Nickel Alloy Alloy 825-STA (Solution treated and aged)
Heat-treated state
UNS N08825 · ASTM B424 · EN 2.4858 · BS NA16 · also Incoloy 825
Choose when maximum resistance to intergranular attack after welding or service near sensitizing temperatures is required.
Values for the STA 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 |
|---|---|---|---|---|---|---|
STAThis page 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 | — |
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-STA?
Alloy 825-STA is Alloy 825 heat treated to STA — choose when maximum resistance to intergranular attack after welding or service near sensitizing temperatures is required. Alloy 825-STA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 670 MPa (97.2 ksi) — weaker than 78% of nickel alloy grades. Elongation at break is 44% and the elastic modulus is 196 GPa (28.4 Msi). Alloy 825-STA 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; STA is available on request or by drawing note.
Advantages
- Low embodied carbon — 8.5 kg CO₂/kg, better than 92% of nickel alloy grades
- Forms and bends easily — 78/100, better than 87% of nickel alloy grades
- Readily welded — 85/100, better than 83% of nickel alloy grades
Limitations
- Low strength — 300 MPa (43.5 ksi), worse than 78% of nickel alloy grades
- Limited service temperature — 540°C (1,004 °F), worse than 75% of nickel alloy grades
Alloy 825-STA properties
Typical room-temperature values for Alloy 825-STA; 21 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-STA 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-STA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 670 MPa (97.2 ksi) — weaker than 78% of nickel alloy grades. Elongation at break is 44% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
Alloy 825-STA 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-STA conducts electricity at 1.5 % IACS, better than 59% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 74% of nickel alloy grades.
Sustainability4
Producing a kilogram of Alloy 825-STA 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-STA's machinability is poor (25/100, better than 76% of nickel alloy grades); weldability excellent (85/100); formability very good (78/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Alloy 825-STA
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-STA — frequently asked
What is Alloy 825-STA used for?
Alloy 825-STA 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-STA?
Alloy 825-STA has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 670 MPa (97.2 ksi) — weaker than 78% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Alloy 825-STA easy to machine?
Not especially — machinability is rated poor (25/100, better than 76% 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-STA 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-STA?
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-STA 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-STA?
Alloy 825-STA 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.