Incoloy 925 · UNS N09925
Incoloy 925 (N09925): composition, properties, fittings and flanges
Incoloy 925 (N09925) is Age-hardenable nickel-iron-chromium-molybdenum-copper alloy. Incoloy 925 is specified at Nickel 42.0 - 46.0, Chromium 19.5 - 23.5, Molybdenum 2.50 - 3.50. Incoloy 925 takes Incoloy 825 chemistry and adds titanium and aluminium for ageing, roughly tripling the yield strength so that sour gas wellhead and…
- UNS
- N09925
- W. Nr.
- -
- Density
- 8.08 g/cm³ (0.292 lb/in³)
- Key strength
- 965 MPa / 140 ksi
Identification and standards
| Short form | Incoloy 925 · UNS N09925 |
|---|---|
| Classification | Age-hardenable nickel-iron-chromium-molybdenum-copper alloy |
| UNS | N09925 |
| Werkstoff number | - |
| Material family | Incoloy Alloys |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Nickel (Ni) | 42.0 - 46.0 | Matrix and chloride SCC resistance |
| Chromium (Cr) | 19.5 - 23.5 | Oxidation and pitting resistance |
| Iron (Fe) | 22.0 min | Matrix |
| Molybdenum (Mo) | 2.50 - 3.50 | Pitting and crevice resistance |
| Copper (Cu) | 1.50 - 3.00 | Reducing acid resistance |
| Titanium (Ti) | 1.90 - 2.40 | Gamma-prime hardening |
| Aluminium (Al) | 0.10 - 0.50 | Gamma-prime hardening |
| Carbon (C) | 0.03 max | - |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, min (aged) | 965 MPa / 140 ksi |
|---|---|
| 0.2 % yield strength, min | 758 MPa / 110 ksi |
| Elongation in 2 in, min | 18 % |
| Typical hardness, aged | 28 - 36 HRC |
| NACE status | MR0175 / ISO 15156 listed for sour service |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 8.08 g/cm³ (0.292 lb/in³) |
|---|---|
| Melting range | 1311 - 1366 °C (2390 - 2490 °F) |
| Modulus of elasticity | 199 GPa (28.9 x 10⁶ psi) |
| Thermal conductivity at 20 °C | 12.3 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 13.5 µm/m·°C |
| Specific heat capacity | 435 J/kg·K |
Specifications by product form
| Forgings & flanges | ASTM B637 / NACE MR0175 (UNS N09925) |
|---|---|
| Butt weld fittings | ASTM B366 (WP grade to order) |
| Seamless pipe & tube | ASTM B423 / B705 or to order |
| Plate / sheet / strip | ASTM B424 |
| Bar / rod | ASTM B637 |
| Welding consumables | ERNiCrMo-3; re-age after welding |
| UNS / EN / China | UNS N09925 · NACE MR0175 / ISO 15156 |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Forged flanges blanks and finished flanges to ASME B16.5, B16.47 Series A/B and B16.36
- Butt weld elbows, tees, reducers, caps and stub ends to ASME B16.9 and MSS SP-43
- Seamless pipe and tube to the applicable ASTM / ASME pipe specification
- Forged rings, discs and hubs machined to your drawing
Typical applications
- Sour gas wellhead components, valve bodies and stems
- Downhole tubulars and completion hardware
- High-strength piping in produced water service
- Subsea and surface safety valve components
Welding, forming and machining
- Welding
- Weld in the annealed condition with ERNiCrMo-3 filler, then apply the full ageing cycle to the finished component to recover strength.
- Heat treatment
- Solution anneal at 980 - 1040 °C, then age at 700 - 730 °C for 6 to 8 hours, furnace cool to 620 °C, hold 8 hours and air cool.
- Hot and cold forming
- Hot work in the range stated by the mill for this grade, then re-solution or re-age before final machining so that the delivered condition matches the certificate.
- Machining
- Machine with sharp carbide or high-speed steel tooling, positive rake, constant feed and ample coolant. Never dwell - the surface work-hardens quickly.
Buy Incoloy 925 from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.