METALLURGICAL QUALITY OF STEELS USED FOR HULL CONSTRUCTION. FINAL AND SUMMARY REPORT

A study of twenty commercial HTS type steels showed that, in general, the steels with higher chemical composition were the most susceptible to underbead cracking, but frequently the variations in crack sensitivity found in different lots of steel could not be accounted for on the basis of chemical analysis, hardness of the heat-affected zone, hardenability, or the other properties commonly determined. Further study of these commercial steels showed that thermal processing had a pronounced influence upon the underbead cracking or crack sensitivity, the sensitivity being increased by annealing and decreased by homogenizing. In the case of similar chemical compositions, the level of crack sensitivity was found to increase with the degree of microsegregation. Homogenizing treatments, therefore, which decreased the extent of microsegregation, lowered the crack sensitivity, while annealing, which produced pearlite bands superimposed upon the alloy bands, increased the underbead cracking. Although the crack sensitivity of plate can be reduced to a marked degree by homogenizing at 2350 deg F for a relatively short period, such a treatment is not commercially feasible because of the excessive scaling and warping that would occur to the finished product. Homogenizing the slabs prior to rolling into plate was found to be impractical because of the excessive time required. A good correlation was found between the crack sensitivity and the depth of complete transformation in the heat-affected zone when expressed as per cent of the total depth of the affected zone under the weld bead. The purpose of this investigation, which concerns high-tensile plate steel (HTS type) used in the construction of welded ship hulls, was twofold, the first part being an investigation of the metallurgical quality with special attention being given to those factors which might influence the welding characteristics and the performance of the welded structure. The second part of the project covers the development of higher strength steels suitable for welded structures.

  • Corporate Authors:

    Battelle Memorial Institute

    505 King Avenue
    Columbus, OH  USA  43201

    Ship Structure Committee

    National Academy of Science, 2101 Constitution Avenue, NW
    Washington, DC  USA  20418
  • Authors:
    • Sims, C E
    • Banta, H M
    • Walters, A L
  • Publication Date: 1949-6-8

Media Info

  • Features: References;
  • Pagination: 115 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00330981
  • Record Type: Publication
  • Source Agency: Ship Structure Committee
  • Report/Paper Numbers: SSC- 26
  • Contract Numbers: NObs-31219, NObs-34231
  • Files: TRIS
  • Created Date: May 21 1981 12:00AM