Characterization of solidification and weldability of Fe-29Ni-17Co alloys
Applications for the controlled thermal expansion alloy Fe-29Ni-17Co often require joining by fusion welding processes. In addition, these applications usually require hermetic and high reliability joints. The small size of typical components normally dictates the use of autogenous welding processes, so that the hot cracking tendency of Fe-29Ni-17Co is of concem. The solidification behavoir and hot cracking tendency of commercial Fe-29Ni-17Co has been evaluated using diffcrential thermal analysis (DTA), Varestraint testing, light and electron microscopy, and laser welding trials. DTA and microstructural analysis indicated that the solidification of Fe-29Ni-17Co occurs as single phase austenite, does not exhibit the formation of terminal solidification phases, and results in only minimal segregation of major alloying elements. Varestraitit testing indicated that the hot cracking behavior of Fe-29Ni-17Co is similar to, though somewhat more pronounced than, 304L and 316 stainless steels. Relative to other Fe-Ni-Co and Ni-based alloys, however, the hot cracking response of this alloy is fiverable. Pulsed laser welding trials indicated that the phosphorus and sulfur levels in this heat of Fe-29Ni-17Co were insufficient to pmmote cracking in bead-on-plate welds.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- OSTI ID:
- 6987490
- Report Number(s):
- SAND-92-1958C; CONF-921109--2; ON: DE93000739
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360101* -- Metals & Alloys-- Preparation & Fabrication
ALLOYS
COBALT ALLOYS
CRACKS
CRYSTAL STRUCTURE
FABRICATION
IRON ALLOYS
IRON BASE ALLOYS
JOINING
LASER WELDING
MICROSTRUCTURE
NICKEL ALLOYS
PHASE TRANSFORMATIONS
PHOSPHORUS ADDITIONS
SOLIDIFICATION
SULFUR ADDITIONS
WELDABILITY
WELDING