INFLUENCE OF THERMAL CUTTING AND ITS QUALITY ON THE FATIGUE STRENGTH OF STEEL

Structures are often fabricated by assembling and welding components that have been thermally cut from steel plate. It is therefore important to know how the quality of the thermal cutting affects the fatigue strength of dynamically loaded structural members. This investigation tested plate specimens grouped in five series according to quality of cut, as follows: machined, high quality oxygen cut, normal quality oxygen cut, low quality oxygen cut and normal quality plasma-arc cut. A few specimens with defects were also tested. The fatigue testing results were plotted in Wohler (S-N) diagrams which show that there is nearly a linear relation between surface roughness and fatigue strength. The plasma cut specimens had a fatigue strength comparable with machined specimens. Defects in the thermal cut surfaces had a strong negative influence on fatigue strength. High quality thermal cut specimens had a fatigue strength that was 80% of the yield stress, while low quality specimens had a fatigue strength 60% of the yield stress. Microstructural examination showed that the serrations caused by the oxygen cutting jet consists mainly of carburized material. Microhardness measurements showed that there is a soft zone just behind the hard carburized material on the surface. This 50 mu m wide zone has not been observed before.

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  • Supplemental Notes:
    • Presented at the 54th A.W.S. Annual Meeting, Chicago, Ill., April 2-6, 1973.
  • Corporate Authors:

    American Welding Society

    345 East 47th Street
    New York, NY  USA  10017
  • Authors:
    • GOLDBERG, F
  • Publication Date: 1973-9

Media Info

  • Pagination: p. 392-404
  • Serial:
    • Welding Journal
    • Volume: 52
    • Issue Number: 9
    • Publisher: American Welding Society
    • ISSN: 0043-2296

Subject/Index Terms

Filing Info

  • Accession Number: 00048111
  • Record Type: Publication
  • Source Agency: American Welding Society
  • Files: TRIS
  • Created Date: Oct 31 1973 12:00AM