Accession Number : AD0649137

Title :   A STUDY OF HOT CRACKING IN WELDED HIGH-STRENGTH STEELS USING THE VARESTRAINT TEST.

Descriptive Note : Research and development phase rept.,

Corporate Author : NAVY MARINE ENGINEERING LAB ANNAPOLIS MD

Personal Author(s) : Thompson,R. E.

Report Date : MAR 1967

Pagination or Media Count : 49

Abstract : Hot cracking of HY-130/150 steel and a rare-earth-treated HY-80 steel during welding was investigated with the Varestraint test apparatus, a device which permits independent variation of welding conditions and restraint. The test involves depositing a weld bead and simultaneously applying an instantaneous bending load. The susceptibility of a material to hot cracking is determined from the resulting amount of cracking. Two welding processes were used on thin plate specimens: tungsten-inert-gas without filler, and metal-inert-gas. Results showed that the amount of hot cracking varied with welding conditions, plate thickness, and applied strain. The data indicated HY-130/150 to be more resistant to cracking than HY-80. Cracking occurred at solute-enriched grain boundaries, but not at substructure boundaries. Segregation and structural features of boundaries were found to be important factors associated with hot cracking. Examination of the metal-inert-gas welds revealed evidence of capillary diffusion of solute into hot cracks.

Descriptors :   (*CRACK PROPAGATION, STEEL), (*STEEL, WELDING), CRACKS, WELDS, MICROSTRUCTURE, GRAIN BOUNDARIES, SUBMARINE HULLS, METAL PLATES, STRAIN(MECHANICS), METALLOGRAPHY

Subject Categories : Properties of Metals and Alloys
      Fabrication Metallurgy
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE