Marine Copper Alloys
Copper is a very versatile metal, offering good resistance to corrosion in marine atmospheres and in seawater with moderate flow velocities. Its properties, both in terms of corrosion resistance and mechanical strength, can be further improved by alloying. There are many copper alloys suitable for marine service, with the main groups being: Coppers, Copper-nickels, Bronzes & Brasses. Copper alloys differ from other metals in that they have an inherent high resistance to biofouling, particularly macrofouling, which can eliminate the need for antifouling coatings or water treatment.
All copper alloys can be machined accurately and cost-effectively and to a good standard of tolerance and surface finish. Some copper alloys have excellent machinability as a primary attribute - specifically leaded brasses, which set the standard by which all other metals are judged. Other copper alloys are made with a variety of combinations of properties such as strength, wear resistance, anti-galling and cold formability. These may be less easily machined, but are still easier to machine than many other types of material.
For seawater systems, copper-nickel and aluminium bronze are often preferred, although other copper alloys are used in marine service and have their specific advantages. Copper-nickel alloys and aluminium bronzes are often preferred in seawater environments, used in heat exchangers/condensers, seawater piping, bearings, fasteners, propellers, shafts and offshore platform construction. Copper nickel alloys specifically have high resistance to chloride pitting, crevice corrosion and stress corrosion cracking. The addition of tin is used where bearing performance or high strength properties are required, such as stems, bushings and bearings. Copper-nickel-aluminium alloys are used for good anti-galling properties and resistance to hydrogen embrittlement.
Copper nickel has enhanced strength and corrosion resistance while maintaining a high inherent resistance to biofouling. The 90/10 copper nickel alloy is the most commonly used wrought copper alloy for marine engineering and can be found in seawater systems for naval, commercial, shipping, offshore oil & gas, multi-stage flash desalination and aquaculture. Alloys with higher nickel content, and those which are more highly alloyed with chromium, aluminium and tin are used where greater resistance to flow conditions, sand abrasion, wear and galling are required, as well as higher mechanical properties or castability.
While the more economical 90/10 copper nickel alloy is the most widely used, the 70/30 copper nickel alloy is stronger. Iron and manganese levels are important in optimising the corrosion resistance of both alloys.
Bronzes are used due to their superior resistance to ammonia stress corrosion. In general the higher the tin content the higher the corrosion resistance.
Aluminium bronzes are widely used as they combine high strength and corrosion resistance, used either in wrought or cast forms as pumps, valves, propellers, bushes, bearings, shafts and fasteners. The addition of nickel to these alloys provides increased ductility and improved castability, they have excellent resistance to cavitation and are often used for ship propellers.
Silicon bronzes are used for screws, nuts, bolts, washers and pins in marine environments. Brasses are also used due to their high tensile strength for applications such as propellers and shackles.
Spinodal Copper Nickel Tin Alloys
Hardiall® is a wrought spinodally hardened copper alloy CuNi15Sn8 (C72900) designed for high strength applications where toughness is required. It is non-magnetic and resists mechanical wear, galling, stress relaxation, corrosion and erosion.
It is easily machined into complex components and is environmentally friendly being both lead and beryllium free.
Lebronze alloys’ manufacturing process for Hardiall® is fully integrated: internal processes include casting, hot and cold working stage, heat treatment and non-destructive testing. Being fully integrated ensures reactivity and complete traceability.
Hardiall® Key Features & Benefits
- High strength & hardness
- Low friction
- Excellent lubricity
- Corrosion & erosion resistant
- Excellent wear resistance
- Excellent machinability
- Excellent galling resistance
- Pitting & spalling resistance
- No hydrogen embrittlement
- High performance at both elevated and sub-zero temperatures -193°F up to 572°F
- Dimensional stability
Hardiall® Physical Properties
Electrical Conductivity at 20°C (68°F)
Thermal Conductivity at 20°C to 200°C (68°F to 392°F)
38 (22) W/m/°C (Btu/ft/hr/°F)
Coefficient of Thermal Expansion at 20°C to 200°C (68°F to 392°F)
16.4 x 10-6 (9.1 x 10-6) Per °C (Per °F)
8.95 (0.323) g/cm3 (lb/in3)
Oil & Gas Applications
Hardiall® is used within the oil & gas industry thanks to its outstanding physical and mechanical properties in many varied components. Lebronze alloys has developed a full range of Hardiall® products to match the stringent demands of the oil & gas industry.
Bushings & Bearings
Hardiall® is used in bushings and bearings for drilling components. For such applications, Hardiall® demonstrates outstanding wear, corrosion, temperature and pressure resistance, thus providing a longer service life and a better total cost of ownership (TCO) compared to Beryllium Copper, as well as some Nickel or Cobalt based alloys. Hardiall® can be used in both offshore and onshore systems and in vertical or directional drilling products.
Couplings for Onshore Production Systems
Hardiall is also used in onshore oil pumps as sucker rod and valve rod guide bushing couplings. In such applications, where stainless steel is generally used, Hardiall® demonstrates excellent resistance to metal-to-metal wear, thus providing a reduction of failures and hence maintenance downtime.
For these applications Lebronze alloys’ integrated supply chain can propose ready-to-use products.
Hardiall® Products Portfolio
Hardiall® is available in various tempers and grades offering different mechanical properties. The following Hardiall® products are available for the oil & gas industry.
- HARDIALL® TX 90
- HARDIALL® TX 105
- HARDIALL® TX 110
- HARDIALL® TS 95
- HARDIALL® TS 120U
- HARDIALL® TS 130
- HARDIALL® TS 160U
- HARDIALL® TX 105
- HARDIALL® TX 110
All products can be ultrasonically tested at LBA upon customer request. Corrosion resistance according to NACE MR0175/ ISO 15156.
For more information, please click here.
Naval Engineering Tube>
NES may require specific testing procedures to include hydrostatic and ultrasonic testing together with more general criteria such as dimensional tolerances.
Copper Nickel & Gunmetal Fittings
Butt Weld Fittings (90/10 CUNI & Copper)
Flanges (90/10 CUNI & Gunmetal)
Machined Fittings (90/10 CUNI & LG4 MHD Type/GHD Type)
Copper Nickel Press Fit Systems
The pressfitting system was developed for pipes carrying sea water in shipbuilding and other marine applications. It combines the advantages of stainless steel, carbon steel and copper systems together with high sea water corrosion resistance, resistance to stress corrosion cracking and high strength. The pressfitting system offers a range of sizes from DN12 to DN102.
Copper nickel press fitting systems are quick to use and have lower labour costs in comparison to conventional connection technology. It is a simple, clean and economical system as the seal rings are protected from dirt and no consumables such as oxygen or gas are required. This system has been in use for over 30 years, is extremely safe and there is no confusion with third-party products. There is no danger of fire as welding and soldering are not necessary and products can be easily identified. Application ranges are easily identified by the plug colours, product materials can be distinguished by the indicator colours and unpressed connections are also easily identifiable.
Technical data sheets are available for the following:
- Copper nickel pipes pressure system options for shipbuilding
- Permissable working pressures for 90/10 tube
- Comparison of costs of various pipeline materials
- Corrosion rates
- Comparison of properties of various pipeline materials
For further information please contact your local Righton Blackburns Service Centre.
Copper Alloy Marine Materials At a Glance
- DIN BSEN 90 / 10
- NES 779 DEFSTAN 02-878 (90/10 Pipe & Fittings)
- NES 835/DEFSTAN 02-835 (High Strength Rod)
- NES 780 DEFSTAN 02-878 (70/30 Pipe & Fittings)
- NES 780 DEFSTAN 02-879 (70/30 Rod)