Cuprothal® SX

Thermocouple wireDatasheet

Datasheet updated 2025-10-01 11:49 (supersedes all previous editions)

Disclaimer: Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice. This datasheet is only valid for materials under the trademark Kanthal^®.

Cuprothal^® SX is a copper-nickel alloy (CuNi alloy) used for the negative leg of compensating cables for thermocouples type S/R. Cuprothal^® SX must be matched with electrolytic copper (ASTM B3) to meet the reference standard.

Chemical composition

	Cu %	Ni %	Mn %
Nominal composition	Bal.	3.0	2.0

Mechanical properties

Wire size	Yield strength	Tensile strength	Elongation
Ø	R_p0.2	R_m	A
mm	MPa	MPa	%
0.32	-	330	30

Physical properties

Density g/cm³	8.91
Electrical resistivity at 20°C Ω mm²/m	0.12
Temperature coefficient of resistivity between 20°C and 100°C 10^-6/K	1500

Coefficient of thermal expansion
Temperature °C	Thermal Expansion x 10^-6/K
20 - 100	16

Melting point °C	1080
Magnetic properties	The material is non-magnetic

Thermoelectric properties

Nominal emf values vs electrolytic copper (ASTM B3)
Temperature °C	100	200
mV	0.646	1.441

ITS 90 - Reference junction 0°C