Type C and Type D, Thermocouple Wire Tungsten Rhenium Alloy

Type C is Tungsten 5% Rhenium vs Tungsten 26% Rhenium. Type D has a slightly different composition: Tungsten 3 % Rhenium vs Tungsten 25% Rhenium.

Thermocouples are one of the most commonly used temperature sensors. They are available in a wide range, each developed with specific characteristics, durability, resistance and temperature range to solve a particular application challenge. Here we look at two of the  tungsten thermocouples, Type C and Type D. These have been developed to facilitate ultra-high temperature measurement in vacuum, reducing or inert atmospheres.

These thermocouple wires  are both Tungsten Rhenium alloys. Type C is Tungsten 5% Rhenium vs Tungsten 26% Rhenium. Type D has a slightly different composition: Tungsten 3 % Rhenium vs Tungsten 25% Rhenium. Both of these thermocouples can be used for guaranteed temperature measurement up to 2871°C.


What are the differences between thermocouples Type C and Type D?

These two thermocouples are very similar in composition, ductility and performance. The only slight differences are that the  average EMF of Type D  is marginally higher than that of Type C. Furthermore, Type C is the only ASTM approved tungsten thermocouple while “Type D” is in fact an industry term and not an official standard thermocouple letter designation.

Type C (W5Re/W26Re) thermocouples are by far the most commonly used. However,  there are some applications where Type D is specifically requested by customers. Kamet is  able to supply both types from our webshop.


Industrial uses of Tungsten Rhenium Alloys

Tungsten thermocouples are the ideal choice for high temperature vacuums as well as either  hydrogen or other inert gas environments. They are specifically selected for temperatures and conditions  beyond the capabilities of platinum.  Avoid usage of Type C and Type D thermocouple wires are in the presence elevated temperatures in oxygen, nitrogen or hydrogen due to embrittlement

Vacuum furnaces at extreme temperatures are one of the most common applications of these thermocouples. Others include:

  • Aerospace
  • (Solar) Power generation
  • Semiconductor processing and equipment
  • (Medical) Research
  • Military

Kamet’s Tungsten Rhenium thermocouple wire products

Together with our partner and expert manufacturer, Concept Alloys, Kamet offers a variety of high quality  Type C and Type D thermocouple via our webshop with two week delivery time. Our products offer the following  advantages:

  • Calibration up to 2315°C through actual testing and not extrapolation
  • Full traceability and certification to NIST standards
  • Certifications are user-friendly,  with deviations indicated in mV, °F, or °C
  • Wire sizes  0.0127 to 1 mm diameter and larger diameters are available.
  • Type C and Type D wires are supplied at both standard and customized lengths with no upper limit.
  • The thermocouple wires  are doped which ensures superior ductility in comparison to un-doped materials.
  • Extra services are available such as;
    – Customized EMF tolerances and sizes for critical applications
    – The recording of calibration data from both ends of long-length spools (end to end)  instead of an average.

Depending on the demands (environment and temperature) of the application, these thermocouples can be used bare, with ceramic insulators or in mineral insulated (MI) cable with a metal sheath. All these variations are available in our webshop or through a custom order.  To ensure accuracy and durability it is essential to make a thorough assessment of the application so that the correct configuration of insulators, wires and atmosphere is achieved. The in-house experts at Kamet are able to support and advise you in this process.


Physical Properties of Tungsten Rhenium Alloys

Download the product sheet op Type C and Type D thermocouple for the mechanical and physical properties.

Tungsten Rhenium Alloys datasheet


Kamet and Concept Alloys

Based in the United States and founded in 2002,  Concept Alloys is our partner for Tungsten Rhenium thermocouple wire. Concept Alloys are  widely known for their proprietary testing and calibration methodologies used to routinely calibrate each end of every coil produced. This expertise and commitment to quality is further reflected in the fact that every finished coil has to  meet their own end-to-end uniformity tolerance every 100°C, from +100°C to +2300°C. They have extensive experience in Tungsten Rhenium alloys and have built up unparalleled knowledge to provide great technical support.  Furthermore, the company works with New Product Development teams in order to further knowledge on temperature measurement, and oxidation and corrosion resistance for Tungsten Rhenium alloys.

This  commitment to quality, the focus on in-house expertise and  innovative approach matches the business ethic of Kamet perfectly.

Kamet furthermore offers her customers:

  • Excellent customer service via phone or mail. Our multilingual team will ensure you receive a response within 24 hours.
  • Kamet provides 24hour access to a large range of products via the webshop as well as extensive product information on the website.
  • Our expert technical sales engineers are available to work with you in finding the best (custom) product for your situation
  • All the parts are in stock  meaning we can provide a customized thermocouple within a week.

Kamet Webshop

Kamet Trading has a webshop stocked with items from our wharehouse. Please visit the webshop and browse through our available products. You can directly see the product details and request a quotation.


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