Alloy 825,Incoloy 825 Tube,UNS N08825,E FORU

British Specs:BS 3072 BS 3073 BS 3074 BS 3075 BS 3076 NA16，American Specs:ASTM B425 ASTM B424 ASTM B163 (Tube *)，German Specs:WS 2.4858

### **Technical Datasheet: Alloy 825 / Incoloy 825 Tube / UNS N08825** --- #### **1. Overview** **Alloy 825** (commercially known as **Incoloy® 825**) is a nickel-iron-chromium alloy specifically engineered with molybdenum and copper additions for exceptional corrosion resistance in aggressive environments. This datasheet focuses on the **Tube** product form, which is widely used in heat exchangers, condensers, and instrument lines where corrosion resistance is critical. The alloy's titanium stabilization prevents sensitization during welding and high-temperature service, making it suitable for various industrial applications. The designations **Alloy 825**, **Incoloy 825 Tube**, and **UNS N08825** all refer to this corrosion-resistant nickel-base alloy in tubular form. --- #### **2. Key Characteristics** * **Excellent General Corrosion Resistance:** Suitable for both oxidizing and reducing environments * **Superior Acid Resistance:** Outstanding performance in sulfuric, phosphoric, and other reducing acids * **Excellent Stress Corrosion Cracking (SCC) Resistance:** Highly resistant to chloride-induced SCC * **Pitting and Crevice Corrosion Resistance:** Enhanced by molybdenum content (2.5-3.5%) * **Good Heat Transfer Properties:** Suitable for heat exchanger applications * **Stabilized Against Sensitization:** Titanium addition prevents chromium carbide formation --- #### **3. Chemical Composition (Weight %)** The corrosion resistance of Alloy 825 Tube is ensured by its precise chemical balance. | Element | Minimum (%) | Maximum (%) | Key Function | | :--- | :--- | :--- | :--- | | **Nickel (Ni)** | 38.0 | 46.0 | Provides fundamental corrosion resistance in reducing environments | | **Chromium (Cr)** | 19.5 | 23.5 | Confers resistance to oxidizing environments | | **Iron (Fe)** | 22.0 min | Balance | Base element of the alloy | | **Molybdenum (Mo)** | 2.5 | 3.5 | Enhances pitting and crevice corrosion resistance | | **Copper (Cu)** | 1.5 | 3.0 | Provides resistance to reducing acids, particularly sulfuric acid | | **Titanium (Ti)** | 0.6 | 1.2 | Stabilizes against sensitization by forming titanium carbides | | **Carbon (C)** | - | 0.05 | Kept low to minimize carbide formation | | **Manganese (Mn)** | - | 1.00 | - | | **Sulfur (S)** | - | 0.03 | - | | **Silicon (Si)** | - | 0.05 | - | --- #### **4. Physical Properties (Typical)** | Property | Value | | :--- | :--- | | **Density** | 8.14 g/cm³ (0.294 lb/in³) | | **Melting Range** | 1370 - 1400 °C (2500 - 2550 °F) | | **Specific Heat (20°C)** | 440 J/kg·K | | **Thermal Conductivity** | 10.8 W/m·K (at 100°C) | | **Mean Coefficient of Thermal Expansion** | 14.0 μm/m·K (20 - 100°C) | | **Electrical Resistivity** | 1.12 μΩ·m | | **Modulus of Elasticity** | 196 GPa (28.4 x 10⁶ psi) | --- #### **5. Mechanical Properties (Typical for Annealed Condition)** * **Tensile Strength:** 655 MPa (95 ksi) min * **Yield Strength (0.2% Offset):** 275 MPa (40 ksi) min * **Elongation:** 30% min * **Hardness:** Rb 90 max --- #### **6. International Standards & Specifications** **Tube Products:** * **ASTM B163 / ASME SB163:** Standard Specification for Seamless Condenser and Heat-Exchanger Tubes * **ASTM B423 / ASME SB423:** Standard Specification for Seamless Pipe and Tube * **ASTM B704 / ASME SB704:** Standard Specification for Welded Tube * **ASTM B705 / ASME SB705:** Standard Specification for Welded Pipe and Tube * **ASTM B829:** Standard Specification for Seamless Nickel and Nickel Alloy Tubes **Dimensional Standards:** * **ASTM B751:** Standard Specification for General Requirements for Nickel and Nickel Alloy Seamless and Welded Tube **General Material Standards:** * **UNS:** N08825 * **EN (Euronorm):** EN 2.4858 (NiCr21Mo) * **DIN:** 2.4858 * **ISO:** 6207 (Nickel alloy tubes) --- #### **7. Applications** **Heat Exchanger Applications:** * Shell and tube heat exchangers for corrosive service * Condenser tubes in chemical processing * Cooler and heater tubes in refinery service * Evaporator and reboller tubes **Chemical Processing Industry:** * Process fluid transfer lines * Instrumentation and sampling lines * Reactor cooling coils * Acid production and handling systems **Oil & Gas Industry:** * Heat exchanger tubing in refinery service * Surface condenser tubing * Downhole instrumentation tubing * Process and utility heat exchangers **Power Generation:** * Condenser tubes for power plants * Feedwater heater tubes * Closed cooling water heat exchangers **Marine and Offshore:** * Seawater cooling systems * Heat exchanger tubes for marine applications * Desalination plant tubing **Other Applications:** * Nuclear fuel reprocessing equipment * Waste acid recovery systems * Pharmaceutical processing equipment --- #### **8. Fabrication Notes** * **Welding:** Use matching filler metals (AWS A5.14 ERNiFeCr-3) for GTAW, GMAW, and SAW processes * **Heat Treatment:** Solution anneal at **900-980°C (1650-1800°F)** followed by rapid cooling * **Tube Expansion:** Can be roller expanded into tube sheets using standard techniques * **Bending:** Can be cold bent using standard tube bending equipment * **Cleaning:** Proper cleaning is essential to maintain corrosion resistance --- **Disclaimer:** This technical information is for reference purposes. For critical applications, always consult the specific material certification and the latest version of the relevant standards. Actual properties may vary depending on manufacturing processes and heat treatment.

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 1940 gallon liquid totes Special package is available on request.