The Fe-CuNi thermocouple wire (type J) is sometimes also referred to as Fe-constantan thermocouple wire. The chemical composition for positive leg Fe (JP) is pure Iron, and Copper-Nickel alloy (Cu: Ni≈ 55%: 45%) is used to make the negative leg Constantan (JN). Although JN, EN and TN are all called Constantan, JN is not interchangeable with EN and TN because of different EMF output curve.
The Fe-CuNi (Constantan) thermocouple wire is known for its good linearity, high EMF output, high sensitivity and outstanding stability. Designed with an operating temperature range of -210 to 1200 ℃, the product is usually used at 0 to 750 ℃ to avoid fast oxidation of positive leg iron under high temperatures. The wire can accommodate vacuum, oxidizing, reducing or inert atmospheres, but using it in a sulphurous atmosphere above 500 ℃ without any protection is not recommended.Thermocouple Temperature Range and Tolerance
|Name||Calibration type||Grade||Operating temperature range (℃)||Temperature range (℃)||Tolerance||Standard|
|Long term||Short term|
|Fe-CuNi (Constantan) Thermocouple Wire (Type J)||J||I||600||750||-40~750||+1.5℃ or +0.4%t||GB/T4994|
|Ⅱ||+2.5℃ or +0.75%t|
|* Operating temperature range (℃) is applicable to the product of Ø3.2mm.|
As a specialized Fe-CuNi (constantan) thermocouple wire (type J) manufacturer and supplier in China, we also provide constantan electrical resistance wire, silicone rubber heating plate, Teflon heating wire, and anti-freeze pipe heating cable, among others.
Iron-constantan Thermocouple Cable | Thermocouple Wire with Upper Temperature Limit