70% nickel, 30% iron
Balco has been used in thermometer bulbs and other applications that require high temperature coefficient of resistance. It has a temperature coefficient similar to nickel and twice the resistivity. The slope of the temperature resistance curve is almost straight from -70° to 600° C (-94° to 1,112° F). Balco conforms to the ASTM specification B-267, Class 8 Alloy.
Factors for determining resistance at various temperatures
| Temperature Deg. C | 20 | 100 | 200 | 300 | 400 | 500 | 600 | 700 |
|---|---|---|---|---|---|---|---|---|
| Temperature Deg. F | 68 | 212 | 392 | 572 | 752 | 932 | 1112 | 1292 |
| Factor | 1 | 1.4 | 1.97 | 2.65 | 3.33 | 3.93 | 4.48 | 4.98 |
*Balco is a registered trademark of Carpenter Technology Corporation.
Other properties
- Resistivity, ohms/cmf: 120
- Specific Gravity: 8.46
- Temperature Coefficient of resistance
- ohms/ohm/Deg. (20°-100°C) +.0043
- ohms/ohm/Deg. (25°-100°C) +.0045
- Coefficient of linear expansion
- in./in./Deg. (20°-100°C): 15.0 x (10)-6
- Density (lbs/cubic in.): 0.305
- Magnetic Attraction: Strong
- Melting Point (approximate): 1,425°C (2,600°F)
Resistivity = 120 Ohms per circular mil foot at 20° C (68° F)
Weight = .305 lbs per cubic inch