Nichrome is peculiar with its high resistance that determines the application of the products made of this alloy. Nichrome wire and filament seem to be the most highly-demanded semifinished materials. They are used in
electrical furnace heaters, electrical equipment, e-cigarettes, medical supplies.
Nichrome wire and filament are sold at Metotechnics. Customers can order NiCr 80 20, NiCr 60 15 and other grades in different ways (via phone, fax, e-mail, on website).
More details on the materials so as on ways of production and application of the described products can be found here in corresponding sections. Standards provided on the website are also very informative.
Grades
Nichrome (also called as NiCr alloy, nickel-chromium alloy or chromium-nickel alloy) is a heat-resisting alloy with high resistance, low thermal resistance constant, strong air and gas corrosion resistance under high temperatures. Also it has good handling properties (cold ductility, fusability); nichrome can be used for producing nichrome wire, filament, band, strip, rods and other semifinished materials; it is highly heat-resisting, sustains mechanical load without strong deformation and does not fail under high temperatures. Heat-resisting oxides form a highly-dense coating on the surface of these alloys. These two factors provide the high heat resistance of this precision material.
NiCr 80 20 (or Ni80Cr20, Cr20Ni80 and Nikrothal® 80) and NiCr 60 15 (or Ni60Cr15, Cr15Ni60 and Nikrothal® 60) grades are the most common ones. Also NiCr 80 20 Zr, NiCr 80 20-VI, NiCr 60 15 Zr and NiCr 60 15 VI
nichrome grades are used.
The marking of these alloys stands for the following: the letter means the chemical element and the number that follows it is the average mass % of such element in the alloy. E.g., NiCr 80 20 nichrome contains 20-23% of
chrome (Cr) and about 80% of
nickel (Ni), NiCr 60 15 nichrome contains 15-18% of chrome (Cr) and about 60% of nickel (Ni). Letters VI in the end of the grade name mean that this material was produced by a special method (that is vacuum-induction melting). Letter Н in the end of the grade name means that it contains zirconium that makes the nichrome heater more reliable due to increased resistance under the highest working temperature.
The chemical composition of NiCr 80 20, NiCr 80 20 Zr, NiCr 80 20 VI и NiCr 60 15, NiCr 60 15 Zr and NiCr 60 15 VI grades is governed by GOST 10994-74 standard.
Production
Nichrome wire is produced by chipless shaping, that is fullering process. This is made without additional heating of blanks, so the product is cold-drawn.
Nichrome wire is supplied in soft state due to annealing. In some cases, the surface is pickled. Mechanical processing including turning, grinding and other operations is not performed due to small size of the blanks.
Product sizes, mechanical properties, supply state, resistance and maximum working temperatures are regulated by ГОСТ 12766.1-90 and ГОСТ 8803-89 standards.
It should be mentioned that the round-section semifinished material with a small diameter is called nichrome filament. Such semifinished material is not described in the standards, but this term is rather common among experts.
Application
The group of the material determines its application. Nichrome is a precision alloy with a high resistance. Nichrome wire and filament are mainly used for production of round heaters for electrical furnaces. Nichrome filament is used in low-power furnaces and nichrome wire is used for more powerful furnaces. Non-insulated products are suitable for this. However, some applications require an electrical heater with a relatively low temperature (e.g., car seat heating). Here
insulated nichrome is used. This allows embedding the heater into the seat padding and provide the use safety.
Also nichrome wire is applied for production of resistive elements used in various electrical appliances.
GOST 12766.1-90 classifies the products by their application:
- NiCr 80 20 Zr, NiCr 60 15 Zr grade alloys:
- for heaters;
- for electric heater tubes;
- NiCr 60 15 grade alloys:
Resistance of NiCr 80 20 nichrome wire
It is one of the most important alloy property. It is determined by many factors. In particular, nichrome resistance depends on the product size and grade.
The general formula is written as:
R = ρ · l / S,
where
R - is real resistance (Ohm),
ρ is specific resistance (Ohm·mm),
l is conductor length (mm),
S is sectional area (mm
2).
Resistance values for 1 m of product. NiCr 80 20 nichrome wire
D, мм |
R (theoretical), Ohm |
Ø 0,1 |
137,00 |
Ø 0,2 |
34,60 |
Ø 0,3 |
15,71 |
Ø 0,4 |
8,75 |
Ø 0,5 |
5,60 |
Ø 0,6 |
3,93 |
Ø 0,7 |
2,89 |
Ø 0,8 |
2,20 |
Ø 0,9 |
1,70 |
Ø 1,0 |
1,40 |
Ø 2,0 |
0,35 |
Ø 3,0 |
0,16 |
Ø 4,0 |
0,087 |
Ø 5,0 |
0,056 |
Ø 6,0 |
0,039 |
Ø 7,0 |
0,029 |
Ø 8,0 |
0,022 |
Ø 9,0 |
0,017 |
Ø 10,0 |
0,014 |
Nichrome filament is applied in medicine as a stitch material. Also these products are used for producing wires for shape cutting of foam and other similar materials.
Prices
See the product range and prices of the nichrome wire on the
Cost page. Products can be ordered on the same page by filling in a special form.