ISSN: 1945-7553
CODEN: JTEVAB
Page Count: 9

Fractographic Examination in the Scanning Electron Microscope as a Tool in Evaluating Through-Thickness Tension Test Results

McDonald, MM
Associate research engineer and associate research consultant, Research Laboratory, United States Steel Corp., Monroeville, PA

Ludwigson, DC
Associate research engineer and associate research consultant, Research Laboratory, United States Steel Corp., Monroeville, PA

Abstract

The through-thickness tension test is used to assess resistance to lamellar tearing. Observed through-thickness reduction-of-area (TTRA) values are usually well above the 20% minimum specification level in steels produced for lamellar-tearing-resistant applications. Low TTRA values, when encountered, indicate susceptibility to lamellar tearing but provide little indication of the source of premature fracture. Fractographic examination, especially with the scanning electron microscope, provides information about the origins of low ductility. Sources of premature fracture discussed herein are indigenous inclusions, exogenous inclusions, occluded hydrogen, undissolved alloy additions, and solidification microvoids.

Keywords:
fractography, tension tests, inclusions, through-thickness, fracture mode, microvoids, alloy additions, lamellar tearing, scanning electron microscopy, energy dispersive X-ray analysis, occluded hydrogen, fisheye

Paper ID: JTE10677J
DOI: 10.1520/JTE10677J
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