Incoloy 925丨UNS N09925
Incoloy 925 (Alloy 925 / UNS N09925) is a precipitation-hardened nickel-iron-chromium alloy strengthened with molybdenum, copper, titanium, and aluminum additions. Developed from Incoloy 825, it combines excellent resistance to sulfide stress cracking, chloride stress corrosion cracking, and aggressive oilfield environments with significantly enhanced mechanical strength. Incoloy 925 is widely used in downhole equipment, wellhead components, fasteners, valves, and offshore oil and gas applications. J&A Alloy supplies Incoloy 925 in bar, rod, forging, pipe, tube, and custom-machined forms with full traceability and EN 10204 3.1 certification.
Incoloy 925 Supplier & Manufacturer
Incoloy 925, also known as Alloy 925 or UNS N09925, is a precipitation-hardenable nickel-iron-chromium alloy engineered for high-strength corrosion-resistant applications in the oil and gas industry. Based on the chemistry of Incoloy 825, Alloy 925 incorporates titanium and aluminum additions that enable age hardening while preserving the excellent corrosion resistance of its parent alloy.
The alloy provides outstanding resistance to hydrogen sulfide (H₂S), carbon dioxide (CO₂), chlorides, and sour gas environments. Combined with its high yield strength and excellent fatigue properties, Incoloy 925 is widely selected for critical downhole and subsea components exposed to severe pressure, temperature, and corrosive conditions.
Its compliance with NACE MR0175 / ISO 15156 requirements makes Incoloy 925 a preferred material for offshore drilling, production equipment, and high-reliability oilfield systems.
Features of Incoloy 925
- Excellent resistance to sour gas environments.
- Outstanding resistance to sulfide stress cracking.
- High strength through precipitation hardening.
- Excellent resistance to seawater corrosion.
- Superior resistance to pitting and crevice corrosion.
- Good resistance to chloride stress corrosion cracking.
- Excellent fatigue and mechanical performance.
- Suitable for high-pressure oilfield service.
- NACE MR0175 / ISO 15156 compliant.
- Long service life in offshore environments.
Chemical Composition of Incoloy 925
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 42.0 – 46.0 |
| Iron (Fe) | Balance |
| Chromium (Cr) | 19.5 – 23.5 |
| Molybdenum (Mo) | 2.5 – 3.5 |
| Copper (Cu) | 1.5 – 3.0 |
| Titanium (Ti) | 1.9 – 2.4 |
| Aluminum (Al) | 0.1 – 0.5 |
| Carbon (C) | ≤ 0.03 |
| Manganese (Mn) | ≤ 1.00 |
| Silicon (Si) | ≤ 0.50 |
| Sulfur (S) | ≤ 0.03 |
Physical Properties of Incoloy 925
| Property | Value |
|---|---|
| Density | 8.14 g/cm³ |
| Melting Range | 1343 – 1369°C |
| Electrical Resistivity | 1.13 μΩ·m |
| Thermal Conductivity | 11.1 W/m·K |
| Specific Heat Capacity | 460 J/kg·K |
| Modulus of Elasticity | 196 GPa |
Mechanical Properties of Incoloy 925
Age-Hardened Condition
| Property | Value |
|---|---|
| Tensile Strength | ≥ 930 MPa |
| Yield Strength (0.2% Offset) | ≥ 655 MPa |
| Elongation | ≥ 25% |
| Hardness | ≤ 35 HRC |
Corrosion Resistance
Incoloy 925 offers excellent resistance to a broad range of corrosive media encountered in oil and gas production environments. The alloy performs exceptionally well in sour gas service, resisting sulfide stress cracking, hydrogen embrittlement, and chloride stress corrosion cracking.
The combination of nickel, chromium, molybdenum, and copper provides outstanding resistance to pitting corrosion, crevice corrosion, and reducing acids. In offshore and subsea applications, Incoloy 925 demonstrates superior long-term reliability compared with many conventional stainless steels and high-strength alloys.
High Temperature Performance
| Property | Performance |
|---|---|
| Maximum Recommended Service Temperature | Up to 650°C |
| Oxidation Resistance | Very Good |
| Fatigue Resistance | Excellent |
| Stress Corrosion Resistance | Excellent |
Available Forms
| Product Form | Availability |
|---|---|
| Bar | Round, Flat, Hex |
| Rod | Available |
| Forgings | Available |
| Pipe | Available |
| Tube | Available |
| Flange | Available |
| Fasteners | Available |
| Custom Components | Available |
Applications of Incoloy 925
- Downhole tubing hangers
- Wellhead equipment
- Completion systems
- Oilfield fasteners
- Subsea connectors
- Valve stems and components
- Offshore production systems
- Pump shafts
- Marine engineering hardware
- High-pressure corrosion-resistant components
Incoloy 925 vs Other Alloys
| Property | Incoloy 925 | Incoloy 825 | Inconel 725 | Super Duplex |
|---|---|---|---|---|
| Strength | Excellent | Moderate | Excellent | Good |
| Sour Service Resistance | Excellent | Excellent | Excellent | Good |
| Seawater Resistance | Excellent | Very Good | Excellent | Good |
| Cost Efficiency | Very Good | Excellent | Good | Excellent |
Welding & Fabrication
Incoloy 925 exhibits good weldability using standard nickel alloy welding methods including GTAW, GMAW, and SMAW. Welding is generally carried out in the solution-annealed condition, followed by aging treatment when maximum mechanical properties are required. Proper fabrication procedures help maintain corrosion resistance and mechanical performance.
Standards & Equivalent Grades
| Standard | Designation |
|---|---|
| UNS | N09925 |
| ASTM Forgings | B805 |
| NACE | MR0175 / ISO 15156 |
| Oil & Gas Service | Sour Service Applications |
| Trade Name | Incoloy 925 / Alloy 925 |
Frequently Asked Questions
What is Incoloy 925?
Incoloy 925 is a precipitation-hardened nickel-iron-chromium alloy developed from Incoloy 825, offering higher strength while maintaining excellent corrosion resistance.
What is Incoloy 925 used for?
It is widely used in oil and gas production equipment, downhole tools, wellhead systems, subsea hardware and offshore fasteners.
What is the UNS number of Incoloy 925?
The UNS designation is UNS N09925.
Is Incoloy 925 suitable for sour service?
Yes. Incoloy 925 is designed for sour gas environments and is commonly used in accordance with NACE MR0175 requirements.
What is the difference between Incoloy 925 and Incoloy 825?
Incoloy 925 can be precipitation hardened for significantly higher strength, while Incoloy 825 is primarily used for corrosion resistance without age hardening.
What is the difference between Incoloy 925 and Inconel 725?
Both alloys provide excellent corrosion resistance and high strength, but Inconel 725 generally offers higher nickel content and greater strength for the most demanding subsea applications.
Is Incoloy 925 resistant to seawater?
Yes. The alloy provides excellent resistance to seawater corrosion, pitting and crevice corrosion.
Can Incoloy 925 be welded?
Yes. It can be welded using standard nickel alloy welding processes and subsequently heat treated if required.
Is Incoloy 925 NACE compliant?
Yes. Properly processed Incoloy 925 can meet NACE MR0175 / ISO 15156 requirements.
Which industries use Incoloy 925?
Oil and gas, offshore engineering, marine engineering, petrochemical processing and energy industries commonly use Incoloy 925.
What forms are available for Incoloy 925?
Bar, rod, forging, pipe, tube, flange, fastener, and custom-machined component forms are commonly available.
Why choose Incoloy 925 for offshore applications?
Its combination of high strength, sour service resistance, seawater corrosion resistance, and long-term reliability makes it ideal for critical offshore equipment.
Why Choose J&A Alloy
J&A Alloy specializes in supplying high-performance nickel alloys and corrosion-resistant materials for the oil and gas, offshore, and energy industries.
We provide:
- EN 10204 3.1 Mill Test Certificates
- NACE-compliant material solutions
- Full material traceability
- Custom forging and machining services
- Global logistics support
- Strict quality control procedures
- Fast delivery and technical assistance
With extensive experience in corrosion-resistant alloys and oilfield materials, J&A Alloy is a trusted global supplier of Incoloy 925 products for critical service applications.
