C71500 CuNi 70/30 Copper Nickel Alloy Seamless Tubing Desalination Plant Corrosion Resistant

1.Product Description

Copper-nickel alloy tubes are copper-based engineering pipes with nickel as the primary alloying element. The two most common commercial grades are:

• 90-10 Copper-Nickel Tube (C70600) — approximately 10% nickel, 1.0%~1.8% iron, the most widely used economic grade for seawater corrosion resistance.

• 70-30 Copper-Nickel Tube (C71500) — approximately 30% nickel, 0.4%~1.0% iron, a high-performance grade for severe corrosion and erosion service.

Material characteristics:

• Microstructure: single-phase face-centered cubic (FCC) solid solution with no risk of phase embrittlement.

• Manganese (Mn) added for deoxidization and auxiliary strengthening.

• Available forms: seamless (ASTM B466) and longitudinally welded (ASTM B467).

• Silver-white metallic luster; higher nickel content yields a whiter appearance; clean oxide-free internal bore.

• Manufacturing precision: cold-drawn or cold-rolled with precision-grade dimensional tolerances.

2.Product Applications

Copper-nickel tubes are widely used in marine engineering, power generation, chemical processing, and other industrial sectors. Typical applications include:

2.1 Marine & Shipbuilding

• Seawater cooling circulation systems (central coolers, plate heat exchanger piping)

• Firewater systems (deck fire rings)

• Ballast water treatment system piping

• Stern tube cooling lines

2.2 Power Generation

• Steam turbine condenser tube bundles in thermal power plants

• Auxiliary coolers in nuclear power stations

• Fin-tube base pipes in air-cooled condenser islands

• Feedwater heater tubes

2.3 Desalination

• Heating section tube bundles in Multi-Stage Flash (MSF) plants

• Evaporator tubes in Multi-Effect Distillation (MED) plants

• Brine heaters

2.4 Offshore Oil & Gas

• Platform utility piping (seawater, firewater, instrument air)

• Riser external anti-corrosion sheathing

• Subsea pipeline anode connection tubes

2.5 General Industry

• Vehicle pneumatic brake tubing

• High-purity water and organic solvent transfer piping

• Chemical piping for weak acids, weak alkalis, and saline media

• Compressed air system piping

3.Product Advantages

3.1 Extremely Low Corrosion Rate
In clean seawater, the annual corrosion rate of copper-nickel alloys is only 0.025~0.0025 mm. A dense, adherent oxide/nickel-rich composite protective film forms spontaneously on the surface, which continues to grow during seawater exposure and possesses self-healing capability — even if locally damaged, it can re-form within a short period.

3.2 Excellent Biofouling Resistance
Copper ions are continuously released at trace levels into the seawater, forming a biostatic layer on the tube surface that effectively prevents attachment of barnacles, algae, mollusks, and other marine organisms. Compared to stainless steel or titanium, systems using copper-nickel tubes can reduce chemical cleaning frequency by over 60%.

3.3 Superior Mechanical Properties and Strength-Toughness Balance

• Tensile strength: 275~345 MPa (annealed), elongation ≥25%, combining strength and ductility.

• 70-30 alloy offers higher inherent strength, suitable for high-pressure applications.

• Both grades can be further strengthened via cold working (light-drawn or hard-drawn).

3.4 Excellent Workability and Fabricability

• Compatible with manual TIG welding, orbital welding, oxy-acetylene welding, and brazing.

• Excellent cold bending performance — minimum bend radius as low as 1.5×OD without cracking.

• Tube ends can be flared, beaded, and mechanically expanded.

• No risk of stress corrosion cracking (SCC) — a significant advantage over austenitic stainless steels; minimal grain growth in the weld heat-affected zone.

3.5 Outstanding Life-Cycle Economy

• Design service life: 15~25 years, far superior to carbon steel with plastic coatings.

• Minimal corrosion allowance required — thinner wall thicknesses can be used, reducing structural weight.

• 100% recyclable material, meeting green engineering material requirements.

​

​4.Key Product Specifications

FAQ

1. Are you trading company or manufacturer ? We are manufacturer ,You can see the certification.

2.How long is your delivery time? Generally it is 5-10 days if the goods are in stock. or it is 15-20 days if the goods are not in stock, it is according to quantity.

3. Do you provide samples ? is it free or extra ? Yes, we could offer the sample for free charge but need pay the cost of freight.

4. What is your terms of payment ? Payment<=1000USD, 100% in advance. Payment>=1000USD, 50% T/T in advance ,balance before shippment.