Nickel Alloy Alloy 890
UNS N08890 · also Incoloy 890
Alloy 890 (N08890, A494 CN-7MS) is a high-nickel cast Ni-Cr-Mo alloy developed for severe sulfuric acid and chloride service, with higher strength and corrosion resistance than standard CN-7M castings.
Reference datasheet — Alloy 890 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the SA condition
Alloy 890 tempers and conditions
Alloy 890 is supplied in 4 conditions, soft to hard. SA is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed and quenched | Standard ASTM A494 delivery condition: heat ≈1120 °C and water quench to dissolve carbides/silicides for full corrosion resistance and ductility. | 200 | 455 | 40 | 160 HB | — |
Weld repaired and re-solution annealed | Foundry-repaired castings that receive a full re-solution treatment after welding; use where minor upgrading is permitted by the purchase spec. | 200 | 445 | 35 | 165 HB | 1.7 % IACS |
hot isostatically pressed then solution annealed | Choose for pressure-boundary or high-integrity pump/valve castings where shrinkage porosity must be closed to raise ductility, fatigue life and NDT acceptance. | 205 | 475 | 45 | 160 HB | 1.7 % IACS |
As fabricated | Only for non-corrosive, dimensionally stable duty or as an intermediate state before machining and solution annealing; grain-boundary phases cut ductility and acid resistance. | 215 | 420 | 20 | 9 HRC | 1.6 % IACS |
What is Alloy 890?
Alloy 890 (N08890, A494 CN-7MS) is a high-nickel cast Ni-Cr-Mo alloy developed for severe sulfuric acid and chloride service, with higher strength and corrosion resistance than standard CN-7M castings. It is chosen for pump and valve hardware in sand or investment castings, typically solution-annealed at 200 MPa yield, 455 MPa tensile, 40 % elongation and ~160 HB. Limits are a 480 °C service ceiling, poor machinability (score 30) and modest weldability (score 45) with hot cracking as the main repair risk; standard CN-7M / Alloy 20 castings are the cheaper alternative where acid duty is less severe. Alloy 890 has a density of 7.95 g/cm³ (0.287 lb/in³), lighter than 86% of nickel alloy grades. It melts at 1,345°C (2,453 °F). Alloy 890 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 455 MPa (66 ksi) — weaker than 95% of nickel alloy grades. Elongation at break is 40% and the elastic modulus is 193 GPa (28 Msi).
What is Alloy 890 used for?
- sulfuric acid pumps
- valve bodies
- process equipment castings
Advantages
- Low embodied carbon — 7 kg CO₂/kg, better than 98% of nickel alloy grades
- Easy to machine — 30/100, better than 90% of nickel alloy grades
- High electrical conductivity — 1.7 % IACS, better than 76% of nickel alloy grades
Limitations
- Low strength — 200 MPa (29 ksi), worse than 95% of nickel alloy grades
- Limited service temperature — 480°C (896 °F), worse than 82% of nickel alloy grades
- Limited formability — 20/100, worse than 75% of nickel alloy grades
Alloy 890 properties
Typical room-temperature values for Alloy 890-SA; bars are the position among nickel alloy grades.
Physical3
Alloy 890 has a density of 7.95 g/cm³ (0.287 lb/in³), lighter than 86% of nickel alloy grades. It melts at 1,345°C (2,453 °F).
Mechanical13
Alloy 890 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 455 MPa (66 ksi) — weaker than 95% of nickel alloy grades. Elongation at break is 40% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
Alloy 890 is rated for continuous service to 480°C (896 °F). It conducts heat at 12 W/m·K (6.93 BTU/hr·ft·°F), better than 65% of nickel alloy grades. Thermal expansion is 15.3 µm/m·K (8.5 µin/in·°F).
Electrical3
Alloy 890 conducts electricity at 1.7 % IACS, better than 76% 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 890 takes about 95 MJ of energy and emits 7 kg of CO₂ — less than 97% of nickel alloy grades. Typical recycled content is 50%.
Manufacturability8
Alloy 890's machinability is poor (30/100, better than 90% of nickel alloy grades); weldability fair (45/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the nickel alloy family
Yield strength against density for every nickel alloy grade FabDigit runs. Alloy 890 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Alloy 890
Is Alloy 890 easy to machine?
Machine like Alloy 20 castings: rigid setup, sharp positive-rake carbide, 20–35 m/min, heavy feeds and flood coolant to beat work hardening and abrasive silicides.
Can Alloy 890 be welded?
GTAW/SMAW with matching high-Si or Alloy 20Cb-3 type filler, low heat input and no preheat; hot cracking is the main risk, and full re-solution anneal restores corrosion resistance.
Can Alloy 890 be formed, bent or molded?
Supplied as sand or investment castings only — provide generous fillets and directional solidification; HIP is recommended for pressure-containing parts.
Alloy 890 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 |
|---|---|---|
| C | ≤ 0.07 | 0.05 |
| Mn | ≤ 1.2 | 0.8 |
| Sihigh Si is the key sulfuric-acid addition | 2.5 – 3.5 | 3 |
| P | ≤ 0.04 | |
| S | ≤ 0.03 | |
| Cr | 18 – 20 | 19 |
| Ni | 22 – 25 | 23.5 |
| Mo | 2.5 – 3 | 2.75 |
| Cu | 1.5 – 2 | 1.75 |
| Febalance, roughly 48–52 % | balance |
What surface finishes work on Alloy 890?
Grind, pickle and passivate in nitric/HF or nitric acid after heat treatment to remove scale; no anodizing, electropolishing gives the best acid-service surface.
Surface treatments FabDigit runs on nickel alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Nickel Alloy Alloy 890 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N08890
- Trade names
- Incoloy 890
- Similar grades
- A494 CN-7MS
How much does Alloy 890 cost?
Alloy 890 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Alloy 890 — frequently asked
What is Alloy 890 used for?
Alloy 890 is typically used for sulfuric acid pumps, valve bodies and process equipment castings. In short: cast Alloy 20 upgrade; sulfuric acid pump grade; castings only, limited weldability.
What is the yield strength of Alloy 890?
Alloy 890 has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 455 MPa (66 ksi) — weaker than 95% of nickel alloy grades. Strength varies by condition: see the 4 listed tempers.
Is Alloy 890 easy to machine?
Not especially — machinability is rated poor (30/100, better than 90% of nickel alloy grades). Machine like Alloy 20 castings: rigid setup, sharp positive-rake carbide, 20–35 m/min, heavy feeds and flood coolant to beat work hardening and abrasive silicides.
Can Alloy 890 be welded?
With care — weldability is rated fair (45/100). GTAW/SMAW with matching high-Si or Alloy 20Cb-3 type filler, low heat input and no preheat; hot cracking is the main risk, and full re-solution anneal restores corrosion resistance.
What surface finishes work on Alloy 890?
Grind, pickle and passivate in nitric/HF or nitric acid after heat treatment to remove scale; no anodizing, electropolishing gives the best acid-service surface.
Can Alloy 890 be formed, bent or molded?
Supplied as sand or investment castings only — provide generous fillets and directional solidification; HIP is recommended for pressure-containing parts.
What is the maximum service temperature of Alloy 890?
Alloy 890 is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Alloy 890-SA and Alloy 890-F?
SA is the default condition — standard ASTM A494 delivery condition: heat ≈1120 °C and water quench to dissolve carbides/silicides for full corrosion resistance and ductility. F: only for non-corrosive, dimensionally stable duty or as an intermediate state before machining and solution annealing; grain-boundary phases cut ductility and acid resistance. Yield strength is 200 MPa in SA versus 215 MPa in F.
How much does Alloy 890 cost?
Alloy 890 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A494/A494M — Castings, Nickel and Nickel Alloy (grade CN-7MS) — ASTM International (2023)
- ASTM A744/A744M — Castings, Iron-Chromium-Nickel, Corrosion Resistant, for Severe Service — ASTM International (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (corrosion-resistant castings) — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials (sulfuric acid service) — ASM International (2005)
- Corrosion-resistant pump and valve casting alloy datasheets (CN-7M / CN-7MS class) — Specialty alloy foundries (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.