Cupronickel is a copper-nickel alloy resistant to corrosion. Its resistance to oxidation and chemical destruction allows it to be used as a structural material in products that are subject to contact with aggressive environments. The page contains a description of cupronickel: physical properties, application areas, grades, and types of products.
Basic information about cupronickel
Cupronickel is a corrosion-resistant copper-nickel alloy. The main components are copper (Cu) and nickel (Ni), and a small amount of manganese (Mn) and iron (Fe) may be present. It has high corrosion resistance and good plasticity. This material is used in shipbuilding, medical industry, in hardware engineering and in the production of tableware and coins.
History of creation
Cupronickel was developed by French scientists Maillot and Chorier. It was named after its creators by combining their surnames.
Cupronickel properties
The main practical useful property is its high corrosion resistance in sea and fresh water, the atmosphere of dry gases. Among the mechanical properties of the alloy, it is worth noting the high strength, which is provided by the presence of nickel in its composition. The higher the percentage of Ni in a particular grade of cupronickel, the higher its strength. The described material has good plasticity, which belongs to the group of technological properties. This allows processing of the described alloy under pressure both in hot and cold conditions. It is also can be soldered and is well polished.
Property
MNZHMc30-1-1
MN19
Density, g/cm3
8.9
8.9
Melting point, °С
1230
1190
Specific electric resistance, Ohms·m
420·10-9
287·10-9
Magnetic field
Not magnetic
Not magnetic
Hardness, HB
58.8-68.9 (after annealing) 98
69 (after annealing) 117
Temperature coefficient of linear expansion, °С-1 in the range of 20-100 °С
16·10-6
16·10-6
Temperature coefficient of electrical resistance, °C-1
0.1·10-3
0.1·10-3
Cupronickel grades
The most common grades are MN19 and MNZHMc30-1-1. The industry also produces MN16, MN25, MNZHMc10-1-1 alloys. Cupronickel of the grade MN19 contains nickel + cobalt (Ni + Co) - 18-20%, copper (Cu) - the rest (approximately 78.5-82%), a small amount of manganese (Mn) and iron (Fe). MNZHMc30-1-1 alloy contains a larger amount of nickel + cobalt (Ni + Co), manganese (Mn) and iron (Fe): 29-33%, 0,5-1%, 0,5-1% accordingly. Copper (Cu) makes up the remaining part (approximately 64.4-70%).
Advantages / disadvantages
Advantages:
it has high resistance to corrosion in some environments;
it has acceptable strength characteristics;
it has good technological properties - plasticity and weldability;
it has an attractive appearance.
Disadvantages:
this material is quite expensive compared to other corrosion-resistant materials.
Cupronickel application areas
The main practical useful property is high corrosion resistance in fresh and sea water. This makes it possible to use cupronickel as a structural material for the production of ship parts, heat exchangers, and pipeline fittings. Also, various medical instruments are made from this material. Cupronickel is also widely used in the production of coins, jewelry and tableware creation. For these purposes, as a rule, the grade MN25 with a nickel content of 24-26% is used.
Cupronickel products
The main product types that the industry produces are cupronickel rods and round bars, cupronickel rods, cupronickel rods and flat bar. All of these products are used in areas where there are high requirements to the corrosion resistance of materials, and to the appearance of products.