Alloy 925,Incoloy 925,UNS N09925,E FORU

### **Alloy 925 / Incoloy® 925 / UNS N09925** #### **Age-Hardenable Nickel-Iron-Chromium Alloy for Corrosive and High-Strength Service** **Overview** Alloy 925 (commonly known by its trade name **Incoloy® 925**) is a precipitation-hardenable nickel-iron-chromium alloy with additions of molybdenum, copper, and titanium. It was developed to provide high strength and excellent corrosion resistance in severe environments, particularly in sour gas (hydrogen sulfide) and acidic conditions. Its properties are achieved through a solution annealing and aging treatment, which precipitates the gamma prime phase (Ni3(Ti, Al)), significantly increasing its strength. It is a versatile alloy for oil and gas, chemical processing, and marine applications where both mechanical integrity and corrosion resistance are critical. --- ### **Chemical Composition (Weight %)** The typical chemical composition of Alloy 925 is outlined below. | Element | Content (%) | Key Function | | :--- | :--- | :--- | | **Nickel (Ni)** | 42.0 - 46.0 | Base element, provides inherent corrosion resistance and austenitic matrix. | | **Chromium (Cr)** | 19.5 - 22.5 | Confers resistance to oxidizing environments and high-temperature corrosion. | | **Iron (Fe)** | 22.0 min (Balance) | Stabilizes the austenitic structure. | | **Molybdenum (Mo)** | 2.5 - 3.5 | Enhances resistance to pitting and crevice corrosion, and strengthens the matrix. | | **Copper (Cu)** | 1.5 - 3.0 | Provides resistance to reducing acids, particularly sulfuric acid. | | **Titanium (Ti)** | 1.9 - 2.4 | Primary age-hardening element via formation of Ni₃Ti. | | **Aluminum (Al)** | 0.1 - 0.5 | Co-precipitates with Titanium to form the strengthening gamma prime phase (Ni₃(Ti,Al)). | | **Carbon (C)** | 0.03 max | Controlled to prevent sensitization and intergranular corrosion. | | **Manganese (Mn)** | 0.50 max | | Improves hot workability. | | **Silicon (Si)** | 0.50 max | | Deoxidizer during melting. | | **Sulfur (S)** | 0.03 max | | Impurity, controlled to prevent hot shortness. | | **Phosphorus (P)**| 0.03 max | | Impurity, controlled. | --- ### **Physical Properties** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.08 g/cm³ (0.292 lb/in³) | | **Melting Range** | ~ 1335 - 1380 °C (2440 - 2520 °F) | | **Mean Coefficient of Thermal Expansion** | 20 - 300°C (68 - 572°F): **13.7 x 10⁻⁶/°C** (7.6 x 10⁻⁶/°F)
20 - 500°C (68 - 932°F): **14.5 x 10⁻⁶/°C** (8.1 x 10⁻⁶/°F) | | **Thermal Conductivity** | 12.3 W/m·K (85 Btu·in/hr·ft²·°F) at 100°C (212°F) | | **Specific Heat** | 440 J/kg·K (0.105 Btu/lb·°F) at 100°C (212°F) | | **Electrical Resistivity** | 1.12 μΩ·m at 21°C (70°F) | | **Modulus of Elasticity (Young's Modulus)** | 196 GPa (28.4 x 10⁶ psi) at 21°C (70°F) | | **Magnetic Permeability** | Typically < 1.005 (Essentially non-magnetic in annealed condition). | --- ### **Mechanical Properties (Typical for Aged Condition)** | Property | At Room Temperature | At 315°C (600°F) | | :--- | :--- | :--- | | **Tensile Strength** | 1035 MPa (150 ksi) min | 965 MPa (140 ksi) | | **Yield Strength (0.2% Offset)** | 760 MPa (110 ksi) min | 690 MPa (100 ksi) | | **Elongation (in 50 mm / 2 in)** | 20% min | 18% | | **Reduction of Area** | 35% min | 35% | | **Hardness (Rockwell C)** | 28 - 35 HRC | - | *Note: Material is supplied in the solution-annealed condition (soft) for fabrication and is subsequently aged to achieve the high-strength properties listed above.* --- ### **International Standards** Alloy 925 is covered by several international material standards for various product forms: * **ASTM:** * B 805: Standard Specification for Precipitation Hardening Nickel Alloy Bars, Forgings, and Forging Stock. * B 804: Standard Specification for UNS N08925, UNS N08354, and UNS N08926 Welded Tube. * B 423 / B 424: Standard Specification for Seamless and Welded Tube/Pipe (UNS N08825 and N08221), with Alloy 925 often supplied to these specifications by agreement. * **ASME:** SB-805 (Equivalent to ASTM B805 for pressure vessel code use). * **API (American Petroleum Institute):** Recommended for downhole components in Standard 6A and 6ACRA. * **UNS:** N09925 * **EN (European Standard):** 2.4856 (Material Number) --- ### **Product Applications** Alloy 925 is widely used in demanding applications across several industries: 1. **Oil and Gas Industry:** * **Downhole Tools:** Casing, tubing, hangers, packers, and mandrels for sour gas (H₂S) wells. * **Fasteners:** High-strength bolts, nuts, and wellhead components. * **Valve and Pump Components:** For corrosive and high-pressure service. 2. **Chemical Processing:** * **Reactors, Vessels, and Heat Exchangers:** Handling sulfuric and phosphoric acids, and other aggressive chemicals. * **Piping Systems and Fittings:** For processes involving chlorides and acidic environments. 3. **Marine and Offshore:** * **Subsea Systems:** Components for Christmas trees, manifolds, and flowlines. * **Shafts and Propeller Blades:** In highly corrosive seawater applications. 4. **Pollution Control:** * **Flue Gas Desulfurization (FGD) Systems:** Components like fan wheels, dampers, and spacer bars exposed to acidic condensates. --- ### **Key Characteristics & Advantages** * **Excellent Corrosion Resistance:** Outstanding resistance to sour gas (H₂S/Chlorides), pitting, crevice corrosion, and stress corrosion cracking (SCC). * **High Strength:** Achieves high strength and hardness through a simple aging heat treatment. * **Good Fabricability:** Can be welded and fabricated using standard techniques, preferably in the solution-annealed condition. * **Versatility:** Performs well in a wide range of temperatures, from cryogenic to moderately high temperatures (~550°C / 1000°F). **Disclaimer:** *Incoloy® is a registered trademark of Special Metals Corporation, a PCC company. The values provided are typical and for informational purposes only. For critical applications, always consult the official material data sheets from the supplier and relevant design codes.*

Packing of Standard Packing: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 1651 gallon liquid totes Special package is available on request.