STP794

    Effect of Specimen Type on Reduction-of-Area Measurements

    Published: Jan 1983


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    Abstract

    Because the susceptibility of plate material to lamellar tearing is believed to be related to the amount of reduction of area measured by a tension test specimen oriented in the through-thickness (Z) direction, tests were conducted to determine the influence of specimen dimensions on the tensile properties of ASTM A36, A588, and A514 Grade F steels for the two types of specimens commonly used for testing in the Z-direction. The first is the standard specimen with the length of the reduced section shortened so that the overall length of the specimen is equal to the thickness of the plate (stub specimen). The second is the standard specimen machined from a blank that has been prepared by welding prolongations to the plate surfaces so that the plate forms a full-plate-thickness insert at the midlength of the specimen (tab specimen). Because the intent was to compare only the trends in the changes of the tensile strength values and the reduction-of-area values for the different specimens, and because variability obtained in the longitudinal direction is less than that obtained in the through-thickness direction, the specimens were oriented in the longitudinal direction of the plate.

    The results indicated a significant decrease in the reduction of area and a significant increase in the tensile strength of both types of specimens as the thickness of the insert or the length of the reduced section is decreased to less than two specimen diameters. These trends are due to constraint in plastic flow caused by the higher strength of the weld area of the tab specimens or by the shoulders of the stub specimens.

    Keywords:

    lamellar tearing, materials testing, reduction-of-area measurements, steel plates, tensile strength, tension test, test methods


    Author Information:

    Holt, JM
    Associate Research Consultant, Research Laboratory, U.S. Steel Corporation, Monroeville, Pa.


    Paper ID: STP10003S

    Committee/Subcommittee: A01.02

    DOI: 10.1520/10003S


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