Creep and creep-rupture behavior of ERNiCr-3 weld metal. [454 to 732/sup 0/C]

Technical Report · Thu Jun 01 00:00:00 EDT 1978

DOI:https://doi.org/10.2172/6549861· OSTI ID:6549861

Klueh, R. L.; King, J. F.

Creep and creep-rupture tests were made on AWS A5.14 Class ERNiCr-3 weld metal, commonly known as Inconel 82. Tests were made over the range 454 to 732/sup 0/C on specimens taken from welds made by the gas tungsten-arc process. The results fell into two categories: those for tests at 454, 510, and 566/sup 0/C displayed different characteristics than those at 621, 677, and 732/sup 0/C. At the lower temperatures the creep curves were characterized by a rapid transient, a long steady-state stage, and little tertiary creep. At the elevated temperatures the transient stage was not as rapid, the steady-state creep stage was shorter, and the tertiary stage was longer. The low-temperature creep-rupture curves and stress-minimum creep rate curves were also much flatter than those at the elevated temperatures. For certain tests at 454, 510, and 566/sup 0/C the creep curves exhibited an ''instantaneous elongation'' or ''strain burst'' phenomenon, in which the creep curves contained strain jumps. At these same temperatures, several specimens failed prematurely. Strain bursts are postulated to be related to the formation of dislocation pileups in the matrix. When a localized pileup breaks through a barrier, a dislocation avalanche results and triggers neighboring pileups continuing into neighboring grains giving rise to the propagation of a deformation band along the gage length in a Luder's-type deformation. It was proposed that the premature failures were related to the strain burst phenomenon and some scattered ''voids'' or ''cracks'' that were observed in the as-welded microstructure.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: Not Available; USDOE
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6549861
• Report Number(s): ORNL-5404
• Country of Publication: United States
• Language: English

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ALLOYS
BREEDER REACTORS
CHROMIUM ALLOYS
CLINCH RIVER BREEDER REACTOR
CRACKS
CREEP
CRYSTAL STRUCTURE
DEFORMATION
ELONGATION
EPITHERMAL REACTORS
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FILLER METALS
GRAIN BOUNDARIES
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JOINTS
LIQUID METAL COOLED REACTORS
MANGANESE ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
POWER REACTORS
REACTORS
SODIUM COOLED REACTORS
STRAIN RATE
TANTALUM ALLOYS
TEMPERATURE EFFECTS
TENSILE PROPERTIES
WELDED JOINTS