Nickel Alloy Hastelloy N-SR (Stress relieved)
Heat-treated state
UNS N10003 · EN 2.4675
Used on cold-formed or welded assemblies to cut residual stress while keeping part of the cold-work strength.
Values for the SR condition
Other Hastelloy N tempers and conditions
Hastelloy N is listed in 7 conditions; see the grade overview at Hastelloy N.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As cast | For salt-pump casings and valve bodies that cannot be wrought; coarse dendritic structure gives lower ductility. | 300 | 550 | 15 | 14 HRC | 1.3 % IACS |
SADefault Solution annealed | Standard supply condition for plate, sheet, tube and forgings in molten-salt and HF service; best corrosion resistance and ductility. | 320 | 790 | 50 | 195 HB | — |
Modified Hastelloy N (Nb and/or Ti added), solution annealed | Choose when tellurium-induced intergranular cracking or neutron-irradiation embrittlement must be resisted in a molten-salt reactor loop. | 350 | 830 | 45 | 205 HB | 1.4 % IACS |
As-welded deposit | Reference condition for weldments and for weld-metal qualification; ductility lower than base metal but no PWHT is required. | 420 | 760 | 33 | 16 HRC | 1.4 % IACS |
SRThis page Stress relieved | Used on cold-formed or welded assemblies to cut residual stress while keeping part of the cold-work strength. | 480 | 860 | 35 | 18 HRC | 1.4 % IACS |
Cold drawn | Bar and rod for machined fittings, pump shafts and fasteners where higher yield and better surface are wanted. | 620 | 900 | 28 | 21 HRC | 1.4 % IACS |
Cold worked | Springy strip and small-bore tubing where high strength matters more than ductility; anneal before molten-salt service. | 800 | 1,030 | 15 | 30 HRC | 1.4 % IACS |
What is Hastelloy N-SR?
Hastelloy N-SR is Hastelloy N heat treated to SR — used on cold-formed or welded assemblies to cut residual stress while keeping part of the cold-work strength. Hastelloy N-SR has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 70% of nickel alloy grades. Elongation at break is 35% and the elastic modulus is 213 GPa (30.9 Msi). Hastelloy N-SR has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 85% of nickel alloy grades. It melts at 1,300°C (2,372 °F). SA is the default condition FabDigit quotes; SR is available on request or by drawing note.
Hastelloy N-SR properties
Typical room-temperature values for Hastelloy N-SR; 23 are specific to this condition. Other listed values are Hastelloy N reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Hastelloy N-SR has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 85% of nickel alloy grades. It melts at 1,300°C (2,372 °F).
Mechanical13
Hastelloy N-SR has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 70% of nickel alloy grades. Elongation at break is 35% and the elastic modulus is 213 GPa (30.9 Msi).
Thermal6
Hastelloy N-SR is rated for continuous service to 704°C (1,299 °F). It conducts heat at 11.6 W/m·K (6.7 BTU/hr·ft·°F), better than 60% of nickel alloy grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
Hastelloy N-SR conducts electricity at 1.4 % IACS, worse than 65% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 74% of nickel alloy grades.
Sustainability4
Producing a kilogram of Hastelloy N-SR takes about 165 MJ of energy and emits 12.5 kg of CO₂ — more than 54% of nickel alloy grades. Typical recycled content is 30%.
Manufacturability8
Hastelloy N-SR's machinability is poor (20/100, better than 53% of nickel alloy grades); weldability very good (80/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Hastelloy N-SR
Is Hastelloy N easy to machine?
Work-hardens fast and is gummy: use rigid setups, positive-rake carbide, low speed (15–25 m/min) with heavy feed, flood coolant and no dwelling.
Can Hastelloy N be welded?
Readily GTAW/GMAW/SMAW welded with matching Hastelloy N filler; keep low heat input and interpass temperature, no preheat or PWHT needed, avoid oxide/sulfur contamination.
Can Hastelloy N be formed, bent or molded?
Cold form in the annealed condition with ~2× the force of stainless; hot work at 1050–1180 °C and re-solution anneal at ~1175 °C followed by rapid cooling.
What surface finishes work on Hastelloy N?
Not anodizable; pickle/grit-blast then passivate or electropolish, and remove all heat tint before molten-salt or HF service.
Hastelloy N chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Mo | 15 – 18 | 16 |
| Cr | 6 – 8 | 7 |
| Fe | ≤ 5 | 3 |
| C | 0.04 – 0.08 | 0.06 |
| Mn | ≤ 1 | 0.5 |
| Si | ≤ 1 | 0.5 |
| W | ≤ 0.5 | — |
| V | ≤ 0.5 | 0.25 |
| Co | ≤ 0.2 | — |
| Cu | ≤ 0.35 | — |
| Al+Ticombined; Nb/Ti intentionally added in modified variants | ≤ 0.5 | — |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| B | ≤ 0.01 | — |
| Nibalance, typically ~70–72 % | balance | — |
Hastelloy N-SR — frequently asked
What is Hastelloy N-SR used for?
Hastelloy N-SR is typically used for molten salt reactor piping and vessels, fluoride salt heat exchangers, nuclear research reactor components and high-temperature molten-salt process equipment. In short: fluoride salt reference alloy; stable to 704 °C; low machinability, weld-friendly.
What is the yield strength of Hastelloy N-SR?
Hastelloy N-SR has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 70% of nickel alloy grades. Strength varies by condition: see the 7 listed tempers.
Is Hastelloy N-SR easy to machine?
Not especially — machinability is rated poor (20/100, better than 53% of nickel alloy grades). Work-hardens fast and is gummy: use rigid setups, positive-rake carbide, low speed (15–25 m/min) with heavy feed, flood coolant and no dwelling.
Can Hastelloy N-SR be welded?
Yes — weldability is rated very good (80/100). Readily GTAW/GMAW/SMAW welded with matching Hastelloy N filler; keep low heat input and interpass temperature, no preheat or PWHT needed, avoid oxide/sulfur contamination.
What surface finishes work on Hastelloy N-SR?
Not anodizable; pickle/grit-blast then passivate or electropolish, and remove all heat tint before molten-salt or HF service.
Can Hastelloy N-SR be formed, bent or molded?
Cold form in the annealed condition with ~2× the force of stainless; hot work at 1050–1180 °C and re-solution anneal at ~1175 °C followed by rapid cooling.
What is the maximum service temperature of Hastelloy N-SR?
Hastelloy N-SR is rated for continuous use to about 704°C (1,299 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Hastelloy N-SA and Hastelloy N-CW?
SA is the default condition — standard supply condition for plate, sheet, tube and forgings in molten-salt and HF service; best corrosion resistance and ductility. CW: springy strip and small-bore tubing where high strength matters more than ductility; anneal before molten-salt service. Yield strength is 320 MPa in SA versus 800 MPa in CW.
Sources
- ASTM B434 — Ni-Mo-Cr-Fe Alloy (UNS N10003) Plate, Sheet and Strip — ASTM (2022)
- ASTM B573 — Ni-Mo-Cr-Fe Alloy Rod — ASTM (2021)
- Hastelloy N alloy technical data — Haynes International (2020)
- ORNL Reports on INOR-8 / Hastelloy N for Molten-Salt Reactors — Oak Ridge National Laboratory (1970)
- ASM Handbook Vol. 2 — Properties of Nickel and Nickel Alloys — ASM International (1990)
- GB/T 15007 / GH3535 — SAC (2017)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.