Kamet provides various high temperature thermocouple types: S, R, B, C and D. Each thermocouple type has its advantage and can be completely customized to your requirements.
| Thermocouple | Type | Symbol | Standard limits of error* | Recommended temperature range | |
|---|---|---|---|---|---|
| + | – | Per ASTM E 230 | |||
| Pt10%Rh | Pt | S | S | ± 1.5°C or 0.25% per ASTM E 230 | 0-1450°C |
| Pt13%Rh | Pt | R | R | ± 1.5°C or 0.25% per ASTM E 230 | 0-1450°C |
| Pt30%Rh | Pt6%Rh | B | B | ± 0.5% per ASTM E 230 | 870-1700°C |
| W5%Re | W26%Re | C | AE | ± 4.4°C (0-426°C) ± 1% (426-2315°C per ASTM E 988) | 0-2200°C |
| W3%Re | W25%Re | D | AO | ± 4.4°C (0-426°C) ± 1% (426-2315°C per ASTM E 988) | 0-2200°C |
What is difference between Type S and type R thermocouples?
Type S and Type R thermocouples are technically very similar. The only difference is that the positive leg of a Type R consists of 87%Pt, 13%Rh and a Type S of 90%Pt, 10%Rh.
The main difference between type S and R is the higher percentage of Rhodium in the type R. This makes this thermocouple cable more expensive yet gives a (small) higher output and is overall a bit more stable than the type S. Type S sensitivity is between 6 and 12 µV/°C. Type R has a sensitivity between 6 and 14µV/°C.
Both type R and type S thermocouples can cover a temperature range of 0°C to 1450°C with uncertainties as good as 0.15°C over most of the range.
What is the difference between Type C and Type D thermocouples?
The positive leg of a Type C thermocouple consists of 95% Tungsten, 5% Rhenium while the positive leg of a Type D wire consists of 97% Tungsten, 3% Rhenium. The slight difference in output is that the average EMF of Type D is marginally higher than that of Type C.
It is better to not use Type D thermocouples in temperatures below 500° C. More about Type C and D thermocouple wire.
Mechanical properties and physical properties
| Tungsten | W3Re | W5Re | W25/26 Re | |
|---|---|---|---|---|
| Tensile Strength, ann. (x 103 psi) 8°F 1832°F 3632°F | 80 35 15 | 172 60 10 | 220 65 26 | 200 95 24 |
| Elongation (% in 10”) 68°F 1832°F 3632°F | 0 10 23 | 15 18 23 | 20 24 24 | 11 19 27 |
| Resistivity (W · circ. mil / ft.) 68°F 1832°F 3632°F | 33 199 398 | 57 228 420 | 70 235 434 | 170 331 524 |
| Therm. Exp. Coef. (in./in./°F) 68°F 1832°F 3632°F | 1.7×10-6 2.3×10-6 3.1×10-6 | 2.9 x 10-6 3.1 x 10-6 3.9 x 10-6 | ||
| Density g./cm3 lb./in3 | 19.3 0.697 | 19.4 0.700 | 19.4 0.701 | 19.7 0.714 |
| Melting Point °C °F | 3410 6170 | 3325 6017 | 3350 6062 | 3120 5648 |