STP794: Plate Thickness and Specimen Size Considerations in Through-Thickness Tension Testing

    Ludwigson, DC
    Associate Research Consultant, Research Laboratory, U.S. Steel Corporation, Monroeville, Pa.

    Pages: 11    Published: Jan 1983


    Abstract

    The through-thickness tension test to assess the resistance of plate steels to lamellar tearing often involves the welding of prolongs to either surface of coupons from a plate and the preparation of round through-thickness tension test specimens from the resulting weldments. Specimens are strained to failure in a universal testing machine, and reduction of area is calculated from before-and-after test measurements of minimum specimen diameter.

    Experiments have been performed to evaluate the influence of coupon thickness on tensile properties measured with axisymmetric through-thickness specimens prepared from stud-welded assemblies. Results indicate that the influence of coupon thickness on tensile strength and reduction of area is small, provided that the separation between metallographically observable weld heat-affected zones in the coupon is at least as great as the specimen diameter. At smaller separations the intrusion of hardened prolongs and associated welds into the specimen gage length severely increases observed tensile strength and severely decreases observed reduction of area.

    Test results led to an engineering rule of thumb for the minimum plate thickness that may properly be tested with welded through-thickness specimens of a given diameter:

    minimum plate thickness = specimen diameter + 2 (penetration distance)

    For a stud-welded specimen in which the penetration distance is about 0.457 mm (0.18 in.), the approximate minimum critical coupon thicknesses for 12.83, 9.07, and 6.40 mm (0.505, 0.357, and 0.252 in.) diameter specimens are 22.2, 19.1, and 15.9 mm (78, 34 and 58 in.), respectively. Provided these minimums are observed, property differences attributable to specimen size are small.

    Keywords:

    plate, lamellar tearing, ductility, through-thickness tension test, specimen size


    Paper ID: STP10006S

    Committee/Subcommittee: A01.02

    DOI: 10.1520/STP10006S


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