Optimized Gen-II FeCrAl cladding production in large quantity for campaign testing

Technical Report · Fri Jun 03 00:00:00 EDT 2016

DOI:https://doi.org/10.2172/1257911· OSTI ID:1257911

Yamamoto, Yukinori ^[1]; Sun, Zhiqian ^[1]; Pint, Bruce A. ^[1]; Terrani, Kurt A. ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

There are two major objectives in this report; (1) to optimize microstructure control of ATF FeCrAl alloys during tube drawing processes, and (2) to provide an update on the progress of ATF FeCrAl tube production via commercial manufacturers. Experimental efforts have been made to optimize the process parameters balancing the tube fabricability, especially for tube drawing processes, and microstructure control of the final tube products. Lab-scale sheet materials of Gen II FeCrAl alloys (Mo-containing and Nb-containing FeCrAl alloys) were used in the study, combined with a stepwise warm-rolling process and intermediate annealing, aiming to simulate the tube drawing process in a commercial tube manufacturer. The intermediate annealing at 650ºC for 1h was suggested for the tube-drawing process of Mo-containing FeCrAl alloys because it successfully softened the material by recovering the work hardening introduced through the rolling step, without inducing grain coarsening due to recrystallization. The final tube product is expected to have stabilized deformed microstructure providing the improved tensile properties with sufficient ductility. Optimization efforts on Nb-containing FeCrAl alloys focused on the effect of alloying additions and annealing conditions on the stability of deformed microstructure. Relationships between the second-phase precipitates (Fe₂Nb-Laves phase) and microstructure stability are discussed. FeCrAl tube production through commercial tube manufacturers is currently in progress. Three different manufacturers, Century Tubes, Inc. (CTI), Rhenium Alloys, Inc. (RAI), and Superior Tube Company, Inc. (STC), are providing capabilities for cold-drawing, warm-drawing, and HPTR cold-pilgering, respectively. The first two companies are currently working on large quantity tube production (expected 250 ft length) of Gen I model FeCrAl alloy (B136Y3, at CTI) and Gen II (C35M4, at RAI), with the process parameters obtained from the experimental efforts. The expected delivery dates are at the end of July, 2016, and the middle of June, 2016, respectively. Tube production at STC would be the first attempt to apply cold-pilgering to the FeCrAl alloys. Communication has been initiated, and the materials have been machined for the cold-pilgering process.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1257911
• Report Number(s): ORNL/TM-2016/227; AF5810000; NEAF278; TRN: US1601501
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
IRON BASE ALLOYS
CHROMIUM ALLOYS
ALUMINIUM ALLOYS
MOLYBDENUM ALLOYS
NIOBIUM ADDITIONS
ACCIDENT-TOLERANT NUCLEAR FUELS
DRAWING
DUCTILITY
TUBES
ANNEALING
FUEL CANS
ROLLING
MICROSTRUCTURE
MANUFACTURERS
STRAIN HARDENING
CONTROL
PRECIPITATION
STABILITY
LAVES PHASES
OPTIMIZATION
SHEETS
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K