Type K Thermocouple Wire: Chromel / Alumel, −200 … +1370 °C
Chromel (NiCr 90/10)
Alumel (NiAl 95/5 + Mn 2/Si 1)
±1.5°C (0–375°C) / ±0.4% (375–1000°C)
Industry standard for general-purpose high-temperature measurement. Wide temperature range, good oxidation resistance in clean oxidising atmospheres.
Avoid reducing atmospheres (800–1050°C). Susceptible to green-rot chromium oxidation. Not for vacuum above 800°C without protection.
Technical Specifications
| Property | Specification |
|---|---|
| Diameter Range | φ0.025mm – φ5.0mm |
| Tolerance | ±0.005mm (fine) / ±0.02mm (standard) |
| Temperature Range | −200 … +1370 °C |
| Standards | IEC 60584-1 Class 1 / ASTM E230 / DIN EN 60584 |
| Surface Finish | Bright / Oxidised / Electro-polished |
| Packaging | DIN 125 spool / Coil / Custom reel |
| Coil Weight | 5kg / 10kg / 20kg standard |
| Traceability | Furnace batch number engraved on spool |
Available Product Forms
Bare Wire →
Solid single-strand, φ0.025–5.0 mm, bright or oxidised.
Stranded Wire →
Multi-strand for flexibility and vibration resistance. 7/19/37 strand.
How to specify Type K Thermocouple Wire
- Confirm the alloy for your operating temperature — Chromel / Alumel, rated −200 … +1370 °C.
- Check the atmosphere before ordering — Avoid reducing atmospheres (800–1050°C). Susceptible to green-rot chromium oxidation. Not for vacuum above 800°C without protection.
- Choose the product form — Bare Wire or Stranded Wire. For Type K Thermocouple Wire the deciding factor is the service condition: industry standard for general-purpose high-temperature measurement. Wide temperature range, good oxidation resistance in clean oxidising atmospheres.
- Fix the conductor diameter within φ0.025mm – φ5.0mm (±0.005mm (fine) / ±0.02mm (standard)).
- Quote against IEC 60584-1 Class 1 and request the MTC / EMF calibration certificate with the furnace batch number — state which Type K Thermocouple Wire form you need so the certificate scope matches the delivered conductor.
Frequently Asked Questions
What is the maximum temperature for Type K thermocouple wire?
+1370 °C, across a −200 °C to +1370 °C range. In clean oxidising atmospheres Type K is the industry standard for general-purpose high-temperature measurement.
Why should Type K be avoided in reducing or vacuum atmospheres?
Between 800 °C and 1050 °C the Chromel leg suffers green-rot chromium oxidation, which produces a large negative EMF drift. In vacuum or reducing service above 800 °C, specify Type N.
What tolerance is Type K wire supplied to?
IEC 60584-1 Class 1 and ASTM E230, with EMF tolerance ±1.5 °C (0–375 °C) / ±0.4% (375–1000 °C).
What forms is Type K available in?
Bare wire (solid, φ0.025–5.0 mm) and stranded wire (7/19/37 strand, φ0.1–5.0 mm), both with furnace-batch traceability.
Bottom line: Type K is the default choice across −200 °C to +1370 °C in clean oxidising air, with the widest availability of connectors, instruments and reference data. It is the wrong choice in vacuum or reducing atmospheres above 800 °C, where green-rot chromium oxidation drives the reading down — specify Type N there.