Hastelloy N
Hastelloy N (UNS N10003) is a nickel-molybdenum-chromium alloy (nominal 71% Ni, 16% Mo, 7% Cr, 5% Fe) originally developed at Oak Ridge National Laboratory under the designation INOR-8 for the Molten Salt Reactor Experiment (MSRE). It is the only standard commercial alloy with demonstrated resistance to corrosion by molten fluoride salt systems at temperatures up to 1300°F (704°C), making it the material of choice for advanced molten salt nuclear reactors, thorium fuel cycle systems, and fluoride-based chemical processing equipment.
In addition to its unique fluoride salt resistance, Hastelloy N has excellent oxidation resistance in air to 1800°F (982°C), good resistance to mineral acids, and high tensile strength at temperatures up to 1300°F. AMS 5786 governs the aerospace and premium-grade bar and forging form used in critical chemical processing and advanced energy applications.
Product Forms & Size Range of Hastelloy N
Hastelloy N bar, forgings, and tubing per AMS 5786 are available in round bar diameters from 0.375 inch to 6.000 inches and as forging stock. Bar is supplied solution annealed for machining of pump and valve components, heat exchanger headers, and pressure vessel fittings for high-temperature molten salt and fluoride chemical service. Tubing for heat exchanger bundle applications is available in a range of outside diameters and wall thicknesses.
HEAT TREATMENT OF HASTELLOY N
Hastelloy N is solution annealed at 2150–2200°F (1177–1204°C) followed by rapid quenching to produce a fully solutioned structure with maximum corrosion resistance and ductility. The alloy is not precipitation hardenable. An aging treatment at 1250°F (677°C) for 16 hours is sometimes specified for reactor-grade material to optimize elevated-temperature strength for pressurized molten salt service. Post-weld annealing at 2100°F (1149°C) restores corrosion resistance in the weld heat-affected zone.
Hastelloy S
Ni-Cr-Mo alloy with excellent high-temperature oxidation resistance and low thermal expansion — used for gas turbine combustion zone components.
Haynes Alloy 230
Ni-Cr-W-Mo alloy for combustion liners and gas turbine hot section hardware at temperatures to 2100°F.
Certified Material for Critical Service
Hastelloy N is supplied to AMS 5786 (bars, forgings, and tubing). Material is produced by vacuum induction melting (VIM) or VIM plus VAR for maximum cleanliness. Certified mill test reports document composition including molybdenum content, mechanical properties at room and elevated temperatures, and solution anneal condition. Traceability to the specific melt heat is maintained throughout all processing steps.