1. Introduction
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 that common tin-based electrical solder will not bond with it, so the connections to the electrical power must be made using other methods such as crimp connectors or screw terminals.
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]and Evanohm.
The Evanohm family of nickel-chrome alloys [Ni72Cr20Mn4Al3Si1], [Ni73Cr20Cu2Al2Mn1Si], have high resistance, low temperature coefficient of resistance, low electromotive force (Galvani potential) when in contact with copper, high tensile strength, and also are very stable with regards to heat treatment.
2.Specification:
| Grade | Main chemical composition | Hightest temperature ℃ | Rrsistivity µΩ.m | Melting point ℃ | Tensile strength N/mm² | Elogation % | Working life h/℃ | Magnetic properties |
| | Cr | Al | Ni | Fe | | | | | | | |
| OCr21Al4 | 17-21 | 3-4 | - | - | 1100 | 1.23±0.06 | 1500 | 750 | ≥12 | ≥80/1250 | magnetic |
| OCr25Al5 | 23-26 | 4.5-6.5 | - | - | 1250 | 1.42±0.07 | 1500 | 750 | ≥12 | ≥80/1300 | magnetic |
| OCr21Al6Nb | 21-23 | 5-7 | - | - | 1350 | 1.43±0.07 | 1510 | 750 | ≥12 | ≥50/1350 | magnetic |
| OCr27Al7Mo2 | 22-24 | 5-7 | - | - | 1400 | 1.53±0.07 | 1520 | 750 | ≥10 | ≥50/1350 | magnetic |
| KSC | 26.8-27.8 | 6-7 | - | - | 1350 | 1.44±0.05 | 1510 | 750 | ≥16 | ≥60/1350 | magnetic |
| Cr20Ni80 | 20-23 | - | Rest | ≤1.0 | 1200 | 1.09±0.05 | 1400 | 750 | ≥20 | ≥80/1200 | Non-magnetic |
| Cr30Ni70 | 30 | - | Rest | ≤1.0 | 1250 | 1.18±0.05 | 1380 | 750 | ≥20 | ≥50/1250 | Non-magnetic |
| Cr15Ni60 | 15-18 | - | 55 | Rest | 1150 | 1.12±0.05 | 1390 | 750 | ≥20 | ≥80/1150 | Non-magnetic |
| Cr20Ni35 | 18-21 | - | 35 | Rest | 1100 | 1.04±0.05 | 1390 | 750 | ≥20 | ≥80/1100 | Weak magnetic |
| Cr20Ni30 | 20 | - | 32 | Rest | 1100 | 1.04±0.05 | 1390 | 750 | ≥20 | ≥80/1100 | Weak magnetic |
3.
| 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 |
