70 30 Cu Ni Copper-Nickel Alloy, UNS C71500,E FORU

### **70-30 Copper-Nickel Alloy (UNS C71500)** #### **Overview** UNS C71500 is a **70-30 copper-nickel alloy**, consisting of approximately 70% copper and 30% nickel. It is one of the most important and widely used alloys in the copper-nickel family, renowned for its exceptional resistance to seawater corrosion and marine biofouling. The alloy's excellent corrosion resistance is attributed to the formation of a protective, stable oxide film on its surface. Furthermore, C71500 offers good fabricability, high thermal conductivity, and superior resistance to stress-corrosion cracking, making it a premier material for marine and industrial applications. --- #### **Chemical Composition (Weight % - Typical)** The chemical composition of UNS C71500 is carefully controlled to optimize its corrosion resistance and mechanical properties. | Element | Content (%) | | :--- | :--- | | **Copper (Cu)** | **Balance** (approx. 65.0 - 69.0) | | **Nickel (Ni)** | **29.0 - 33.0** | | **Iron (Fe)** | **0.40 - 1.0** | | **Manganese (Mn)** | **0.40 - 1.0** | | **Zinc (Zn)** | ≤ 1.0 | | **Lead (Pb)** | ≤ 0.05 | | **Carbon (C)** | ≤ 0.05 | | **Other (Total)** | ≤ 0.2 | *The iron and manganese additions are critical; they enhance the overall corrosion resistance, particularly improving resistance to impingement attack and pitting in high-velocity seawater.* --- #### **Physical Properties** The following table outlines the key physical properties of UNS C71500. | Property | Value | | :--- | :--- | | **Density** | 8.94 g/cm³ (0.323 lb/in³) | | **Melting Point (Liquidus)** | 1230 °C (2250 °F) | | **Specific Heat (20°C)** | 377 J/kg·K | | **Thermal Conductivity** | 29 W/m·K (at 20°C) | | **Electrical Conductivity** | ~4.5 % IACS (International Annealed Copper Standard) | | **Mean Coefficient of Thermal Expansion** | 16.2 μm/m·°C (20-300°C) | | **Modulus of Elasticity (Tension)** | 150 GPa (22 x 10⁶ psi) | --- #### **Mechanical Properties (Typical for Annealed Condition)** Mechanical properties can vary with product form and temper. The following are typical values for annealed material. | Property | Typical Value | | :--- | :--- | | **Tensile Strength** | 380 - 480 MPa (55 - 70 ksi) | | **Yield Strength (0.2% Offset)** | 140 - 210 MPa (20 - 30 ksi) | | **Elongation (in 2 inches / 50 mm)** | 45% - 35% | | **Hardness (Rockwell B)** | 45 - 65 HRB | --- #### **Key Characteristics & Applications** **Key Characteristics:** 1. **Excellent Corrosion Resistance:** Superior resistance to seawater, brackish water, and a wide range of industrial chemicals. It is highly resistant to stress-corrosion cracking. 2. **Biofouling Resistance:** The corrosion product layer on the surface inhibits the attachment and growth of marine organisms, reducing maintenance costs. 3. **Good Fabricability:** Can be readily fabricated and welded using common techniques such as gas tungsten arc welding (GTAW/TIG) and gas metal arc welding (GMAW/MIG). 4. **High Thermal Conductivity:** Makes it an excellent material for heat exchangers and condensers. 5. **Antimicrobial Properties:** Copper-nickel alloys have inherent antimicrobial (biocidal) properties, which is beneficial in marine and healthcare environments. **Typical Applications:** * **Marine Engineering:** * Seawater piping systems * Condenser and heat exchanger tubes * Desalination plant components * Boat hulls and sheathing * Offshore platform piping and splash zone sheathing * **Power Generation:** Condenser tubes in fossil and nuclear power plants that use seawater or brackish water for cooling. * **Chemical Processing:** Vessels, heat exchangers, and piping handling salts, non-oxidizing acids, and alkalis. * **Oil & Gas:** Components in offshore systems exposed to seawater. --- #### **International Standards** UNS C71500 is covered by numerous international standards for various product forms. | Product Form | ASTM (USA) | ASME (USA) | EN (European) | DIN (German) | UNS | | :--- | :--- | :--- | :--- | :--- | :--- | | **Plate, Sheet, Strip** | ASTM B171 | SB-171 | EN CW354H (CuNi30Fe) | 2.0882 | C71500 | | **Seamless Pipe & Tube** | ASTM B466 / B467 | SB-466 / SB-467 | EN CW354H (CuNi30Fe) | 2.0882 | C71500 | | **Bar, Rod** | ASTM B151 | SB-151 | EN CW354H (CuNi30Fe) | 2.0882 | C71500 | | **Forgings** | ASTM B283 | - | EN CW354H (CuNi30Fe) | 2.0882 | C71500 | | **Fittings** | ASTM B366 | - | EN CW354H (CuNi30Fe) | 2.0882 | C71500 | **Note:** The primary European standard designation is **EN CW354H**, which corresponds to the material number **CuNi30Fe**. The common industry name is **70/30 CuNi** or **CN107**. --- #### **Summary** In summary, **70-30 Copper-Nickel Alloy (UNS C71500)** is a high-performance engineering material specifically designed for long-term service in aggressive marine and industrial environments. Its unbeatable combination of corrosion resistance, biofouling resistance, and excellent fabricability has made it the global standard for critical applications like seawater cooling systems, desalination plants, and offshore oil and gas infrastructure. Its widespread acceptance and codification in major international standards ensure its reliability and availability for demanding projects worldwide.

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 3196 gallon liquid totes Special package is available on request.