The performance of welded structures is closely associated with the ductile-to-brittle transition temperature of the steel from which they are made. A low transition temperature is desirable because it indicates that the steel is less likley to fail suddenly at low ambient temperatures. Structures such as bridges, ships, storage tanks, and pipelines are usually made from hot rolled semikilled steel. Changes in rolling practice or chemical composition appear to be the most practical methods for improving the toughness of such materials. This results from the fact that production is likely to be seriously curtailed if improvements were obtained by recourse to heat treatment or complete deoxidation. This paper discusses the effect of variations in carbon and manganese contents on the properties of semikilled steels. The transition temperature, a property to which considerable importance is attached, varies with specimen configuration, testing method, and criterion of performance. Both the Navy tear test and the keyhole Charpy test were used in the investigation. According to the terms used by Vanderbeck and Gensamer, the tear test was used to measure a fracture transition and the Charpy test to measure a ductility transition. In either case the specimens absorb considerably less breaking energy in tests below the transition temperature than in tests above the transition temperature. Decreasing the testing temperature of notched-bar specimens seems to be equivalent in its effect to increasing the severity of loading on fabricated structures. Therefore, structures built from steels exhibiting lower transition temperatures in laboratory tests are expected to be less susceptible to sudden brittle fractures in service. Consequently, changes in composition which lowered the transition temperature of the experimental steels were judged desirable.

  • Corporate Authors:

    Battelle Memorial Institute

    505 King Avenue
    Columbus, OH  United States  43201

    Ship Structure Committee

    National Academy of Science, 2101 Constitution Avenue, NW
    Washington, DC  United States  20418
  • Authors:
    • Boulger, F W
    • Frazier, R H
    • Lorig, C H
  • Publication Date: 1954-10-28

Media Info

  • Pagination: n.p.

Subject/Index Terms

Filing Info

  • Accession Number: 00331285
  • Record Type: Publication
  • Source Agency: Ship Structure Committee
  • Report/Paper Numbers: SSC- 82 Prog Rpt.
  • Contract Numbers: NObs-53239
  • Files: TRIS
  • Created Date: May 21 1981 12:00AM