tensile coupon parallel length. While this leads to some variation in the width of the material being measured, compensation can be made by adjusting the strain to correct the Young's Modulus.

    This technique has direct implications not just for recovery annealed steels, but for other high strength, low work hardening materials such as ultrafine ferrite. A particular requirement of these high strength steels in structural applications is a high elastic limit; hence, measurement of the strain related properties for these high strength materials must be considered vital in their mechanical assessment.


    Paper ID: JAI14145

    DOI: 10.1520/JAI14145

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    Author
    Title The Mechanical Characterization of Low Work Hardening, High Strength Steel
    Symposium , 0000-00-00
    Committee A01