What are the grades of copper-nickel - Knowledge

1.What are the grades of copper-nickel?

Copper-nickel alloys have well-established grading systems, mainly designated by standards such as the Unified Numbering System (UNS) and European CW codes. These grades are differentiated by their chemical compositions and performance, making them suitable for diverse application scenarios. The common grades are detailed as follows

90-10 Copper-Nickel (UNS C70600, CW352H)

This is the most widely used wrought copper-nickel grade, consisting of 10% nickel and 90% copper. It also contains trace amounts of iron and manganese, which enhance its resistance to localized corrosion and adaptability to seawater flow. It is extensively applied in seawater systems of naval and commercial ships, offshore oil and gas production equipment, desalination plants, and aquaculture facilities.70-30 Copper-Nickel (UNS C71500, CW354H)

Composed of 30% nickel and 70% copper, this grade is stronger than 90-10 copper-nickel and can withstand higher flow velocities. Similar to the 90 - 10 grade, it contains controlled small amounts of iron and manganese to optimize its corrosion resistance. Initially developed for naval applications, it is now widely used in multi-stage flash desalination units.66-30-2-2 Copper-Nickel (UNS C71640, CW353H)

It is a modified version of the 70-30 copper-nickel alloy, with 2% iron and 2% manganese added to its composition. It can endure higher flow rates than both the 90 - 10 and 70 - 30 grades. Its primary product form is condenser tubing, and it performs exceptionally well in multi-stage flash desalination plants, especially in heat rejection and brine heater sections, due to its strong resistance to erosion corrosion caused by suspended solids.Copper-Nickel-Chromium (UNS C72200)

This wrought alloy contains 16% nickel and 0.5% chromium. It is designed to withstand higher flow velocities in condenser tubing. There is also a cast variant with 30% nickel and 2% chromium, specified in the UK Defence Standard 02 - 824. This cast grade is often used as a substitute for nickel-aluminum bronze in manufacturing cast valve bodies and pump components.Copper-Nickel-Aluminum Alloys

By adding aluminum, these alloys achieve enhanced strength through precipitation hardening, with nickel-aluminum intermetallic compounds (gamma prime, Ni₃Al) as the key strengthening phase. They are utilized to produce high-strength components such as shafts, bearing brushes, bolts, pump and valve trim, gears, and fasteners.Nickel Silvers (C73500 - C79999)

These are copper-nickel-zinc ternary alloys categorized under wrought copper alloys

. Despite their name, they contain no silver. Their nickel content varies, and they are widely used in decorative items, musical instruments, and precision mechanical parts due to their attractive luster and good mechanical processing properties.