Alloy 263,Nimonic 263,UNS N07263,E FORU

### **Alloy 263 / Nimonic® 263 / UNS N07263** **Precipitation-Hardenable Nickel-Cobalt-Chromium Superalloy for Advanced Gas Turbine Applications** #### **1. Overview** **Alloy 263**, commercially known as **Nimonic® 263**, is a precipitation-hardenable nickel-cobalt-chromium superalloy specifically developed for high-temperature applications requiring an optimal combination of creep strength, fabricability, and thermal stability. This alloy exhibits excellent formability and weldability compared to many other precipitation-hardening superalloys, making it particularly suitable for sheet metal components in gas turbine engines. Nimonic 263 maintains good mechanical properties up to 850°C (1562°F) and offers superior resistance to thermal fatigue. #### **2. Chemical Composition (Weight %)** The typical chemical composition of Nimonic 263 is outlined below. The balance is Nickel (Ni). | Element | Content (%) | Key Function | | :--- | :--- | :--- | | **Nickel (Ni)** | Balance | Forms the austenitic matrix and provides fundamental high-temperature strength. | | **Chromium (Cr)** | 19.0 - 21.0 | Provides oxidation and hot corrosion resistance. | | **Cobalt (Co)** | 19.0 - 21.0 | Enhances solid-solution strengthening and elevates γ' solvus temperature. | | **Molybdenum (Mo)** | 5.6 - 6.1 | Provides solid-solution strengthening and enhances creep strength. | | **Titanium (Ti)** | 1.9 - 2.4 | Primary precipitation hardening element forming γ' phase (Ni₃Ti). | | **Aluminum (Al)** | 0.3 - 0.6 | Co-precipitates with titanium to form γ' phase (Ni₃(Al,Ti)). | | **Carbon (C)** | 0.04 - 0.08 | Forms carbides for grain boundary strengthening. | | **Boron (B)** | 0.005 max | Enhances creep strength and grain boundary cohesion. | | **Copper (Cu)** | 0.20 max | Controlled impurity. | | **Iron (Fe)** | 0.70 max | Controlled impurity; kept low to maintain high-temperature properties. | | **Manganese (Mn)** | 0.60 max | Improves hot workability. | | **Silicon (Si)** | 0.40 max | Enhances oxidation resistance. | | **Sulfur (S)** | 0.007 max | Impurity, kept very low to prevent hot shortness. | #### **3. Physical Properties** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.36 g/cm³ (0.302 lb/in³) | | **Melting Range** | ~ 1330 - 1380 °C (2426 - 2516 °F) | | **Mean Coefficient of Thermal Expansion** | 20 - 500°C (68 - 932°F): **14.4 x 10⁻⁶/°C** (8.0 x 10⁻⁶/°F)
20 - 800°C (68 - 1472°F): **15.8 x 10⁻⁶/°C** (8.8 x 10⁻⁶/°F) | | **Thermal Conductivity** | 17.2 W/m·K (119 Btu·in/hr·ft²·°F) at 20°C (68°F)
26.0 W/m·K (180 Btu·in/hr·ft²·°F) at 800°C (1472°F) | | **Specific Heat** | 440 J/kg·K (0.105 Btu/lb·°F) at 20°C (68°F) | | **Electrical Resistivity** | 1.20 μΩ·m at 20°C (68°F) | | **Modulus of Elasticity (Young's Modulus)** | 220 GPa (31.9 x 10⁶ psi) at 20°C (68°F) | | **Magnetic Permeability** | Essentially non-magnetic. | #### **4. Mechanical Properties (Typical for Aged Condition)** | Property | At Room Temperature | At 750°C (1382°F) | At 850°C (1562°F) | | :--- | :--- | :--- | :--- | | **Tensile Strength** | 950 - 1150 MPa (138 - 167 ksi) | ~580 MPa (84 ksi) | ~380 MPa (55 ksi) | | **Yield Strength (0.2% Offset)** | 550 - 750 MPa (80 - 109 ksi) | ~480 MPa (70 ksi) | ~320 MPa (46 ksi) | | **Elongation (in 50 mm / 2 in)** | 25% - 35% | 20% - 30% | 25% - 40% | | **Hardness (Rockwell C)** | 25 - 32 HRC | - | - | #### **5. International Standards** Nimonic 263 is covered by several international and industry-specific standards: * **ASTM:** * **B 637:** Standard Specification for Precipitation-Hardening Nickel Alloy Bars, Forgings, and Forging Stock for High-Temperature Service * **AMS:** * **AMS 5872:** Sheet, Strip, and Plate * **AMS 5706:** Bar and Forging Stock * **BS / EN:** * **BS HR 5012:** Aerospace series * **EN 10095:** Heat resisting steels and nickel alloys * **UNS:** N07263 * **DIN:** 2.4650 (Material Number) * **ISO:** ISO 9723, ISO 9724 * **AECMA:** PR EN 2631 #### **6. Product Applications** Nimonic 263 is widely used in advanced gas turbine applications requiring both high strength and good fabricability: * **Aerospace & Gas Turbines:** * Combustion chamber liners and casings * Afterburner components * Turbine seals and shrouds * Exhaust system components * **Industrial Gas Turbines:** * Transition ducts * Combustion cans * Hot gas path components * **Power Generation:** * Gas turbine components * High-temperature fasteners * **Automotive & Marine:** * High-performance turbocharger components * Exhaust valves and components #### **7. Key Characteristics & Advantages** * **Excellent Fabricability:** Superior formability and weldability compared to many precipitation-hardening superalloys * **Good Creep Strength:** Maintains strength under sustained loading at temperatures up to 850°C (1562°F) * **Superior Thermal Fatigue Resistance:** Excellent resistance to thermal cycling and thermal shock * **Optimized Microstructure:** Balanced γ' formation for optimal strength and stability * **Good Oxidation Resistance:** Adequate corrosion resistance for most gas turbine environments * **Stable Mechanical Properties:** Maintains properties during long-term exposure at high temperatures * **Versatile Application Range:** Suitable for both rotating and static components in high-temperature service --- **Disclaimer:** *Nimonic® is a registered trademark of Rolls-Royce plc. 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 1659 gallon liquid totes Special package is available on request.