STP794

    Some Effects of Specimen Design, Sample Location, and Material Strength on Through-Thickness Tensile Properties

    Published: Jan 1983


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    Abstract

    The percent reduction of area for tension specimens made in the through-thickness direction of plates (%RAZ) is often determined to give a relative measure of the resistance to lamellar tearing. Testing variables can affect the %RAZ measured. Results are presented of investigations designed to examine some effects of (1) tension specimen design, (2) specimen location relative to the original ingot, (3) steel microstructure, (4) material strength level, (5) specimen-to-specimen variability, and (6) final diameter measurement reproducibility. Tension specimens in the Z-direction with an 8.9 mm (0.350 in.) diameter and 50.8 to 63.5 mm (2 to 212 in.) parallel section gave the highest average %RAZ and smallest variability. Specimen location had a very marked effect on the %RAZ, with the lowest values found along the ingot centerline and highest levels at the ingot corners and edges. Normalized ASTM A537 Class 1 steel gave higher %RAZ than when quenched and tempered to nearly the same ultimate tensile strength. Material strength level varied by changing the tempering temperature after quenching had only a small effect on the %RAZ. Considerable specimen-to-specimen variability in the %RAZ can exist even within a small area of a plate and reduce the significance of a single specimen result. Final specimen diameters can be difficult to measure and reproducibility of the %RAZ calculated by different testing personnel for an individual specimen is sometimes poor.

    Results indicate that specifications covering the through-thickness tension testing of roiled steel plates should reference the test location to the original as-cast ingot or slab if the region of lowest %RAZ is to be reported. Specifications need to address the problem of specimen-to-specimen variability and %RAZ reproducibility when determining the number of specimens to be tested and establishing acceptance criteria.

    Keywords:

    through-thickness tension test, reduction of area, lamellar tearing, plates, tension testing variables, material variables


    Author Information:

    Jesseman, RJ
    Senior Research Metallurgist, Research and Technology, Armco Inc., Middletown, Ohio

    Murphy, GJ
    Supervising Metallurgist, Southwestern Steel Division, Armco Inc., Houston, Tex.


    Paper ID: STP10014S

    Committee/Subcommittee: A01.11

    DOI: 10.1520/STP10014S


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