70-30 UNS C96400 Nickel-Copper Alloy,Cast UNS C96400; 1

### **Product Introduction: 70-30 Copper-Nickel Alloy (UNS C96400)** **Overview** UNS C96400 is a high-strength, nickel-copper alloy commonly referred to as **70-30 Copper-Nickel** or **CuNi30**. It is a cast version of the widely used wrought 70/30 cupronickel alloy. This alloy is renowned for its exceptional resistance to seawater corrosion, outstanding biofouling resistance, and excellent erosion-corrosion resistance. It combines the classic marine corrosion resistance of the 70-30 composition with the design flexibility of casting, making it an ideal material for complex-shaped components in marine, offshore, and power generation industries where longevity and reliability in saltwater service are paramount. --- #### **Chemical Composition (Typical % by Weight, per ASTM B369)** The composition of C96400 is balanced to optimize seawater corrosion resistance and mechanical properties. | Element | Content (%) | Role & Benefit | | :--- | :--- | :--- | | **Copper (Cu)** | Balance | Forms the matrix of the alloy. | | **Nickel (Ni)** | 29.0 - 33.0 | The primary alloying element. Significantly enhances strength and provides the foundation for excellent corrosion and fouling resistance in seawater. | | **Iron (Fe)** | 0.40 - 1.0 | A critical addition. Improves resistance to impingement attack and erosion-corrosion in high-velocity seawater. | | **Manganese (Mn)**| 0.50 - 1.5 | Acts as a deoxidizer during melting, enhances castability, and improves strength and hot workability. | | **Lead (Pb)** | 0.02 max | A detrimental element kept very low to avoid hot shortness and preserve mechanical properties. | | **Zinc (Zn)** | 0.50 max | A residual element, kept low to avoid negative impacts on corrosion resistance. | | **Carbon (C)** | 0.15 max | A residual element. | | **Silicon (Si)** | 0.15 max | A residual deoxidizer. | | **Phosphorus (P)**| 0.02 max | Kept low to maintain good ductility and toughness. | | **Sulfur (S)** | 0.02 max | A detrimental element kept to a minimum to prevent hot cracking. | --- #### **Physical & Mechanical Properties (Typical)** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.94 g/cm³ (0.323 lb/in³) | | **Melting Range** | 1170 - 1240 °C (2140 - 2265 °F) | | **Thermal Conductivity**| 29 W/m·K (200 BTU·in/hr·ft²·°F) @ 20°C | | **Thermal Expansion** | 16.0 μm/m·°C (8.9 μin/in·°F) @ 20-100°C | | **Modulus of Elasticity** | 152 GPa (22 x 10⁶ psi) | | **Tensile Strength (As-Cast)** | 414 MPa (60 ksi) min | | **Yield Strength (0.5% Ext. Under Load, As-Cast)** | 172 MPa (25 ksi) min | | **Elongation (As-Cast)** | 20% min | *Note: Properties can be enhanced by heat treatment (e.g., annealing).* --- #### **International Standards and Specifications** UNS C96400 is recognized by several key international and military standards. * **ASTM B369:** Standard Specification for Copper-Nickel Alloy Castings. * **MIL-C-20159:** Military Specification for Castings, Copper-Nickel Alloy (This spec covers 70-30 CuNi castings like C96400). * **UNS C96400:** Unified Numbering System designation. * **ISO 16424 (CuNi30Fe):** Corresponding international designation. * **ASME SB-369:** Approved for use in ASME Boiler and Pressure Vessel Code applications. --- #### **Product Applications** C96400 castings are primarily used in marine and power generation systems where contact with seawater is continuous. 1. **Marine & Shipbuilding:** * **Propeller Blades** and **Propeller Hubs** * **Seawater Pump Casings, Impellers, and Bow Thrusters** * **Valve Bodies, Strainers, and Fittings** for seawater piping systems * **Desalination Plant Components** 2. **Offshore Oil & Gas:** * **Seawater System Components** on platforms and FPSOs (e.g., pump casings, manifold valves). * **Heat Exchanger Castings** for seawater cooling. 3. **Power Generation:** * **Condenser Water Boxes, Tube Sheets, and End Covers** in coastal and nuclear power plants that use seawater for cooling. * **Pump Components** for circulating water systems. 4. **Marine Engineering:** * Components for offshore structures, sonar domes, and other submerged applications. #### **Key Advantages** * **Superior Seawater Corrosion Resistance:** Highly resistant to general corrosion, pitting, and crevice corrosion in both quiet and high-velocity seawater. * **Excellent Biofouling Resistance:** The corrosion film that forms is toxic to marine organisms, significantly reducing biofouling. * * **High Erosion-Corrosion Resistance:** The combination of nickel and iron provides exceptional resistance to impingement attack from turbulent or high-velocity water containing sand or air bubbles. * **Good Fabricability:** Castings can be readily welded and machined using standard techniques for copper-nickel alloys. **Conclusion** UNS C96400 (70-30 Copper-Nickel) is a premier cast alloy for severe marine service. Its proven track record in naval and commercial vessels, offshore platforms, and power plants underscores its reliability and performance. For engineers designing critical seawater-handling components that require long service life, minimal maintenance, and resistance to the harsh marine environment, C96400 castings offer a robust and standardized solution, fully backed by ASTM B369 and military specifications like MIL-C-20159.

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 3408 gallon liquid totes Special package is available on request.