Nichrome belongs to the class of precision alloys with high electrical resistance, which determines its use as electric heaters. The page contains a description of this material: physical properties, application area, brands, types of products.
Basic information
Nichrome is an alloy consisting of the following elements: Ni (55-78%); Cr (15-23%); Mn (1.5%); the rest is Fe. Resistivity - 1,0-1,1·10-6 Ω·m, density - 8200-8500 kg/m3, melting point - 1100-1400 °C. The material has a high operating temperature (up to 1100 °C) and mechanical strength (tensile strength - 0.65-0.70 GPA).
This alloy of chromium and nickel is used for the production of heating elements for laboratory and industrial electric furnaces, stoves, soldering irons.
History
The first nichrome alloy was developed by staff of the American Driver-Harris Company in the United States in 1905.
Nichrome properties
Property
Grades
NiCr 80 20
NiCr 60 15
Density, g/cm3
8,4
8,2
Melting point, °С
1400
1390
Resistivity, Ω·m
1,0-1,1·10-6
Magnetic field
nonmagnetic
nonmagnetic
Hardness, НВ
140-150
140-150
Specific heat, kJ / kg · K at 25°C
0,44
0,46
Nichrome grades
The most common grades in the industry are Ni80Cr20, Ni60Cr15. After the letter Cr comes the percentage of chromium, after the letter Ni - of nickel. There are also grades with extra additives. Ni80Cr20-N, Ni60Cr15-N contain zirconium as an additive. Except the additives, the grade may contain information about the method of the alloy production. Ni60Cr15-VI and Ni80Cr20-VI are made by vacuum-induction melting.
it is easy to process, as it has good plasticity and weldability;
it is creep resistant (creep resistance - is resistance of a material to inelastic deformation arising at a temperature above 400°C under the action of high pressure);
It is nonmagnetic.
Disadvantages:
it has a high cost;
the maximum operating temperature is lower than some other alloys with high electrical resistance have.
Nichrome application area
Nichrome is used in electric heaters of furnaces for all industries, household appliances and devices of thermal action. It is widely used in high-temperature electric furnaces, kilns and dryers, various electric devices of thermal action. It serves as heating and resistor elements. It has high heat resistance, creep resistance, plasticity and shape stability. Also, this material is used as a heat-resistant (heat-stable) and chemically resistant alloy in certain aggressive environment.
In particular, nichrome Ni80Cr20 is the material for heating elements of industrial electric furnaces and various electric heating devices. It is recommended to use for electrothermal equipment heaters of high reliability.
Nichrome Ni60Cr15 is used for production of the same products as Ni80Cr20, and is also used in electronic products and for creation of non-precision resistors.
Products from nichrome
The industry produces next main types of products: nichrome wire, filament (small diameter wire) and strip. In some cases rods and round bars are produced. All these products are used for production of round and flat heaters for electric furnaces.