CuNi 70/30 Copper Nickel Round Bar for Condenser Tube Plates UNS C71500

Product Specification

CuNi 70/30 Copper Nickel Round Bar for Condenser Tube Plates UNS C71500

1.Product Description

Copper nickel bar (commonly known as cupronickel bar) is a binary alloy solid rod based on copper with nickel as the primary additive element, renowned as the "marine metal" for its exceptional seawater corrosion resistance and stable resistance characteristics. Manufactured from high-purity cathode copper and electrolytic nickel through vacuum induction melting, hot extrusion, multi-pass cold drawing, precision straightening and mirror polishing, the product features a dense and uniform microstructure, high dimensional accuracy, and excellent surface quality. Strictly compliant with ASTM B151/B151M, EN 12163, GB/T 4423, and ISO 9725, the bars offer stable and reliable quality to meet the engineering material selection needs of global customers.

2.Product Applications

The application scenarios of copper nickel bars are closely tied to grade selection, with different nickel contents corresponding to distinct typical uses:

• CuNi10 (low nickel, ~10% Ni) – focused on electrical and precision manufacturing:heating resistance elements for low-voltage electrical devices, thermal overload relays, shunts, thermocouple protection tubes, as well as automotive hydraulic brake hard tubes and precision shafts for instruments. Moderate nickel content provides a good balance between resistivity and machinability.

• CuNi19 (medium-low nickel, ~19% Ni) – bridging electrical and general corrosion-resistant structures:applications requiring higher resistivity and moderate corrosion resistance, such as resistance box winding cores, medium-temperature measurement elements, and chemical instrument fittings.

• C70600 / 90-10 (medium nickel, ~30% Ni equivalent) – focused on marine and heat exchange engineering:seawater cooling pipelines, heat exchanger tube sheets, pump and valve bushings, propeller shaft sleeves, marine fasteners, desalination plant components. This is the most widely applied copper nickel grade in marine engineering.

• C71500 / 70-30 (high nickel, 29~33% Ni) – focused on severe corrosion and deep-sea applications:deep-sea equipment hydraulic valve bodies, high-velocity seawater pump shafts, LNG cryogenic transfer fittings, chemical reactor agitator shafts, high-temperature steam pipeline flanges. Suitable for the most demanding combined corrosion and cryogenic conditions.

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​3.Product Advantages

1. Seawater corrosion resistance and long-term service capability:In flowing seawater and chloride environments, the surface self-generates a dense, stable oxide film with extremely low corrosion rates (C70600 uniform corrosion rate in seawater <0.025 mm/year). Design service life of 25–30 years in marine engineering equipment, eliminating frequent replacement and significantly reducing maintenance costs throughout the life cycle.

2. High strength-toughness balance for complex loads:Tensile strength ranges 380–620 MPa (C71500 typical ≥480 MPa), with elongation generally above 30%, combining high strength with excellent plasticity, outstanding impact and fatigue resistance. Maintains structural integrity under deep-sea high pressure, high-temperature steam, and alternating vibration conditions.

3. Erosion and cavitation resistance for dynamic conditions:Maintains low corrosion rates in high-velocity seawater (≥5 m/s) and sand-containing media, with outstanding cavitation peeling resistance. Particularly suitable for pump impeller shafts, valve cores, elbow pipelines and other fluid machinery critical components, effectively extending equipment overhaul intervals.

4. Excellent workability and joining adaptability:Smooth machinability for turning, milling, drilling and tapping with low tool wear; adaptable to TIG welding, resistance welding, brazing and hot bending. Weld joint strength matches the base material well, with no special process requirements, facilitating the manufacture of various complex assemblies.

5. Wide temperature stability for extreme conditions:From -250°C cryogenic to +350°C high temperature, mechanical properties change gradually with no ductile-to-brittle transition point, and good high-temperature oxidation resistance. Combines both thermal and electrical functions – thermal conductivity 29–75 W/m·K, resistivity 0.24–0.50 μΩ·m – simultaneously meeting heat exchange and electrical control requirements.

​4.Product  Specifications

FAQ

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