Type J, Fe-CuNi thermocouple is a widely used thermocouple junction. In general, it is economically priced and it has a smaller temperature range compared to other thermocouple junctions: -210°C to +750°C. Type J thermocouples are favored for their low cost and high EMF, making them suitable for industrial applications.
These thermocouple wires feature iron-constantan conductors but have a slightly smaller temperature range compared to type K thermocouples and are not ideal for oxidizing environments. Caution is advised as the iron leg can rust if exposed to moisture.
| Thermocouple | Class | Outside Diameter in mm | On Stock | |
|---|---|---|---|---|
| Type J wire | Class 1 | 0.30 mm | 5 week delivery time | Send inquiry |
| Type J wire | Class 1 | 0.80 mm | 5 week delivery time | Send inquiry |
| Type J wire | Class 1 | 0.80 mm | Yes | Send inquiry |
| Type J wire | Class 1 | 1.00 mm | Yes | Send inquiry |
| Type J wire | Class 1 | 1.50 mm | 5 week delivery time | Send inquiry |
| Type J wire | Class 1 | 2.00 mm | Yes | Send inquiry |
| Type J wire | Class 1 | 3.00 mm | 5 week delivery time | Send inquiry |
Please contact us if you need different diameters. We can supply more custom made diameters (combinations) than stated above.
Approximate working temperature tange;
Please note that these ranges are given as indicative values and vary per diameter.
| Alloy | Fe | Ni | Cu |
|---|---|---|---|
| JP ( + ) | 100 | – | – |
| JN (-) | – | 45 | 55 |
| JP | JN | |
|---|---|---|
| Density (g/cm3) | 7.86 | 8.90 |
| Melting point (°C) | 1535 | 1210 |
| Resistivity | 1535 | 1210 |
| Temp. coef. of resistance (x10-6/°C) | 5000 | 60 |
| Linear expansion (coef. x10-6/°C) | 11.7 | 14 |
| Thermal Conductivity (W m-1 °C-1 at 20°C) | 66.2 | 21.2 |
The type J thermocouple stands out for its affordability and efficiency in temperature monitoring of inert materials, vacuum applications, and hot processes including the manufacturing of plastics and resins. It is particularly effective in reducing atmospheres.
It exhibits resilience to aging, despite this, it is prone to rapid degradation in oxidizing atmospheres above 550°C. The thermocouple’s maximum sustainable operating temperature is approximately 800°C, but it can withstand up to 1000°C for brief durations. The minimum working temperature is set at -210°C; however, users should be cautious of condensation below ambient temperatures, which can lead to rusting of the iron component and low temperature embrittlement.
It should be noted that the accuracy of type J may be significantly compromised if used above 760°C, and its use is not advised in damp environments or for low temperature monitoring due to oxidation concerns.
| °C | 0 | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 |
| 0 | 0 | 0.507 | 1.019 | 1.536 | 2.058 | 2.585 | 3.115 | 3.649 | 4.186 | 4.725 | 5.268 |
| 100 | 5.268 | 5.812 | 6.359 | 6.907 | 7.547 | 8.008 | 8.56 | 9.113 | 9.667 | 10.222 | 10.777 |
| 200 | 10.777 | 11.332 | 11.887 | 12.442 | 12.998 | 13.553 | 14.108 | 14.663 | 15.217 | 15.771 | 16.325 |
| 300 | 16.325 | 16.879 | 17.432 | 17.984 | 18.537 | 19.089 | 19.64 | 20.192 | 20.743 | 21.295 | 21.846 |
| 400 | 21.846 | 22.397 | 22.949 | 23.501 | 24.054 | 24.607 | 25.161 | 25.716 | 26.272 | 26.829 | 27.388 |
| 500 | 27.388 | 27.949 | 28.511 | 29.075 | 29.642 | 30.21 | 30.782 | 31.356 | 31.933 | 32.513 | 33.096 |
| 600 | 33.096 | 33.683 | 34.273 | 34.867 | 35.464 | 36.066 | 36.671 | 37.28 | 37.893 | 38.51 | 39.13 |
| 700 | 39.13 | 39.754 | 40.382 | 41.013 | 41.647 | 42.283 | 42.922 | 43.563 | 44.207 | 44.852 | 45.498 |
| 800 | 45.498 | 46.144 | 46.79 | 47.434 | 48.076 | 48.716 | 49.354 | 49.989 | 50.62 | 51.249 | 51.875 |
Do you have any further questions? Please let us know and our specialists will be happy to advise you.
