What makes Special Metal Alloys the leading global supplier of copper-nickel tubes?

Special Metal Alloys has built a strong global reputation as a premier supplier of copper-nickel, also called cupronickel, tubing and a comprehensive range of speciality nickel alloy products.

With an extensive distribution network, we supply cupronickel tubes, pipes, fittings, and related products to customers worldwide, ensuring availability and prompt delivery across global markets.

We provide a variety of quality-certified copper-nickel tubes tailored to meet the needs of various specialised industries.

Our highly trained and experienced team offers expert guidance on the appropriate chemical composition, material behaviour, performance, and manufacturing standards required for high-risk and demanding projects. 

Special Metal Alloys closely monitors market trends and customer demand for different copper-nickel and cupronickel alloy grades to ensure we meet evolving industry requirements.

This expertise includes downstream processing and fabrication in sectors such as oil and petroleum, nuclear, defence, medical, pharmaceutical, and chemical industries, across all types of climates and operational environments.

All our products undergo meticulous testing and are subject to strict industry quality controls. Additionally, our reliable logistics partners ensure seamless import-export operations and timely delivery anywhere in the world.

Special Metal Alloys provides transparent pricing and stays updated on copper price fluctuations via the London Metal Exchange.

Contact us for a quote online, call +44 (0)161 278 2386 or email sales@specialmetalalloys.co.uk.

Our copper-nickel tube product range

We offer a complete range of copper-nickel tubing in fixed lengths or coils, available in various diameters and wall thicknesses, sourced from our central stock through forward orders from the most reputable manufacturing mills.

Our product range also includes cupronickel plates, bars, pipes, and flanges, ensuring comprehensive supply options for all your copper-nickel requirements.

Grades of our copper-nickel tubes

Rigorous, standardised industry specifications, such as the UNS designations, ASTM standards, and ASME standards, guarantee the quality, reliability, safety, and performance criteria of our products. These standards regulate the chemical composition, mechanical properties, and manufacturing processes.

Depending on the specific requirements of your projects, we supply all the various grades of copper-nickel tubing, also known as cupronickel tubing.

The two grades used primarily in marine conditions

The two most commonly used grades are 90/10 and 70/30, part of the typical 10 copper-nickel alloys. These figures indicate the ratios of copper and nickel in the chemical composition of the final products and are widely used in piping, heat exchangers, and marine applications.

90/10 Cu-Ni (UNS C70600), consisting of 90% copper and 10% nickel, is a cost-effective marine option. It provides an excellent balance of mechanical properties, thermal conductivity, formability, and corrosion resistance. Its resistance to stress and erosion makes it particularly suitable for applications requiring high durability.

70/30 Cu-Ni (UNS C71500), comprising 70% copper and 30% nickel, is valued for its exceptional strength and corrosion resistance, especially in seawater and harsh marine environments. The 70/30 alloy is stronger and can withstand higher seawater velocities compared to the 90/10 alloy.

Other grades include:

80/20 copper-nickel, which is a less common grade that serves as a middle ground between 90/10 and 70/30, particularly in environments with higher water velocities and corrosive elements.

A specialised grade like UNS C71640 (66-30-2-2) is a robust modified 70/30 alloy that includes added iron and manganese, enhancing its resistance to impingement erosion in high-velocity seawater and environments with suspended solids.

Additional high-strength speciality grades, such as C72900 (Cu-Ni-Al), incorporate aluminium, while others, like Cu-Ni-Sn, use tin.

Sizes and pressure classes of our copper-nickel tubes

At Special Metal Alloys, we offer an extensive range of copper-nickel tubes designed to meet the rigorous demands of industries such as shipbuilding, offshore oil and gas, power generation, and desalination plants. 

Our copper-nickel tubing is available in standard sizes from 1/2 inch up to 20 inches in diameter, with a variety of wall thicknesses to ensure excellent resistance to seawater corrosion and long-term durability in even the harshest saltwater environments.

Our copper-nickel tubes are engineered to deliver outstanding corrosion resistance, making them the preferred choice for seawater systems, heat exchangers, and applications where exposure to brine water and aggressive marine conditions is unavoidable.

We supply tubes in pressure classes of 14 BAR, 16 BAR, and 20 BAR, as well as military-grade specifications such as MIL-T-16420K, which includes Class 200, Class 500, and Class 700 pressure ratings. This ensures our products can withstand the high pressures and demanding operational requirements found in desalination plants, offshore platforms, and power generation facilities.

As a leading manufacturer and exporter, we provide copper-nickel tubes in a wide range of alloys, including the widely used 90/10 and 70/30 grades. These alloys are commonly specified for their inherent resistance to seawater corrosion, biofouling, and mechanical wear, making them ideal for the manufacture of tubes, pipes, fittings, and flanges. 

Our products are trusted for their durability and reliability in critical systems across the oil and gas markets, wastewater treatment plants, and marine engineering projects.

We offer copper-nickel tubing in both coils and fixed lengths, with a comprehensive selection of sizes and specifications to suit your project requirements. All our copper-nickel tubes are manufactured in accordance with international standards such as ASTM, ASME, and DIN, ensuring consistent quality and performance. 

Our commitment to excellence extends to providing customised solutions for specialised applications, allowing us to meet the unique needs of our customers worldwide.

With a strong presence in the UK, Germany, Italy, France, Spain, and beyond, Special Metal Alloys is dedicated to delivering high-quality copper-nickel products and exceptional service. Our expert team is always available to assist with technical advice, product selection, and tailored manufacturing to ensure you receive the right solution for your application. 

Whether you require standard sizes or bespoke specifications, we are committed to providing reliable, high-performance copper-nickel tubes that meet the highest standards of safety, quality, and corrosion resistance.

Industry standards we adhere to

Standards such as ASTM B466, ASTM B467, and ASME SB466 define specific performance criteria for marine environments. Manufacturers and suppliers must comply with these stringent standards when providing copper-nickel tubes to contractors and end users.

How is copper-nickel tubing manufactured?

Copper, nickel, iron, and manganese are melted in a furnace in different combinations and ratios according to the grade, and then cast into billets for seamless tubes or sheets for welded tubes.

Further processing may involve either hot or cold working steps to achieve the precise shape and dimensions needed for their specific applications.

To increase ductility and improve workability, the tubes can be annealed, making them more stable and less brittle.

How is seamless tubing manufactured?

Hot-rolling

• Round billets, heated to about 1300°C, are pierced along their axis with a cone-shaped plug or a mandrel while being cross-rolled between rollers (hot-rolled), creating a hollow shell.
• The shell is stretched, and its walls are thinned using rollers until it reaches the required length and thickness.
• Several rolling stages accomplish the eventual dimensions, and the tubes are straightened to remove any warps.

Extrusion

• Heated billets are pierced and forced through a series of dies to achieve their desired diameters and wall thickness.
• The die opening forms the outer profile, while a mandrel forms the inner profile, producing a seamless tube with uniform wall thickness.
• This process is followed by passing these tubes through several rolling stages, or cold drawing the tube through dies to achieve precise dimensions.
• Extrusion is typically used for complex shapes or high-strength alloy tubes that are difficult to roll.

How is welded tubing manufactured?

• Flat metal strips of the right thickness are cut into the required width and rolled into cylindrical shapes. 
• The two edges are lined up and fused by specific welding techniques, including:
  • High-frequency (electric resistance) welding, often with a rotating electrode. This process is used for general-purpose tubing.
  • Copper-nickel tubes and other alloys are often welded with a laser beam for precise welding.
  • Gas tungsten arc welding uses a non-consumable tungsten electrode to produce high-quality welds in stainless steel.
  • Submerged arc welding is used for thick-walled tubes, usually in a spiral or longitudinal weld pattern.
  • The weld bead is usually removed and smoothed out. In some cases, the weld is subjected to annealing to enhance its resistance to stress and corrosion.

What is the difference between copper-nickel pipe and copper-nickel tubing?

• While the terms “pipe” and “tube” are often used interchangeably, they actually refer to two distinct engineering standards.
• Copper-nickel pipes and tubes are produced using similar core processes, such as extrusion, drawing, and occasionally welding. However, there are significant differences in their specifications and tolerances.
• They are measured in different ways, and this distinction is vital for ensuring proper fitting of components. Copper-nickel pipes are measured by Nominal Pipe Size (NPS) and Schedule, which reflect the interior diameter rather than the actual physical dimensions. In contrast, copper-nickel tubing is measured by its actual outside diameter (OD) and wall thickness.
• Pipe wall thickness is referred to as a Schedule or a Class, particularly for copper-nickel applications in the naval industry. In contrast, tubing wall thickness is measured in inches or millimetres and occasionally by Gauge (BWG – Birmingham Wire Gauge).
• Pipes are always round since they are mainly designed to transport fluids (water, oil, gas) over long distances, with internal flow capacity being more crucial than having a perfectly smooth or precise exterior.
• On the other hand, tubing can be round, square, or rectangular, and is produced to much tighter tolerances because it is often utilised in heat exchangers or hydraulic systems, where a precise fit into fittings or manifolds is essential.
• The choice between copper-nickel (Cu-Ni) pipes and tubes primarily depends on the intended application (conveyance versus heat transfer), structural needs, and dimensional specifications. Although both provide excellent corrosion resistance, especially in seawater, they are designed and utilised differently.

Inherent corrosion resistance of copper-nickel tubes in saltwater environments and seawater systems.

Chemical composition:

Unlike some other materials, copper-nickel alloys are naturally resistant to chloride stress-corrosion cracking.

The following outstanding qualities make them highly durable and reliable in marine and industrial environments where exposure to seawater, saltwater, and high-velocity fluids is common:

• Its outstanding erosion resistance.
• High strength-to-weight ratio and the ability to maintain structural integrity under high pressure and extreme temperatures.
• Its ability to withstand biofouling.
• Robust mechanical properties and inherent resistance to deformation and metal fatigue, which enhance its structural integrity, ductility, and formability.
• Excellent thermal conductivity allows it to withstand extreme temperatures and resist scaling under prolonged exposure to heat, and to resist brittle fracture under prolonged exposure to extreme cold.
• It maintains functional electrical properties in wet, high-salinity environments.
• Its excellent weldability and formability provide significant manufacturing and fabrication benefits and design versatility.
• It is chemically highly compatible with a large variety of metals, elements, and compounds, making it extremely versatile, without unwanted chemical reactions.

The qualities added by each element of the alloy

Copper serves as the base metal, providing natural corrosion resistance and anti-biofouling properties because copper ions inhibit the attachment and growth of marine organisms like barnacles and algae.

Nickel, the primary alloying element, significantly boosts resistance to saltwater corrosion, pitting, and overall degradation.

Adding iron (typically from 0.4% to 1.8%) greatly enhances resistance to erosion-corrosion and impingement attack in flowing seawater. This effectively increases resilience against high-velocity water while maintaining the protective film.

Manganese functions as a deoxidiser during manufacturing and contributes to improved resistance.

Protective cuprous oxide film

In addition to its natural corrosion resistance, it creates a self-healing protective cuprous oxide film that shields the surface against corrosive elements and repairs itself if scratched to provide ongoing protection. This film enhances corrosion resistance, eliminates the need for extra coatings, and reduces maintenance requirements.

This is a spontaneous chemical reaction with seawater that starts immediately and matures fully over a period of 2 to 3 months. The film can be further enhanced by adding copper hydroxychloride and cupric oxide.

Testing of Nickel Tubes

To ensure copper-nickel tubes meet international safety and quality standards, they are thoroughly tested by a combination of non-destructive tests that do not damage the tube.

Non-destructive testing includes:

• Electromagnetic induction, known as eddy current inspection, to detect internal flaws and ensure wall consistency,
• Hydrostatic pressure testing to identify leaks and assess burst resistance,
• Detailed visual inspections using specialised lighting and magnification to spot surface defects such as oxidation, discolouration, or cracks,
• To verify compliance with tolerances, wall thickness, outer diameter, and length are accurately measured using laser or digital micrometers.

Mechanical tests include:

• Metallurgical analysis to confirm the precise alloy composition, as well as hardness and tensile strength assessments, corrosion resistance evaluations,
• Mercurous nitrate tests to check for internal stress,
• Flattening to identify cracks or flaws,
• Flaring tests to evaluate ductility and structural integrity

Applications for copper-nickel tubes

Their exceptional corrosion resistance in saltwater, combined with high strength, durability, excellent thermal conductivity, and biostatic properties, is crucial for operational performance and safety in key industries such as shipbuilding, chemical and pharmaceutical processing, desalination plants, offshore structures, and coastal architecture.

Cupronickel tubes are widely used in seawater piping systems due to their outstanding corrosion resistance. Copper-nickel tubes can also be fabricated into a wide variety of fittings thanks to their excellent ductility.

In the case where specific sizes or products are not in stock, we offer custom manufacturing or expedited delivery to ensure your requirements are met quickly and efficiently.

Some of the most important applications include:

Desalination plants:

• Heat exchangers and condensers,
• Brine heaters,
• Seawater transport,
• Preheating and heat recovery systems,
• Cooling systems.

Offshore oil and gas:

• Piping in seawater cooling systems,
• Fire suppression and sprinkler systems,
• Heat exchangers and condensers,
• Seawater intake systems and piping,
• Hydraulic and pneumatic lines,
• Desalination units,
• Bilge and ballast systems,
• Deluge systems,
• Instrument tubing.

Chemical and pharmaceutical processing

• Heat transfer equipment like heat exchangers, condensers, and evaporators,
• Cooling systems for seawater or brackish water,
• Piping for processing and transporting aggressive chemicals, often at high temperatures,
• Distillation columns,
• Desalination and handling brine in harsh conditions.

Shipbuilding

• Piping for seawater cooling systems,
• Ballast, bilge, and fire suppression.
• Heat exchangers and condensers,
• Steam and onboard desalination,
• Hydraulic lines,
• Engine cooling and oil lube systems,
• Fuel and gas lines.

Supply and delivery

Prices, lead times, and delivery times vary based on factors such as complexity, mill quantities, minimum order requirements, customisation needed for specific projects, and the availability of stock from suppliers.

Copper-nickel pipes are available in various sizes ranging from 1/2″ to 20″. If not in stock, copper-nickel pipes can be manufactured in 3-4 days, and urgent orders can be delivered within 7 days. Copper-nickel tubes also come with customisation capabilities, such as custom lengths and specialised U-bend forms for heat exchangers. Ensuring accurate dimensions for outer diameter, wall thickness, and length is vital to avoid costly errors in the installation of copper-nickel tubes.

To provide accurate quotes, we need details such as outer diameter (OD), wall thickness, length, and alloy grade.

Special Metal Alloys UK Ltd offers top-quality copper-nickel tubing to any specification, delivered globally with short turnaround times, thanks to our dependable mills and logistics partners. For any enquiries or custom requirements, please contact our sales team.Contact us for a quote online, call +44 (0)161 278 2386 or email sales@specialmetalalloys.co.uk.