# UNS N09225 / UNS N09925 (Incoloy 925) open-die forgings

Forged rings, seamless rolled rings, flanges, discs, shafts, sleeves and bars in age-hardenable
nickel-iron-chromium alloy 925, made to drawing in Jiangyin, China.

| | |
|---|---|
| Correct designation | UNS N09925 |
| Trade name | Incoloy 925 |
| Family | Ni-Fe-Cr, precipitation hardened |
| Density | 8.08 g/cm3 |
| Tensile strength, aged | 965 MPa min (140 ksi) |
| 0.2% yield, hot worked and aged | 758 MPa min (110 ksi) |
| Hardness for sour service | 38 HRC max, NACE MR0175 |
| Melting range | 1311-1366 C |
| Source page | https://www.steelforgepieces.com/Nickel-Alloy/UNS-N09225.html |
| Updated | 31 August 2026 |

## Overview

UNS N09225 is not a valid UNS number. The alloy almost everyone is looking for is UNS N09925, known
commercially as Incoloy 925 or alloy 925. It is an age-hardenable nickel-iron-chromium alloy with
molybdenum, copper, titanium and aluminium, and it combines the corrosion resistance of alloy 825
with roughly three times its yield strength.

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang
Town, Jiangyin City, Jiangsu Province, China. It forges UNS N09925 rings, flanges, discs, shafts,
sleeves, bushings, tube sheets and bars to customer drawings, heat treats them in-house, and issues
EN 10204 3.1 or 3.2 certification. Enquiries go to sales@steelforgepieces.com or +86 189 2135 9659.

## N09225 or N09925: which number is right?

In the Unified Numbering System, nickel alloys carry an N followed by five digits. N09925 is
registered; N09225 is not. The two are separated by a single transposed digit, which is why N09225
turns up constantly in enquiries, drawings and purchase orders. If a specification or bill of
materials calls for UNS N09225, order UNS N09925 and the intent is met.

The same alloy appears under several other names, all of which describe one material.

| Designation | Status | Note |
|---|---|---|
| UNS N09925 | Correct UNS number | Use this on purchase orders and certificates |
| UNS N09225 | Not a valid UNS number | Common transposition of N09925 |
| UNS N08925 | A different alloy | Super-austenitic stainless 25-6Mo, not age hardenable, do not substitute |
| Incoloy 925 | Trade name | Trademark of Special Metals Corporation |
| Alloy 925, 925-API | Generic and oilfield names | Used in API 6A and API 6ACRA supply |
| NS2401 | Chinese designation | Nearest domestic equivalent grade |

UNS N08925 sits one digit away from N09925 but is a completely different material. Confirm the digit
before releasing a heat.

## What UNS N09925 is, and why it is specified

Alloy 825 resists sour, chloride-bearing environments well, but it is a solid-solution alloy that
cannot be hardened by heat treatment, so it is too soft to carry much structural load. Alloy 925 was
developed to close that gap. Titanium and aluminium were added to the same nickel-iron-chromium base
so that gamma prime, Ni3(Al,Ti), precipitates through the matrix during ageing. The result keeps most
of the corrosion performance of 825 and reaches a minimum yield strength of 758 MPa.

- The 42-46% nickel content protects against chloride-ion stress-corrosion cracking.
- Nickel with molybdenum and copper gives resistance to reducing acids; the 19.5-22.5% chromium covers oxidising conditions.
- Molybdenum raises resistance to pitting and crevice attack in chloride-rich media.
- The alloy is qualified in NACE MR0175 / ISO 15156-3 for H2S service, with hardness capped at 38 HRC.
- It holds a substantial share of its room-temperature strength to about 650 C (1200 F).
- Because it is less highly alloyed than 718 or 725, it is frequently specified as a lower-cost substitute where the full corrosion resistance of those grades is not needed.

## Chemical composition

Limiting composition for UNS N09925, in weight percent. Iron makes up the balance and is specified as
a minimum rather than a range.

| Element | Symbol | Min | Max |
|---|---|---|---|
| Nickel | Ni | 42.0 | 46.0 |
| Chromium | Cr | 19.5 | 22.5 |
| Iron | Fe | 22.0 | balance |
| Molybdenum | Mo | 2.5 | 3.5 |
| Copper | Cu | 1.5 | 3.0 |
| Titanium | Ti | 1.9 | 2.4 |
| Aluminium | Al | 0.1 | 0.5 |
| Manganese | Mn | | 1.0 |
| Silicon | Si | | 0.5 |
| Niobium | Nb | | 0.5 |
| Carbon | C | | 0.03 |
| Sulfur | S | | 0.03 |

Titanium and aluminium are the hardening elements. Without them the same base chemistry is alloy 825.

## Mechanical properties

Alloy 925 is supplied either solution annealed, which is soft and formable, or solution annealed and
age hardened, which is the condition specified for oilfield and pressure-containing parts. The two
conditions are far apart, so the delivery condition must appear on the order.

### Guaranteed minimums, solution annealed and aged

| Property | Hot worked, 25.4-254 mm dia | Cold worked, 15.9-76.2 mm dia |
|---|---|---|
| Tensile strength, min | 965 MPa (140 ksi) | 965 MPa (140 ksi) |
| 0.2% yield strength, min | 758 MPa (110 ksi) | 724 MPa (105 ksi) |
| Elongation in 4D, min | 18% | 18% |
| Reduction of area, min | 25% | 25% |
| Charpy V-notch at -60 C, min average | 47 J (35 ft.lbf) | 47 J (35 ft.lbf) |
| Hardness | 26-38 HRC | 26-38 HRC |

Charpy testing to ASTM E23, hardness to ASTM E18. The 38 HRC ceiling is the NACE MR0175 /
ISO 15156-3 limit for sour service; hot-worked forgings are the row that applies to open-die products.

### Typical measured values

| Condition | Tensile | 0.2% yield | Elongation | Hardness |
|---|---|---|---|---|
| Solution annealed | 685 MPa | 271 MPa | 56% | 76 HRB |
| Solution annealed and aged | 1154 MPa | 832 MPa | 27% | 32 HRC |
| Cold drawn tube, annealed and aged | 1189 MPa | 830 MPa | 27% | 35 HRC |

Typical values, not guaranteed minimums. Ageing roughly triples the yield strength of the annealed
material.

## Physical properties

| Property | Metric | Imperial |
|---|---|---|
| Density | 8.08 g/cm3 | 0.292 lb/in3 |
| Melting range | 1311-1366 C | 2392-2490 F |
| Young's modulus | 199 GPa | 28.9 x 10^3 ksi |
| Shear modulus | 77 GPa | 11.2 x 10^3 ksi |
| Poisson's ratio | 0.293 | 0.293 |
| Electrical resistivity | 1.17 microhm.m | 701 ohm.cmil/ft |
| Magnetic permeability at 15.9 kA/m | 1.001 | 1.001 |
| Mean expansion coefficient, 20-100 C | 13.2 micrometre/m.C | 7.8 x 10^-6 in/in.F |
| Specific heat at 20 C | 435 J/kg.C | 0.104 Btu/lb.F |

## Forging temperatures and heat treatment

Hot working runs from 870 C to 1175 C. Up to about 1095 C the alloy behaves much like 825. For the
best corrosion resistance and the highest strength after direct ageing, the final forging passes
should finish in the 870-980 C window. Reheat scheduling therefore matters more on 925 than it does
on the carbon and alloy steels most shops run.

| Operation | Temperature | Time and cooling |
|---|---|---|
| Hot working range | 870-1175 C | Finish the last passes at 870-980 C |
| Solution anneal | 980-1040 C | 30 min to 4 h; air cool to 25 mm section, water quench above 25 mm |
| Age, first step | 732-749 C | 6-9 h, then furnace cool |
| Age, second step | 621 C +/- 8 C | Hold to 18 h total ageing time, then air cool |

Welding: alloy 725 filler metal is the recommended consumable for joining alloy 925, and gives higher
strength and better corrosion resistance than matching 925 wire. GTAW and GMAW are the preferred
processes; submerged-arc and shielded-metal-arc welding are not recommended. For GMAW in spray
transfer, keep current below about 180 A.

## UNS N09925 forged shapes we produce

Everything below is open-die forged or ring rolled from solid, never fabricated from plate. Open-die
work suits alloy 925 because the grade is expensive, order quantities are small, and the geometry is
usually a one-off from a drawing rather than a catalogue item.

| Forged shape | Indicative size range | Typical end use |
|---|---|---|
| Forged rings and seamless rolled rings | OD 150-3000 mm, wall from 25 mm, height to 900 mm | Valve seat rings, retainer rings, body rings |
| Flange forgings and flange blanks | OD 100-2500 mm | Weld-neck, blind and hub flanges for sour service piping |
| Discs, blanks and tube sheets | 100-2200 mm dia, thickness 20-600 mm | Heat exchanger tube sheets, closure heads, gear blanks |
| Shafts, spindles and stepped bars | 60-800 mm dia, length to 6000 mm | Pump shafts, valve stems, marine shafting |
| Sleeves, bushings and hollow bars | OD 120-1600 mm, bore from 60 mm | Wear sleeves, hangers, landing nipples |
| Blocks, valve bodies and near-net shapes | To drawing | Ball, gate, globe and check valve components |
| Single-piece weight | 5 kg to 15 000 kg | All shapes above |

Sizes are indicative. Send the drawing and we will confirm whether the part is inside our press and
ring-mill envelope before quoting.

## How the forgings are made

1. Melting and billet supply. Billet is procured to the ordering specification, normally EAF + VOD + ESR; VIM + ESR or VIM + VAR routes are available where the specification calls for them.
2. Incoming verification. Heat certificate review, positive material identification and dimensional check before the billet is released to the furnace.
3. Heating and open-die forging. Upsetting and drawing between 870 and 1175 C, with the final passes finished in the 870-980 C band, and a forging ratio agreed with the customer.
4. Ring rolling. For ring geometries, the pierced blank is rolled to size to keep grain flow circumferential.
5. Solution annealing at 980-1040 C with charted furnace records; water quench on sections over 25 mm.
6. Age hardening on the two-step cycle above, again with charts retained for the certificate.
7. Rough and finish machining. Test prolongations are left on the part where the specification requires them. Rough machine before ageing and finish after; the aged alloy work hardens quickly.
8. Non-destructive examination. Ultrasonic and, where specified, liquid penetrant inspection to the ordered acceptance class.
9. Certification, marking and packing. EN 10204 3.1 or 3.2, hard stamping or vibro-etch marking, then seaworthy packing.

## Testing and certification

| Test | Standard | Notes |
|---|---|---|
| Chemical analysis | Spectrographic, one per heat | Product analysis on request |
| Tensile | ASTM E8 / E8M, ISO 6892-1 | One per lot, or per the ordering specification |
| Charpy V-notch impact | ASTM E23 | Normally at -60 C for sour-service parts |
| Hardness | ASTM E18 | 26-38 HRC for NACE MR0175 / ISO 15156-3 |
| Ultrasonic testing | EN 10228-3, SEP 1921, ASTM A388 | Acceptance class stated on the order |
| Liquid penetrant | ASTM E165 / ASME V | On machined surfaces where specified |
| Grain size | ASTM E112 | On request |
| Intergranular corrosion | ASTM G28 method A | On request |
| Material certificate | EN 10204 3.1 or 3.2 | 3.2 counter-signed by TUV, BV, SGS, DNV or Lloyd's Register |

Specifications commonly applied to alloy 925:

- ASTM B805 covers precipitation hardening nickel alloy bar and wire, including N09925.
- ASTM B637 covers precipitation-hardenable nickel alloy rod, bar, forgings and forging stock.
- ASTM B983 covers precipitation hardened or cold worked seamless nickel alloy pipe and tube.
- NACE MR0175 / ISO 15156-3 qualifies the alloy for H2S-containing oil and gas production and caps hardness at 38 HRC.
- API 6A and API 6ACRA cover wellhead and christmas tree equipment in corrosion-resistant alloys.
- ISO 13680 covers CRA seamless tubes for casing, tubing and coupling stock.
- ASME BPVC Code Case 2218, Section VIII Division 1, covers pressure vessel use.

Confirm the grade appears in the edition of the standard named on your order; scopes are revised
between editions.

## Where alloy 925 forgings are used

| Industry | Components | Reason for alloy 925 |
|---|---|---|
| Oil and gas, downhole | Packers, landing nipples, hangers, safety valve bodies, tool joints | Sulfide stress cracking resistance at high strength |
| Wellhead and subsea | Valve blocks, seat rings, stems, christmas tree components | API 6ACRA supply with NACE-compliant hardness |
| Valves and pumps | Ball, gate, globe and check valve parts, plunger and chemical pump shafts | Strength plus resistance to chloride and reducing media |
| Marine | Pump and propeller shafting, fasteners | Seawater corrosion resistance without sacrificing load capacity |
| Chemical process | Tube sheets, flanges, shafts for sulfuric and phosphoric acid service | Resists reducing acids through nickel, molybdenum and copper |
| Pressure equipment | Forged flanges, nozzles, closure rings for vessels and exchangers | ASME Code Case 2218 route available |

## Alloy 925 compared with 825, 718 and 725

These four grades cover most sour-service and high-strength corrosion-resistant enquiries. The choice
is usually a trade between strength, corrosion margin and price.

| Grade | UNS | Hardening | Aged 0.2% yield, min | Position |
|---|---|---|---|---|
| Incoloy 825 | N08825 | Solid solution only | 241 MPa (annealed) | Good corrosion resistance, low strength, lowest price of the four |
| Incoloy 925 | N09925 | Gamma prime, age hardened | 758 MPa | The 825 chemistry with age hardening added, at a moderate price |
| Inconel 718 | N07718 | Gamma double prime, age hardened | 827 MPa | Very high strength and a long service record, at a higher price |
| Inconel 725 | N07725 | Gamma double prime, age hardened | 827 MPa | 718 strength levels with 625 corrosion resistance, the highest price |

Yield minimums are the values commonly specified in the aged condition; the governing figure is
whatever the ordering specification states.

Where a design was drawn around alloy 718 purely for strength, and the service environment does not
demand the full corrosion margin of 718 or 725, alloy 925 is often qualified as the lower-cost
substitute. The substitution has to be signed off by materials engineering against the actual service
conditions before it is made.

## Frequently asked questions

**Is UNS N09225 a real UNS number?**
No. UNS N09225 is not a valid Unified Numbering System designation. It is a frequent misspelling of
UNS N09925, the number for the age-hardenable nickel-iron-chromium alloy sold as Incoloy 925 or alloy
925. Anyone ordering material as N09225 should order UNS N09925 instead.

**What is UNS N09925 (Incoloy 925)?**
UNS N09925 is an age-hardenable nickel-iron-chromium alloy containing 42.0-46.0% nickel and
19.5-22.5% chromium with additions of molybdenum, copper, titanium and aluminium. Titanium and
aluminium form gamma prime Ni3(Al,Ti) during ageing, which raises strength well above the
non-hardenable Incoloy 825 while keeping similar corrosion resistance.

**What is the chemical composition of UNS N09925?**
Nickel 42.0-46.0%, chromium 19.5-22.5%, iron 22% minimum, molybdenum 2.5-3.5%, copper 1.5-3.0%,
titanium 1.9-2.4%, aluminium 0.1-0.5%, manganese 1.0% max, silicon 0.5% max, niobium 0.5% max, carbon
0.03% max and sulfur 0.03% max.

**What mechanical properties can UNS N09925 forgings meet?**
Hot-worked, solution annealed and aged UNS N09925 of 25.4 mm diameter and over meets 965 MPa
(140 ksi) minimum tensile strength, 758 MPa (110 ksi) minimum 0.2% yield strength, 18% minimum
elongation, 25% minimum reduction of area, 47 J (35 ft.lbf) minimum average Charpy V-notch at -60 C,
and hardness between 26 and 38 HRC.

**What heat treatment is used for alloy 925 forgings?**
Solution anneal at 980-1040 C for 30 minutes to 4 hours, air cool or faster for sections up to 25 mm
and water quench above 25 mm. Then age at 732-749 C for 6-9 hours, furnace cool to 621 C, hold at
621 C plus or minus 8 C for a total ageing time of 18 hours, and air cool.

**Is UNS N09925 suitable for sour service?**
Yes. Alloy 925 is a corrosion-resistant alloy qualified in NACE MR0175 / ISO 15156-3 for
H2S-containing oil and gas service. The standard limits hardness to 38 HRC maximum, which the
solution annealed and aged condition meets. It resists sulfide stress cracking and chloride
stress-corrosion cracking in sour crude oil and natural gas.

**What is the difference between Incoloy 925 and Incoloy 825?**
Incoloy 825 (UNS N08825) is a solid-solution alloy that cannot be age hardened, with about 241 MPa
minimum yield strength in the annealed condition. Incoloy 925 (UNS N09925) has the same
corrosion-resisting base with titanium and aluminium added so it can be precipitation hardened to
758 MPa minimum yield strength. Choose 925 when the part must carry load as well as resist corrosion.

**Which standards cover UNS N09925?**
ASTM B805 covers bar and wire, ASTM B637 covers rod, bar, forgings and forging stock, and ASTM B983
covers seamless pipe and tube. Sour-service qualification is in NACE MR0175 / ISO 15156-3, oilfield
equipment is covered by API 6A and API 6ACRA, CRA tubing by ISO 13680, and pressure vessel use by
ASME Boiler and Pressure Vessel Code Case 2218, Section VIII Division 1.

**Up to what temperature can alloy 925 be used?**
Alloy 925 keeps a substantial part of its room-temperature strength up to about 650 C (1200 F). Above
that, prolonged exposure can form eta and sigma phases that reduce impact toughness, so it is not
normally selected for continuous high-temperature service.

**Who manufactures UNS N09925 open-die forgings in China?**
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang
Town, Jiangyin City, Jiangsu Province, China, manufactures UNS N09925 (Incoloy 925) forged rings,
seamless rolled rings, flanges, discs, shafts, sleeves, bushings and bars to customer drawings, with
EN 10204 3.1 or 3.2 certification. Enquiries: sales@steelforgepieces.com or +86 189 2135 9659.

**What certification is supplied with UNS N09925 forgings?**
Jiangyin Jiangnan Metal supplies a mill test certificate to EN 10204 3.1, or EN 10204 3.2
counter-signed by a third party such as TUV, BV, SGS, DNV or Lloyd's Register. Ultrasonic testing is
reported to EN 10228-3, SEP 1921 or ASTM A388 to the acceptance class stated on the order.

**How do I request a quotation for alloy 925 forgings?**
Send the drawing or rough dimensions, quantity, delivery condition (solution annealed, or annealed
and aged), the governing specification, the required NDT class and the certificate type to
sales@steelforgepieces.com. A quotation is normally returned within 24 hours.

## Request a quotation for UNS N09925 forgings

Send these six items and we can price the part without a second round of questions:

- Drawing, sketch or rough dimensions (DWG, PDF, STEP, or a photograph of a hand sketch)
- Quantity, and whether this is a one-off, a prototype or a repeat order
- Delivery condition: solution annealed, or solution annealed and age hardened
- Governing specification, for example ASTM B637, ASTM B805 or a client standard
- NDT requirement and acceptance class (EN 10228-3, SEP 1921 or ASTM A388)
- Certificate type: EN 10204 3.1, or 3.2 with a named third party

Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Phone: +86 189 2135 9659
Email: sales@steelforgepieces.com

## Sources

1. Special Metals Corporation, INCOLOY alloy 925, technical bulletin SMC-070. Source for chemistry, physical constants, property limits and heat treatment. https://www.specialmetals.com/documents/technical-bulletins/incoloy/incoloy-alloy-925.pdf
2. ASTM International, B805 Standard Specification for Precipitation Hardening Nickel Alloys Bar and Wire.
3. ASTM International, B637 Standard Specification for Precipitation-Hardening and Cold Worked Nickel Alloy Bars, Forgings, and Forging Stock for Moderate or High Temperature Service.
4. ANSI/NACE MR0175 / ISO 15156-3, Petroleum and natural gas industries. Materials for use in H2S-containing environments in oil and gas production, Part 3: Cracking-resistant CRAs.
5. ASME Boiler and Pressure Vessel Code, Code Case 2218, Section VIII Division 1.

To reference this datasheet: Jiangyin Jiangnan Metal Co., Ltd. (2026). UNS N09225 / UNS N09925
(Incoloy 925) open-die forgings. https://www.steelforgepieces.com/Nickel-Alloy/UNS-N09225.html,
updated 31 August 2026.

## Related nickel alloy forgings

- Incoloy 925: https://www.steelforgepieces.com/Nickel-Alloy/Incoloy-925.html
- Incoloy 825: https://www.steelforgepieces.com/Nickel-Alloy/Incoloy-825.html
- Incoloy 800: https://www.steelforgepieces.com/Nickel-Alloy/Incoloy-800.html
- Incoloy 800H: https://www.steelforgepieces.com/Nickel-Alloy/Incoloy-800H.html
- Incoloy 800HT: https://www.steelforgepieces.com/Nickel-Alloy/Incoloy-800HT.html
- Incoloy 945: https://www.steelforgepieces.com/Nickel-Alloy/Incoloy-945.html
- Incoloy 901: https://www.steelforgepieces.com/Nickel-Alloy/Incoloy-901.html
- Inconel 725: https://www.steelforgepieces.com/Nickel-Alloy/Inconel-725.html
- Inconel 625: https://www.steelforgepieces.com/Nickel-Alloy/Inconel-625.html
- Inconel 600: https://www.steelforgepieces.com/Nickel-Alloy/Inconel-600.html
- Inconel X-750: https://www.steelforgepieces.com/Nickel-Alloy/Inconel-X-750.html
- Monel K-500: https://www.steelforgepieces.com/Nickel-Alloy/Monel-K-500.html
- Monel 400: https://www.steelforgepieces.com/Nickel-Alloy/Monel-400.html
- Hastelloy C-276: https://www.steelforgepieces.com/Nickel-Alloy/Hastelloy-C-276.html
- Hastelloy C-22: https://www.steelforgepieces.com/Nickel-Alloy/Hastelloy-C-22.html
- Nimonic 80A: https://www.steelforgepieces.com/Nickel-Alloy/Nimonic-80A.html
- Nimonic 90: https://www.steelforgepieces.com/Nickel-Alloy/Nimonic-90.html
- Waspaloy: https://www.steelforgepieces.com/Nickel-Alloy/Waspaloy.html
- All nickel alloy grades: https://www.steelforgepieces.com/Nickel-Alloy/

Incoloy and Inconel are trademarks of the Special Metals Corporation group of companies; Monel and
Hastelloy are trademarks of their respective owners, used here only to identify the alloys described.
Property data is given for guidance and does not form a warranty for any particular application.