CRACKING MECHANISMS IN HY-130 STEEL WELDMENTS

The objective of this research was to study the causes and mechanisms of cracking in HY-130 steel weldments. The various modes of crack initiation were investigated by use of a high temperature tensile test with a GLEEBLE device. The fractured surfaces were examined metallographically by use of the scanning election microscope. The results were then compared to cracks found in the metallographic examination of a circular fillet welded specimen. Cracking was found to be a three-stage phenomena. Intergranular cracks form in the heat affected zone of the weld at or near the fusion line where the temperature is just below the melting temperature. These intergranular cracks intersect with sulfide inclusions which appear at the grain boundaries as the temperature decreased and the grain distortion increased. The sulfide inclusion appears to act as a plastic hinge causing further cracking to extend transqranularly. The actual welding cycle employed appears to have little influence on the severity of the cracking process. A proposal is offered to reduce the probability of cracking by reducing the size of the sulfide inclusions.

  • Corporate Authors:

    Massachusetts Institute of Technology

    Department of Ocean Engineering, 77 Massachusetts Avenue
    Cambridge, MA  USA  02139
  • Authors:
    • Becker, A R
  • Publication Date: 1973-6

Subject/Index Terms

Filing Info

  • Accession Number: 00048376
  • Record Type: Publication
  • Source Agency: Massachusetts Institute of Technology
  • Report/Paper Numbers: Thesis
  • Files: TRIS
  • Created Date: Nov 14 1973 12:00AM