resistance wire - wikipedia, the free encyclopedia

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Resistance wireFrom Wikipedia, the free encyclopedia

Resistance wire is wire intended for making electrical resistors.[1] It is desirable that the chosen alloy have high

resistivity, as a shorter wire can then be used. In many situations the stability of the resistor is of primary

importance, and thus the alloy's temperature coefficient of resistivity and corrosion resistance.

When resistance wire is used for heating elements (in electric heaters, toasters, and the like), high restivity and

oxidation resistance is important.

Sometimes resistance wire is insulated by ceramic powder and sheathed in a tube of another alloy; such heating

elements are used in electric ovens and water heaters and in specialized forms for cooktops.

Types

Nichrome, a non-magnetic 80/20 alloy of nickel and chromium, is the most common resistance wire for heating

purposes because it has a high resistivity and resistance to oxidation at high temperatures. When used as a

heating element, resistance wire is usually wound into coils. One difficulty in using nichrome wire is thatcommon tin-based electrical solder will not stick to it, so the connections to the electrical power must be made

using other methods such as crimp connectors or screw terminals.

Kanthal (Alloy 875/815), a family of iron-chromium-aluminium (FeCrAl) alloys used in a wide range of

high-temperature applications.

Constantan [Cu55Ni45] has a low temperature coefficient of resistivity and as a copper alloy, is easily soldered.

Other constant-resistance alloys include manganin [Cu86Mn12Ni2], Cupron [Cu53Ni44Mn3][2] and Evanohm.

The Evanohm family of nickel-chrome alloys [Ni72Cr20Mn4Al3Si1],[3] [Ni73Cr20Cu2Al2Mn1Si],[4] have high

resistance, low temperature coefficient of resistance, low electromotive force (Galvani potential) when incontact with copper, high tensile strength, and also are very stable with regards to heat treatment.

Balco [Ni70Fe30] and similar alloys have very high, but more linear, temperature coefficient of resistivity,

making them suitable for sensing elements.

Many elements and alloys have been used as resistance wire for special purposes. The table below lists the

resistivity of some common materials. The resistivity of amorphous carbon actually has a range of 3.8 - 4.1 ×

10-6 Ω m.

tance wire - Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Resista

12/14/2015



Material Resistivity

(ohm-cmil/ft)

Resistivity

(10-6 ohm-cm)

Aluminum 15.94 2.650

Brass 42.1 7.0

Carbon (amorphous) 23 3.95

Constantan 272.97 45.38

Copper 10.09 1.678

Iron 57.81 9.61

Manganin 290 48.21

Molybdenum 32.12 5.34

Nichrome 675 112.2

Nichrome V 650 108.1

Nickel 41.69 6.93

Platinum 63.16 10.5

Stainless steel (304) 541 90

Steel (0.5% carbon) 100 16.62

Zinc 35.49 5.90

Common Alloy Trade Names

[5]

MWS Wire Ind. Carpenter Tech. Driver-Harris Harrison Hoskins Jelliff KanthalMWS-875 Alchrome 875 HAI-FeCr AI 25 Alloy 875 Kanthal A-1

MWS-800 Evanohm Karma HAI-431 Chromel R Alloy 800 Nikrothal L

MWS-675 Tophet C Nichrome HAI-NiCr 60 Chromel C Alloy C Nikrothal 6

MWS-650 Tophet A Nichrome V HAI-NiCr 80 Chromel A Alloy A Nikrothal 8

MWS-294 Cupron Advance HAI-CuNi 102 Copel Alloy 45 Cuprothal 294

MWS-180 180 Alloy Midohm HAI-180 Alloy 380 Alloy 180 Cuprothal 180

MWS-120 Balco Hytemco HAI-380 Alloy 120

MWS-90 90 Alloy #95 Alloy HAI-90 Alloy 290 Alloy 90 Cuprothal 90MWS-60 60 Alloy Lohm HAI-60 Alloy 260 Alloy 60 Cuprothal 60

MWS-30 30 Alloy #30 Alloy HAI-30 Alloy 230 Alloy 30 Cuprothal 30

References

http://www.pelicanwire.com/products/resistance-wire/1.

https://www.cartech.com/ssalloysprod.aspx?id=1940 Carpenter Technology, CBX Cupron® Alloy2.

http://cartech.ides.com/datasheet.aspx?I=101&TAB=DV_DS&E=26 Carpenter Technology, Evanohm Alloy S3.


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http://cartech.ides.com/datasheet.aspx?I=101&TAB=DV_DS&E=27 Carpenter Technology, Evanohm Alloy R 4.

http://www.pelicanwire.com/products/resistance-wire/5.

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resistance wire - wikipedia, the free encyclopedia

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