Galling wear of cobalt-free hardfacing alloys. Final report
Cobalt-base alloys have been used as hardfacing materials for nuclear power plant valves, turbines and pumps. In nuclear power plants cobalt is transported to reactor core region due to wear of valves and pumps; it is transmuted to Co{minus}60. Objective of this work was to find a cobalt-free hardfacing material that has better wear-resistance than the widely used cobalt-base alloy Stellite 6{sup TM} Six iron-base and four nickel-base alloys were compared to Stellite 6. The alloys were deposited on austenitic stainless steel by GTAW (Gas Tungsten Arc Welding), PTAW (Plasma Transferred Arc Welding), plasma spray fuse and laser processes. One alloy was in HIP (Hot Isostatic Pressed) condition. All alloys were tested for galling resistance in air at room temperature at applied stresses were 140, 275 and 415 MPa. Alloy microstructure and hardness values were post-test wear surfaces, were examined using a light and scanning electron microscopy, and microhardness measurements. Crack-free deposits can be manufactured from all of the alloys, and no problems were encountered during machining of the deposits. Self-mated galling resistance of Stellite 6 was comparable to galling resistance in earlier studies for this alloy. Self-mated iron-base Elmax, APM 2311, NOREM A, Nelsit, Everit 50 So alloys and Ni-/Fe-base alloy combination showed significantly better galling behaviour than Stellite 6, especially Elmax and APM 2311 alloys. Nickel-base Deloro alloys showed galling resistance inferior to Stellite 6. No correlation was observed between the microstructural characteristics and galling resistance. Further, the galling resistance is not related to the hardness of the deposit.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (United States); ABB Atom AB, Vaesteraas (Sweden)
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 10159620
- Report Number(s):
- EPRI-TR-103845; ON: UN94013647; TRN: 94:011164
- Resource Relation:
- Other Information: PBD: May 1994
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
22 GENERAL STUDIES OF NUCLEAR REACTORS
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
HARD FACING
NUCLEAR POWER PLANTS
REACTOR COOLING SYSTEMS
MATERIALS
IRON BASE ALLOYS
WEAR RESISTANCE
NICKEL BASE ALLOYS
BWR TYPE REACTORS
PUMPS
VALVES
TURBINES
STELLITE 6
360105
220200
210100
CORROSION AND EROSION
COMPONENTS AND ACCESSORIES
POWER REACTORS
NONBREEDING
LIGHT-WATER MODERATED
BOILING WATER COOLED