Nickel Alloy Alloy 825-HF (Hot Finished)
Grade
UNS N08825 · ASTM B424 · EN 2.4858 · BS NA16 · also Incoloy 825
Economical condition for large-diameter bar, flanges and forgings where surface finish and tight tolerance are not critical.
Values for the HF condition
Other Alloy 825 tempers and conditions
Alloy 825 is listed in 5 conditions; see the grade overview at Alloy 825.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution treated and aged | Choose when maximum resistance to intergranular attack after welding or service near sensitizing temperatures is required. | 300 | 670 | 44 | 158 HB | 1.5 % IACS |
ANNDefault Annealed | Standard stocked condition for plate, sheet, tube and bar; maximum ductility and corrosion resistance. | 310 | 690 | 45 | 150 HB | — |
HFThis page Hot Finished | Economical condition for large-diameter bar, flanges and forgings where surface finish and tight tolerance are not critical. | 310 | 655 | 42 | 165 HB | — |
Cold drawn | Pick for higher strength, straightness and good surface on small-diameter bar, fasteners and instrumentation tubing. | 560 | 790 | 25 | 20 HRC | — |
Cold Worked Hard | Use where maximum strength and spring temper are needed and forming/welding is complete. | 760 | 950 | 12 | 28 HRC | 1.5 % IACS |
What is Alloy 825-HF?
Alloy 825-HF is Alloy 825 in the HF grade — economical condition for large-diameter bar, flanges and forgings where surface finish and tight tolerance are not critical. Alloy 825-HF has a yield strength of 310 MPa (45 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 74% of nickel alloy grades. Elongation at break is 42% and the elastic modulus is 196 GPa (28.4 Msi). Alloy 825-HF has a density of 8.14 g/cm³ (0.294 lb/in³), lighter than 74% of nickel alloy grades. It melts at 1,370°C (2,498 °F). ANN is the default condition FabDigit quotes; HF is available on request or by drawing note.
Advantages
- Low embodied carbon — 8.5 kg CO₂/kg, better than 92% of nickel alloy grades
- Readily welded — 85/100, better than 83% of nickel alloy grades
- Forms and bends easily — 72/100, better than 77% of nickel alloy grades
Limitations
- Limited service temperature — 540°C (1,004 °F), worse than 75% of nickel alloy grades
Alloy 825-HF properties
Typical room-temperature values for Alloy 825-HF; 11 are specific to this condition. Other listed values are Alloy 825 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Alloy 825-HF has a density of 8.14 g/cm³ (0.294 lb/in³), lighter than 74% of nickel alloy grades. It melts at 1,370°C (2,498 °F).
Mechanical14
Alloy 825-HF has a yield strength of 310 MPa (45 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 74% of nickel alloy grades. Elongation at break is 42% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
Alloy 825-HF is rated for continuous service to 540°C (1,004 °F). It conducts heat at 11.1 W/m·K (6.41 BTU/hr·ft·°F), worse than 54% of nickel alloy grades. Thermal expansion is 14 µm/m·K (7.78 µin/in·°F).
Electrical3
Alloy 825-HF conducts electricity at 1.5 % IACS, better than 59% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (82/100), better than 67% of nickel alloy grades.
Sustainability4
Producing a kilogram of Alloy 825-HF takes about 115 MJ of energy and emits 8.5 kg of CO₂ — less than 91% of nickel alloy grades. Typical recycled content is 45%.
Manufacturability8
Alloy 825-HF's machinability is poor (22/100, better than 64% of nickel alloy grades); weldability excellent (85/100); formability very good (72/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Alloy 825-HF
Is Alloy 825 easy to machine?
Work-hardens rapidly — use rigid setups, positive-rake carbide, heavy constant feed, low-to-moderate speed (20–35 m/min carbide) and copious sulfur-free coolant; never dwell in the cut.
Can Alloy 825 be welded?
Readily welded by GTAW/GMAW/SMAW with matching ERNiFeCr-1 (FM 65) or ENiCrMo-3 filler; keep heat input and interpass temperature low, no preheat, no post-weld heat treatment normally required thanks to Ti stabilization.
Can Alloy 825 be formed, bent or molded?
Excellent cold formability (deep drawing, spinning, tube bending) with ~40 % higher forming loads than 304; hot work 870–1180 °C and anneal at 940–1010 °C with rapid cool after heavy cold work.
What surface finishes work on Alloy 825?
Descale by grit blast plus HNO₃-HF pickling; passivate or electropolish for process-fluid cleanliness — anodizing is not applicable, and iron contamination from tooling must be removed to preserve pitting resistance.
Alloy 825 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 |
|---|---|---|
| Niplus Co in some specs | 38 – 46 | 42 |
| Cr | 19.5 – 23.5 | 21.5 |
| Mo | 2.5 – 3.5 | 3 |
| Cuaids sulfuric acid resistance | 1.5 – 3 | 2.2 |
| Tistabilizes against intergranular attack | 0.6 – 1.2 | 0.9 |
| C | ≤ 0.05 | 0.02 |
| Mn | ≤ 1 | 0.5 |
| Si | ≤ 0.5 | 0.25 |
| Al | ≤ 0.2 | 0.1 |
| S | ≤ 0.03 | 0 |
| Febalance, 22 % minimum per ASTM B424 | ≥ 22 (balance) | — |
Alloy 825-HF — frequently asked
What is Alloy 825-HF used for?
Alloy 825-HF is typically used for acid production equipment, pickling tanks, oil/gas tubulars and pollution-control scrubbers. In short: acid-resistant Ni-Fe-Cr workhorse; strong chloride SCC resistance; weldable without PWHT.
What is the yield strength of Alloy 825-HF?
Alloy 825-HF has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 74% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Alloy 825-HF easy to machine?
Not especially — machinability is rated poor (22/100, better than 64% of nickel alloy grades). Work-hardens rapidly — use rigid setups, positive-rake carbide, heavy constant feed, low-to-moderate speed (20–35 m/min carbide) and copious sulfur-free coolant; never dwell in the cut.
Can Alloy 825-HF be welded?
Yes — weldability is rated excellent (85/100). Readily welded by GTAW/GMAW/SMAW with matching ERNiFeCr-1 (FM 65) or ENiCrMo-3 filler; keep heat input and interpass temperature low, no preheat, no post-weld heat treatment normally required thanks to Ti stabilization.
What surface finishes work on Alloy 825-HF?
Descale by grit blast plus HNO₃-HF pickling; passivate or electropolish for process-fluid cleanliness — anodizing is not applicable, and iron contamination from tooling must be removed to preserve pitting resistance.
Can Alloy 825-HF be formed, bent or molded?
Excellent cold formability (deep drawing, spinning, tube bending) with ~40 % higher forming loads than 304; hot work 870–1180 °C and anneal at 940–1010 °C with rapid cool after heavy cold work.
What is the maximum service temperature of Alloy 825-HF?
Alloy 825-HF is rated for continuous use to about 540°C (1,004 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Alloy 825-ANN and Alloy 825 CW-H?
ANN is the default condition — standard stocked condition for plate, sheet, tube and bar; maximum ductility and corrosion resistance. CW-H: use where maximum strength and spring temper are needed and forming/welding is complete. Yield strength is 310 MPa in ANN versus 760 MPa in CW-H.
Sources
- ASTM B424 — Ni-Fe-Cr-Mo-Cu Alloy Plate, Sheet and Strip (UNS N08825) — ASTM International (2023)
- ASTM B425 — Ni-Fe-Cr-Mo-Cu Alloy Rod and Bar — ASTM International (2023)
- ASTM B163 / B423 — Seamless Tube and Pipe, UNS N08825 — ASTM International (2023)
- INCOLOY alloy 825 Technical Bulletin — Special Metals Corporation (2004)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys, Ni-Fe-Cr alloys — ASM International (1990)
- GB/T 15007 / NS1402 — 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.