Copper Nickel Fasteners

Copper Nickel Fasteners are an ideal mixture of copper and nickel with additions of manganese and ferrous contents like iron which when combined together fight seawater corrosion. Cupro nickel fasteners and copper nickel fasteners are the most common trade names used in the fastener industry. It is used in marine seawater applications show excessive resistance towards corrosions and are often used for its unique feature of thermal stability.
Copper Nickel Fasteners are available in two variations viz 70-30 (C70600) and 90-10( C71500 ) .C70600 Copper nickel is stronger as of the two with a yield strength of 150 Mpa in annealed condition as compared to 120 Mpa of C75100 Copper Nickel. Especially in case of cupro nickel 70-30 bolts as compared to copper nickel 70-10 bolts where tensile is the deciding factor due to high level of corrosion in marine applications. Torqbolt is a well known Copper Nickel Fasteners supplier in India.

Copper Nickel Alloys are well known worldwide with different trade names and unique numbers. Following chart shows the exact equivalent designations corresponding to the cross reference of copper nickel alloys.

Alloy UNS No. British Standard En name Werkstoff No.
CuNi 70/30 C71500 2871 CuNi30Fe 2.0882
CuNi 90/10 C70600 2871 CuNi10Fe 2.0872

Cupro nickel 90-10 consists of 90% copper and 10% nickel , which is less durable as compared to 70-30 alloys. This alloy is cheaper and easily available.

Copper Nickel 90-10 Cu Fe Pb Mn Ni Zn
Min/max Rem 1.0-1.8 0.05 1.00 9.0-11.0 1.00
Nominal 88.60 1.40 10.0

Notes: (1)Cu value includes Ag.
(2)Ni value includes Co.
(3)Cu + Sum of Named Elements, 99.5% min.

Alloy Yield strength Tensile strength Elongation
Min 0.2% Mpa Min Mpa Min %
Cupronickel 90-10 110-393 303-414 42
Alloy Density Elastic Modulus Mean Coefficient of Thermal Thermal Conductivity Specific Heat
(Kg/m3) (Gpa) Expansion(μm/m/°C) (W/m.K) 0-100°C
Cupronickel 90-10 8.94 140 17.1 45 377
CuproNickel 70-30 is a well-known alloy as compared to cupro nickel 90-10, with higher additions of nickel as compared to the lower alloy.

It has 70% copper and 30% nickel with a higher toughness and strength at hardened stages, Widely used due to superior properties.

Copper Nickel 70-30 Cu Fe Pb Mn Ni Zn
Min/max Rem 0.4-1.0 0.05 1.00 29.0-33.0 1.00
Nominal 69.50 0.50 30.0

Notes: (1)Cu value includes Ag.
(2)Ni value includes Co.
(3)Cu + Sum of Named Elements, 99.5% min.

Alloy Yeild strength Tensile strength Elongation
Min 0.2% Mpa Min Mpa Min %
Cupronickel 70-30 88.0-483 372-517 45
Alloy Density Elastic Modulus Mean Coefficient of Thermal Thermal Conductivity Melting Point
(Kg/m3) (Gpa) Expansion(μm/m/°C) (W/m.K) (nΩ.m)
Cupronickel 70-30 8.94 117 16.2 29 1171

Marine Usage
Due to excellent resistance towards marine water corrosion, more than 90% it used in the marine industry with attachments of copper nickel flanges, pipes and fittings. Salt water flanged connections are very well protected with copper nickel bolts set with cupro nickel nut and washers. Propeller shafts, distiller tubes, ferrule fittings all are attached with cupro nickel screws with nuts as a pair.

Automotive Use
Copper nickel bolts are quite famous for automotive components like the steering tube and brake lines.
Fabrication
Copper Nickel Studs used for pressure vessels, heat exchangers, condenser plates, valve bodies and evaporators are very much in demand.

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