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Copper Nickel Alloy Wire Heating

Cupronickel (also known as copper-nickel) is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. Despite its high copper content, cupronickel is silver in colour. Due to the specific properties of nickel and copper alloys, they are applied in various domains of industry e.g. mint industry, armaments industry, desalination industry, marine engineering, extensively used in the chemical, petrochemical and electrical industries. Cupronickel is highly resistant to corrosion in seawater because its electrode potential is adjusted to be neutral with regard to seawater. For this reason, it is used for piping, heat exchangers and condensers in seawater systems, marine hardware, and sometimes for the propellers, crankshafts and hulls of premium tugboats, fishing boats and other working boats. Another common use of cupronickel is in silver-coloured modern-circulated coins. A typical mix is 75% copper, 25% nickel, and a trace amount of manganese. In the past, true silver coins were debased with cupronickel. Single-core thermocouple cables use a single conductor pair of thermocouple conductors such as iron-constantan, copper constantan or nickel-chromium/nickel-aluminium. These have the heating element of constantan or nickel-chromium alloy within a sheath of copper, cupronickel or stainless steel.

Copper Nickel Resistance Alloys

Copper Nickel (CuNi) alloys are medium to low resistance materials typically used in applications with maximum operating temperatures up to 600°C (1,110°F).

With low temperature coefficients of electrical resistance, resistance, and thus performance, is consistent regardless of temperature. Copper Nickel alloys mechanically boast good ductility, are easily soldered and welded, as well as have outstanding corrosion resistance. These alloys are typically used in high current applications requiring a high level of precision.

Copper Nickel Alloy Wires for the manufacturing of low temperatures electric resistances so as heating principally destined cables, shunts, resistances for automobile, they have a maximum operating temperature of 400 C. They do not therefore intervene in the field of resistances for industrial furnaces. The most known, CuNi 44 (also called Constantan) presents the advantage of a very low temperature coefficient.

There are also CuMnNI alloys of chemical composition copper and nickel with addition of manganese with a low resistivity (from 0.49 to 0.05 Ohm mm/m).

Common Name: Alloy 294, Alloy 49, Cu-Ni 44
Motor control, heating wires and cables; precision and vitreous resistors, potentiometers.
Datasheet

Common Name: Alloy 30, Cu-Ni 23, Cu-Ni 23, Alloy 260
Alloy exhibits low resistivity and high temperature coefficient of resistance. Typical applications include voltage regulators, timing devices, temperature sensitive resistors, temperature compensating devices, motor control, heating wires and cables, precision and vitreous resistors, potentiometers, and low temperature heating applications.
Datasheet

Common Name: Alloy 95, 90 Alloy, Cu-Ni 10, Cu-Ni 10, Alloy 320
Alloy exhibits low resistivity and high temperature coefficient of resistance. Typical applications include voltage regulators, timing devices, temperature sensitive resistors, temperature compensating devices, motor control, heating wires and cables, precision and vitreous resistors, potentiometers, and low temperature heating applications.
Datasheet

Common Name: Alloy 180, 180 Alloy, Cu-Ni 23, Nickel Alloy 180
Alloy exhibits low resistivity and high temperature coefficient of resistance. Typical applications include voltage regulators, timing devices, temperature sensitive resistors, temperature compensating devices, motor control, heating wires and cables, precision and vitreous resistors, potentiometers, and low temperature heating applications.
Datasheet

Copper Nickel Resistance Heating Wire

Copper Nickel Resistance Heating Wire are principally destined for the manufacturing of low temperatures electric resistances so as heating cables, shunts, resistances for automobile, they have a maximum operating temperature of 752F. They do not therefore intervene in the field of resistances for industrial furnaces. Those are alloys of chemical composition copper + nickel with addition of manganese with a low resistivity (from 231.5 to 23.6 Ohm.mm2/ft). The most known, CuNi 44 (also called Constantan) presents the advantage of a very low temperature coefficient.

Their advantages are the following:

Copper–manganese alloys (~84% Cu, 12% Mn with nickel, aluminium or germanium as the remaining constituent). These Cu-Mn-Ni alloys are sold under various proprietary names, and manganin, the pioneer alloy of this group, was for many years the traditional material for high-grade standard resistors. The resistivity is about 40 × 10−8 Ω m and varies approximately parabolically with temperature over the range 0 to 50 °C, with a maximum close to 20 °C. The temperature coefficient can be as low as 3 × 10−6 °C−1 over the range 15 °C to 20 °C. Its secular stability is very good and, if wires are supported in strain-free conditions, can be less than 1 in 107 per year. The thermo-e.m.f. of the alloys against copper is close to zero and may be positive or negative according to composition and heat treatment. Joints between the copper manganese alloys and copper are made most effectively by welding in an atmosphere of argon, and by hard soldering if welding is impracticable.

Copper–nickel alloys (~55% Cu, 45% Ni). These alloys are manufactured commercially under a wide range of proprietary names, and are used in the construction of standard resistors. The resistivity is about 50 × 10−8 Ω m with a temperature coefficient which may lie between ±0.000 04 °C−1. The alloys can be soft-soldered with ease, but their high thermo-e.m.f. against copper (~40 μV °C−1) is a disadvantage in d.c. resistors, although the effect is usually negligible in a.c. resistors dropping 1 volt or more. These alloys are also used for current controlling resistors when constancy is more important than low cost.

Copper-nickel alloy is designed for specialized electrical and electronic applications. It has a very low temperature coefficient of resistance and medium-range electrical resistivity. Used for wire-wound precision resistors and bimetal contacts which change on heating by electrical resistance.

Copper Nickel Low Resistance Alloy is used in Heat Exchangers and Condensers. Good thermal conductivity and corrosion resistance to the sea water flow rates required have allowed copper-nickel tubing to remain an established alloy where high reliability is called for. A copper-nickel alloy of the 70-30 type having superior weldability. It is resistant to corrosion and biofouling in seawater, has good fatigue strength, and has relatively high thermal conductivity. Used for seawater condensers, condenser plates, distiller tubes, evaporator and heat exchanger tubes, and saltwater piping.

Copper Nickel Alloy Properties

Copper-Nickel Foil For Heating Elements

Cu-Ni Foil is an extremely good combination property that is used in the largest amount and most widely as a corrosion resistance alloy. This alloy in hydrofluoric acid and fluoride gas medium with excellent corrosion resistance, as well as to the hot concentrated alkali. At the same time, it is corrosion resistant to neutral solution, sea water, air, organic compounds. An important feature of this copper nickel alloy is generally not to generate stress corrosion cracking and have good cutting performance. Cu-Ni Foil alloy is high-intensity single-phase solid solution.

Cu - Ni Foil alloy in fluoride gas, hydrochloric acid, sulfuric acid, hydrofluoric acid and their derivatives have a very good corrosion resistance property, and possess better corrosion resistance more than copper alloy in the sea water. Acid medium: Cu-Ni Alloy Foil have corrosion resistance in less than 85% consistency of sulfuric acid. Cu-Ni Foil alloy is an important material that resistant to hydrofluoric acid. Water corrosion: Cu-Ni Foil alloy in most corrosion cases of water, not only excellent corrosion resistance, but also less pitting, stress corrosion, the corrosion rate less than 0.025mm. High temperature corrosion: Cu-Ni Alloy Foil for the work of the highest temperature at about 600 °C in general in the air, in the high temperature steam, the corrosion rate less than 0.026mm. Ammonia: Cu-Ni Alloy Foil can be resistant to an hydrous ammonia and aminate conditions corrosion below 585 °C due to the high nickel.

Cu-Ni Foil copper nickel alloy is a multi-purpose material in many industrial applications: 

  1. Seamless water pipe in the power factory
  2. Sea-water exchanger and evaporator
  3. Sulfuric acid and hydrochloric acid environment
  4. Crude distillation
  5. Sea-water in the use of equipment and propeller shaft
  6. Nuclear industry and used in the manufacture of uranium enrichment isotope separation equipmen
  7. Manufacturing hydrochloric acid equipment used in the production of pump and valve. 

Heater utilizing copper-nickel alloy

An electrical resistance heater which utilizes a copper-nickel alloy heating cable. This metallurgy heating cable is significantly less prone to failure due to localized overheating because the alloy has a low temperature coefficient of resistance. Used as a well heater, the heating cable permits heating of long segments of subterranean earth formation with a power supply of 400 to 1200 volts.

Copper Nickel Electrical low resistance heaters suitable for heating long intervals of subterranean earth formations have been under development for many years. These heaters have been found to be useful for carbonizing hydrocarboncontaining zones for use as electrodes within reservoir formations, for enhanced oil recovery and for recovery of hydrocarbons from oil shales. One process is to create electrodes utilizing a subterranean heater. The heater utilized is capable of heating an interval of 20 to 30 meters within subterranean oil shales to temperatures of 500°C. to 1000°C. Iron or chromium alloy resistors are utilized as the core heating element. These heating elements have a high resistance and relatively large voltage is required for the heater to extend over a long interval with a reasonable heat flux. It would be preferable to utilize lower resistance material. Further, it would be preferable to use a material which is malleable to permit more economical fabrication of the heater.

Subterranean heaters having copper core heating elements are disclosed. This core has a low resistance, which permits heating long intervals of subterranean earth with a reasonable voltage across the elements. Further, because copper is a malleable material, this heater is much more economical to fabricate. These heaters can heat 1000-foot intervals of earth formations to temperatures of 600° C. to 1000° C. with 100 to 200 watts per foot of heating capacity with a 1200 volt power source. But copper also has shortcomings as a material for a heating element. As the temperature of a copper heating element increases, the electrical resistance increases at a rate which is undesirably high. If a segment of the heating coil becomes excessively hot, the increase in electrical resistance of the hot segment causes a cascading effect which can result in failure of the element.

A subterranean heater utilizing an electric resistant heater element having a lower temperature coefficient of resistance would not only improve temperature stability, but would simplify the power supply circuitry. It is therefore the object to provide an improved heater capable of heating long intervals of subterranean earth wherein the heating element has a low temperature coefficient of resistance, a low electrical resistance, and utilizes a core of a malleable metal material.

When this copper-nickel alloy is incorporated into such a heater cable the benefits of a low resistance heater are obtained along with the benefit of having a low temperature coefficient of resistance. The heater cable material is also malleable. Such a heater can therefore be utilized to heat subterranean intervals of earth to temperatures of 500° C. to 1000° C. utilizing voltages in the range of 400 to 1000 Volts.

These copper nickel alloy heater coils are less likely to fail prematurely because the resistance of the cable in hot segments is much nearer to the resistance of the remaining coil. Hot spots therefore have less tendency to continue to increase in temperature due to higher electrical resistance, causing premature failure. The electrical resistance of the copper nickel alloy element also varies less between the initial cool state and the service temperatures which simplifies the power supply circuitry. The benefits of the low resistance and low temperature coefficient of resistance copper nickel alloy heater element are most significant when the heater is one which applies heat over large intervals of subterranean earth and at a temperature level of 600° C. to 1000° C. lntervals of 1000 feet or more can be heated with these heaters.