Designation and composition.

Grade	Nominal composition	Chinese standard	Nearest international reference
K	NiCr (approx. 90 % Ni - 10 % Cr)	NiSi (approx. 97 % Ni - 2.5 % Si)	IEC 60584-1 · ASTM E230
E	NiCu (approx. 63 % Ni - 37 % Cu)	Constantan (approx. 55 % Cu - 45 % Ni)	IEC 60584-1 · ASTM E230
J	Iron (Fe, high purity)	Constantan (approx. 55 % Cu - 45 % Ni)	IEC 60584-1 · ASTM E230
T	Copper (Cu, high purity)	Constantan (approx. 55 % Cu - 45 % Ni)	IEC 60584-1 · ASTM E230

Scroll the table sideways to see all columns.

Electrical & dimensional

Supply range and condition.

Property	Value
Type K - best for	General industrial use, widest range, approx. -200 to +1350 °C
Type E - best for	Highest sensitivity, low-to-mid temperature, approx. -200 to +900 °C
Type J - best for	Reducing atmospheres and acid fumes (iron leg), approx. -210 to +760 °C
Type T - best for	Lowest temperature, most precise of the four, approx. -250 to +350 °C
Diameter range	0.10 - 6.00 mm
Temper	M (soft)
Supply form	Matched positive / negative pair from the same melt, shipped together
Chinese standards	`GB/T 2614-1998`, `GB/T 4993 / 4994-1998`, `GB/T 2903-1998`

Values above are nominal. Composition, resistivity, temperature coefficient of resistance (TCR) and thermal EMF are confirmed by the inspection report issued with each shipment - this page confirms feasibility and range, it is not the inspection certificate.

Typical applications

Where this grade is specified.

Thermocouple and temperature-probe manufacture
Mineral-insulated (MI) cable and sheathed thermocouples
Compensating leads and instrument cable
Matched positive / negative legs supplied together

What "matched pair" means: both legs of a pair are drawn from the same melt and dispatched together, so the thermal-EMF behaviour is consistent along the whole length. Pairing and thermal-EMF verification against the reference tables is available per batch; reference-grade calibration certificates are arranged through an accredited partner laboratory.

Which type? Range is the constraint -> K. Sensitivity below 900 °C -> E. Reducing atmosphere -> J. Lowest temperature and highest precision -> T. Full comparison.

Type K Type E Type J Type T Matched pairs

Thermocouple Wire coil — Thermocouple Wire - supplied in the temper your drawing calls for.

Order facts

What you need before you send a drawing.

Minimum orderSample 100 g at cost · orders from 1 kg · production pricing from 5 kg

Standard lead time3 - 7 days from order confirmation

Temper suppliedM (soft)

Diameter0.10 - 6.00 mm round wire

HS classificationHS 7505.22 (types K / E); HS 74xx / 72xx by leg (types J / T)

DocumentsMaterial test certificate standard; pairing and thermal-EMF verification per batch on request

All six families Request a Quotation

Export & compliance

Stated plainly, not oversold.

Export note - nickel-containing material to the United States: assess California Prop 65 (metallic nickel is listed with no safe harbour). To the EU: observe REACH nickel release limits and the General Product Safety Regulation (GPSR), which applies from 2026-06-01 and requires an EU-based responsible person. Bare alloy wire is a raw material, not a finished electrical device, so UL / CSA / CE device marks do not apply to it. Composition, resistivity, TCR and thermal EMF are stated as nominal on this page and are confirmed by the inspection report issued with each shipment.

Related selection notes: K vs E vs J vs T · NiCr 80/20 vs 60/15 · Wire for an MI cable

Next step

Send the grade, diameter, temper and quantity.

Tell us what the wire has to do and the date your line needs it. We come back with a confirmed lead time, the achievable tolerance and the documents we can issue. Sample 100 g at cost; orders from 1 kg; production pricing from 5 kg.

Request a Quotation Samples & trial orders

Thermocouple Wire - Types K, E, J and T, supplied as matched pairs