6J40 Constantan Copper-Nickel Alloy Optimal Choice For Stable Electrical Properties
6J40 Constantan Copper-Nickel Alloy The Optimal Choice for Stable Electrical Properties
A constant alloy is a type of metal alloy designed to maintain stable and consistent properties, particularly electrical resistance, over a wide range of temperatures. The most well-known constant alloy is Constantan, a copper-nickel alloy that is widely used in temperature sensors (thermocouples), resistors, and heating elements due to its stable electrical and thermal characteristics.
Constant alloys, like 6J40, are valued for their reliable and consistent performance in a wide range of applications. Their ability to maintain stable electrical resistance and durability under varying environmental conditions makes them essential in industries like electronics, manufacturing, and scientific instrumentation.
Chemical composition
| Name | Code | Main Composition(%) | Density | |||
| Cu | Mn | Ni | Cr | g/mm2 | ||
| Constantan | 6J40 | Bal. | 1~2 | 39~41 | -- | 8.9 |
Properties
| Name | Code | Resistivity(20℃)(μΩm) | Temp.Coeff.Of Resistance (20℃)(α×10-6/℃) | (0~100℃) Thermal EMF vs. Copper (μv/℃) | Max. Working Temp. (℃) | Elongation(%) | Tensile Strength(N/mm2) |
| Constantan | 6J40 | 0.48±0.03 | -40~+40 | 45 | ≤500 | ≥15 | ≥390 |
Diameter and Tolerance
| Diameter | 0.02~0.028 | 0.032~0.10 | 0.112~0.28 | 0.315~0.50 | 0.56~1.0 | 1.06~1.60 | 1.70~2.12 | 2.24~3.00 | 3.15~4.50 |
| Tolerance | ±0.002 | ±0.003 | ±0.005 | ±0.010 | ±0.015 | ±0.020 | ±0.025 | ±0.030 | ±0.035 |
Some key features of 6J40 include:
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Stable Electrical Resistance:
- Constantan (commonly an alloy of 55% copper and 45% nickel) maintains constant electrical resistance across a wide range of temperatures. This property makes it particularly useful in applications requiring precise and stable resistance, such as in thermocouples (temperature sensors) and resistors.
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2. Low Temperature Coefficient of Resistance:
- The alloy's resistance does not change much with temperature fluctuations. This low temperature coefficient ensures that devices made from constant alloys will maintain stable performance even in environments with varying temperatures.
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3. Good Corrosion Resistance:
- Constant alloys, especially Constantan, have good corrosion resistance, making them durable for long-term use in harsh environments. This is essential in outdoor and industrial applications where exposure to moisture, chemicals, or high humidity is common.
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4. Thermoelectric Properties:
- Due to its stable electrical resistance, Constantan is widely used in thermocouples to measure temperature. The difference in voltage generated by two different metals (like Constantan and another metal) when exposed to heat is used in these sensors to provide accurate temperature readings.
- Thermoelectric Seebeck Coefficient: Constantan has a good Seebeck coefficient, which means it can generate a voltage that is proportional to the temperature difference across the metal, making it ideal for temperature measurement.
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5. Durability and Strength:
- Constant alloys are relatively strong and resistant to mechanical wear. Their tensile strength and mechanical stability make them useful in applications that require durability, such as in electrical cables, resistance wire, and heating elements.
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6. Formability and Ductility:
- Constant alloys are generally ductile and can be easily drawn into thin wires or formed into various shapes without losing their properties. This makes them versatile for use in a wide variety of applications, from precision resistors to wire-wound heating elements.
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7. High Melting Point:
- Constant alloys typically have high melting points, allowing them to withstand high temperatures without degradation. This property is especially useful in heating elements (like those in ovens, toasters, and industrial furnaces) that require stable performance under heat stress.
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8. Magnetic Properties:
- Constantan and similar alloys typically have non-magnetic properties, which makes them useful in applications where magnetic interference needs to be avoided, such as in sensitive electronic equipment or instrumentation.
Applications:
- Thermocouples: Constant alloys are commonly used in temperature measurement devices due to their stable resistance.
- Electrical Resistance: Used in resistors, shunt resistors, and strain gauges due to their predictable and stable resistance characteristics.
- Heating Elements: Used in high-temperature resistance wires for electric heating applications.
- Sensors and Instrumentation: Due to their stable resistance, constant alloys are used in pressure sensors, strain gauges, and other precision instruments.
Constantan (6J40) Technical data of wires
| Dia(m) | Cross-sectional area(m²) | Weight/m (g/m) | Resistance/m at 20℃(Ω/m) | Dia(m) | Cross-sectional area(m²) | Weight/m (g/m) | Resistance/m at 20℃(Ω/m) |
| 0.020 | 0.000314 | 0.00279 | 1375-1681 | 0.224 | 0.03941 | 0.350 | 11.4-12.9 |
| 0.022 | 0.000318 | 0.00337 | 1136-1389 | 0.250 | 0.04909 | 0.436 | 9.19-10.37 |
| 0.025 | 0.000491 | 0.00434 | 880-1076 | 0.280 | 0.06158 | 0.5468 | 7.33-8.26 |
| 0.028 | 0.000616 | 0.00547 | 702-857 | 0.315 | 0.07793 | 0.6920 | 5.85-6.47 |
| 0.032 | 0.000804 | 0.00714 | 549-645 | 0.355 | 0.09898 | 0.8789 | 4.61-5.09 |
| 0.036 | 0.001018 | 0.00904 | 434-509 | 0.400 | 0.12570 | 1.116 | 3.63-4.01 |
| 0.040 | 0.001257 | 0.01116 | 351-413 | 0.450 | 0.15900 | 1.412 | 2.87-3.17 |
| 0.045 | 0.001509 | 0.01412 | 278-326 | 0.500 | 0.19630 | 1.744 | 2.32-2.57 |
| 0.050 | 0.001963 | 0.01744 | 225-264 | 0.560 | 0.24630 | 2.19 | 1.87-2.03 |
| 0.056 | 0.002463 | 0.02187 | 179-210 | 0.630 | 0.31170 | 2.77 | 1.48-1.60 |
| 0.063 | 0.003117 | 0.02768 | 142-166 | 0.710 | 0.39590 | 3.52 | 1.16-1.26 |
| 0.071 | 0.003959 | 0.03516 | 112-131 | 0.750 | 0.44180 | 3.92 | 1.04-1.13 |
| 0.080 | 0.005027 | 0.04464 | 87.9-103.1 | 0.800 | 0.50270 | 4.46 | 0.917-0.993 |
| 0.090 | 0.006362 | 0.05650 | 69.4-81.5 | 0.850 | 0.56740 | 5.04 | 0.812-0.880 |
| 0.100 | 0.007854 | 0.06970 | 56.2-66.0 | 0.900 | 0.63620 | 5.65 | 0.724-0.785 |
| 0.112 | 0.009852 | 0.08749 | 45.3-52.1 | 0.950 | 0.70880 | 6.29 | 0.650-0.704 |
| 0.125 | 0.012270 | 0.10900 | 36.4-41.9 | 1.000 | 0.78540 | 6.97 | 0.587-0.636 |
| 0.140 | 0.015390 | 0.13670 | 29.0-33.4 | 1.060 | 0.88250 | 7.84 | 0.522-0.566 |
| 0.150 | 0.017670 | 0.15690 | 25.3-29.1 | 1.120 | 0.98520 | 8.75 | 0.468-0.507 |
| 0.160 | 0.020110 | 0.17850 | 22.2-25.5 | 1.180 | 1.09400 | 9.71 | 0.421-0.456 |
| 0.170 | 0.022700 | 0.20160 | 19.7-22.6 | 1.250 | 1.22700 | 10.9 | 0.375-0.407 |
| 0.180 | 0.025450 | 0.22600 | 17.5-20.2 | 1.320 | 1.36800 | 12.15 | 0.337-0.365 |
| 0.190 | 0.028350 | 0.25200 | 15.7-18.1 | 1.400 | 1.53900 | 13.67 | 0.299-0.324 |
| 0.200 | 0.031420 | 0.27900 | 14.4-16.2 | 1.500 | 1.76700 | 15.69 | 0.261-0.282 |
| 0.212 | 0.035300 | 0.31350 | 12.8-14.4 | 1.600 | 2.01100 | 17.86 | 0.229-0.248 |
Constantan strip resistance value (Ω/m)
| Width Thickness |
6.3 | 8.0 | 10.0 | 12.5 | 16.0 | 20.0 | 25.0 | 31.5 | 40.0 |
| 0.180 | 0.150 | ||||||||
| 0.200 | 0.405 | ||||||||
| 0.224 | 0.362 | 0.2850 | |||||||
| 0.250 | 0.324 | 0.2550 | 0.196 | ||||||
| 0.280 | 0.289 | 0.2280 | 0.175 | ||||||
| 0.315 | 0.257 | 0.2030 | 0.155 | 0.124 | |||||
| 0.355 | 0.228 | 0.1800 | 0.138 | 0.110 | |||||
| 0.400 | 0.203 | 0.1600 | 0.122 | 0.980 | 0.0765 | ||||
| 0.450 | 0.180 | 0.1420 | 0.109 | 0.0871 | 0.0680 | 0.0544 | 0.0435 | ||
| 0.500 | 0.162 | 0.1280 | 0.098 | 0.0784 | 0.0612 | 0.0490 | 0.0392 | ||
| 0.560 | 0.145 | 0.1140 | 0.0875 | 0.0700 | 0.0547 | 0.0437 | 0.0350 | ||
| 0.630 | 0.129 | 0.1010 | 0.0777 | 0.0622 | 0.0486 | 0.0389 | 0.0311 | ||
| 0.710 | 0.114 | 0.0900 | 0.0690 | 0.0552 | 0.0431 | 0.0345 | 0.0276 | ||
| 0.800 | 0.101 | 0.0800 | 0.0612 | 0.0490 | 0.0383 | 0.0306 | 0.0245 | 0.0194 | 0.0153 |
| 0.900 | 0.090 | 0.0710 | 0.0544 | 0.0435 | 0.0340 | 0.0272 | 0.0218 | 0.0173 | 0.0136 |
| 1.000 | 0.081 | 0.0640 | 0.0490 | 0.0392 | 0.0306 | 0.0245 | 0.0196 | 0.0155 | 0.0122 |
| 1.120 | 0.072 | 0.0570 | 0.0437 | 0.0350 | 0.0273 | 0.0219 | 0.0175 | 0.0139 | 0.0109 |
| 1.250 | 0.065 | 0.0510 | 0.0392 | 0.0313 | 0.0245 | 0.0196 | 0.0157 | 0.0124 | 0.0098 |
| 1.400 | 0.058 | 0.0460 | 0.0350 | 0.0280 | 0.0219 | 0.0175 | 0.0140 | 0.0111 | 0.0088 |
| 1.600 | 0.051 | 0.0400 | 0.0306 | 0.0245 | 0.0191 | 0.0153 | 0.0122 | 0.0097 | 0.0077 |
| 1.800 | 0.045 | 0.0350 | 0.0272 | 0.0218 | 0.0170 | 0.0136 | 0.0109 | 0.0086 | 0.00680 |
| 2.000 | 0.041 | 0.0320 | 0.0245 | 0.0196 | 0.0153 | 0.0122 | 0.0098 | 0.0078 | 0.0061 |
Constantan&Manganin wire table
| Dia.(mm) | Sectional area nominal value(mm2) | Resistance per meter (Ω/m) | ||||||||
| 6J12X | 6J8X | 6J13X | 6J40X | |||||||
| Nominal value(mm) | Tolerance | Nominal value (Ω/m) | Tolerance | Nominal value (Ω/m) | Tolerance | Nominal value (Ω/m) | Tolerance | Nominal value (Ω/m) | Tolerance | |
| 0.020 | ±0.002 | 0.000314 | 1496 | ±10% | 1528 | ±10% | ||||
| 0.022 | 0.000380 | 1236 | 1263 | |||||||
| 0.025 | 0.000491 | 957 | 978 | |||||||
| 0.028 | 0.000616 | 763 | 780 | |||||||
| 0.032 | ±0.003 | 0.000804 | 584 | ±8% | ±8% | ±8% | 597 | ±8% | ||
| 0.036 | 0.001018 | 462 | 472 | |||||||
| 0.040 | 0.001257 | 374 | 382 | |||||||
| 0.045 | 0.001590 | 296 | 302 | |||||||
| 0.050 | 0.001963 | 239 | 244 | |||||||
| 0.056 | 0.002463 | 191 | 195 | |||||||
| 0.063 | 0.003117 | 151 | 154 | |||||||
| 0.071 | 0.003959 | 119 | 121 | |||||||
| 0.080 | 0.005027 | 93.5 | 69.6 | 87.5 | 95.5 | |||||
| 0.090 | 0.006362 | 73.9 | 55.0 | 69.2 | 75.5 | |||||
| 0.100 | 0.007854 | 59.8 | 44.6 | 56.0 | 61.1 | |||||
| 0.112 | ±0.005 | 0.009852 | 47.7 | ±7% | 35.5 | ±7% | 44.7 | ±7% | 48.7 | ±7% |
| 0.125 | 0.01227 | 38.3 | 28.5 | 35.9 | 39.1 | |||||
| 0.140 | 0.01539 | 30.5 | 22.7 | 28.6 | 31.2 | |||||
| 0.160 | 0.02011 | 23.4 | 17.4 | 21.9 | 23.9 | |||||
| 0.180 | 0.02545 | 18.5 | 13.8 | 17.3 | 18.9 | |||||
| 0.200 | ±0.005 | 0.03142 | 15.0 | ±6% | 11.1 | ±6% | 14.0 | ±6% | 15.3 | ±6% |
| 0.224 | 0.03941 | 11.9 | 8.88 | 11.2 | 12.2 | |||||
| 0.250 | 0.04909 | 9.57 | 7.13 | 8.96 | 9.78 | |||||
| 0.280 | 0.06158 | 7.63 | 5.68 | 7.15 | 7.80 | |||||
| 0.315 | ±0.010 | 0.007793 | 6.03 | ±5% | 4.49 | ±5% | 5.65 | ±5% | 6.16 | ±5% |
| 0.355 | 0.09898 | 4.75 | 3.54 | 4.45 | 4.85 | |||||
| 0.400 | 0.1257 | 3.74 | 2.79 | 3.50 | 3.82 | |||||
| 0.450 | 0.1590 | 2.96 | 2.20 | 2.77 | 3.02 | |||||
| 0.500 | ±0.015 | 0.1963 | 2.39 | ±4% | 1.78 | ±4% | 2.24 | ±4% | 2.44 | ±4% |
| 0.560 | 0.2463 | 1.91 | 1.42 | 1.79 | 1.95 | |||||
| 0.630 | 0.3117 | 1.51 | 1.12 | 1.41 | 1.51 | |||||
| 0.710 | 0.3959 | 1.19 | 0.884 | 1.11 | 1.21 | |||||
| 0.750 | 0.4418 | 1.06 | 0.792 | 1.00 | 1.09 | |||||
| 0.800 | 0.5027 | 0.935 | 0.696 | 0.875 | 0.955 | |||||
| 0.850 | 0.5674 | 0.828 | 0.617 | 0.775 | 0.846 | |||||
| 0.900 | 0.6362 | 0.739 | 0.550 | 0.692 | 0.755 | |||||
| 0.950 | 0.7088 | 0.663 | 0.494 | 0.621 | 0.677 | |||||
| 1.000 | 0.7854 | 0.598 | 0.446 | 0.560 | 0.611 | |||||
| 1.060 | ±0.020 | 0.8852 | 0.533 | ±4% | 0.397 | ±4% | 0.499 | ±4% | 0.544 | ±4% |
| 1.120 | 0.9852 | 0.477 | 0.355 | 0.447 | 0.487 | |||||
| 1.180 | 1.094 | 0.430 | 0.320 | 0.402 | 0.439 | |||||
| 1.250 | 1.227 | 0.383 | 0.285 | 0.359 | 0.391 | |||||
| 1.320 | 1.368 | 0.343 | 0.256 | 0.322 | 0.351 | |||||
| 1.400 | 1.539 | 0.305 | 0.227 | 0.286 | 0.312 | |||||
| 1.500 | 1.767 | 0.266 | 0.198 | 0.249 | 0.272 | |||||
| 1.600 | 2.011 | 0.234 | 0.174 | 0.219 | 0.239 | |||||
| 1.700 | ±0.025 | 2.270 | 0.207 | ±4% | 0.154 | ±4% | 0.194 | ±4% | 0.211 | ±4% |
| 1.800 | 2.545 | 0.185 | 0.138 | 0.173 | 0.189 | |||||
| 1.900 | 2.835 | 0.166 | 0.123 | 0.155 | 0.169 | |||||
| 2.000 | 3.142 | 0.15 | 0.111 | 0.140 | 0.153 | |||||
| 2.120 | 3.530 | 0.133 | 0.0992 | 0.125 | 0.136 | |||||
| 2.240 | ±0.030 | 3.941 | 0.119 | ±4% | 0.0888 | ±4% | 0.112 | ±4% | 0.122 | ±4% |
| 2.360 | 4.374 | 0.107 | 0.0800 | 0.101 | 0.110 | |||||
| 2.500 | 4.909 | 0.0957 | 0.0713 | 0.0896 | 0.0978 | |||||
| 2.650 | 5.515 | 0.0852 | 0.0635 | 0.0798 | 0.0870 | |||||
| 2.800 | 6.158 | 0.0763 | 0.0568 | 0.0715 | 0.0780 | |||||
| 3.000 | 7.069 | 0.0665 | 0.0495 | 0.0622 | 0.0679 | |||||
| 3.150 | ±0.035 | 7.793 | 0.0603 | ±4% | 0.0449 | ±4% | 0.0565 | ±4% | 0.0616 | ±4% |
| 3.350 | 8.814 | 0.0533 | 0.0397 | 0.0499 | 0.0545 | |||||
| 3.550 | 9.898 | 0.0475 | 0.0354 | 0.0445 | 0.0485 | |||||
| 3.750 | 11.04 | 0.0426 | 0.0317 | 0.0398 | 0.0435 | |||||
| 4.000 | 12.57 | 0.0374 | 0.0279 | 0.0350 | 0.0382 | |||||
| 4.250 | 14.19 | 0.0331 | 0.0247 | 0.0310 | 0.0338 | |||||
| 4.500 | 15.90 | 0.0296 | 0.0220 | 0.0277 | 0.0302 | |||||
| 4.750 | ±0.040 | 17.72 | 0.0265 | ±4% | 0.0198 | ±4% | 0.0248 | ±4% | 0.0271 | ±4% |
| 5.000 | 19.63 | 0.0239 | 0.0178 | 0.0224 | 0.0244 | |||||
| 5.300 | ±0.050 | 22.06 | 0.0213 | ±4% | 0.0159 | ±4% | 0.0199 | ±4% | 0.0218 | ±4% |
| 5.600 | 24.63 | 0.0191 | 0.0142 | 0.0179 | 0.0195 | |||||
| 6.000 | ±0.060 | 28.27 | 0.0166 | ±4% | 0.0124 | ±4% | 0.0156 | ±4% | 0.017 | ±4% |
| 6.300 | 31.17 | 0.0151 | 0.0112 | 0.0141 | 0.0154 | |||||
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