Thermocouple Wire, W W26Re Tungsten Rhenium

temp_1Concept Alloys stocks and produces the W-W26Re alloy in wire form. Request a quote on our Type G W/W26Re wire.  Sizes stocked are shown below.

We take great pride in manufacturing high quality Tungsten-Rhenium wire – taking extreme measures to insure uniformity in size, diameter, and performance characteristics. Learn more.

 

Overview

The Type G W-W26Re combination was the earliest combination developed in the tungsten-rhenium thermocouple system. It suffers, however, from the brittle behavior of the pure tungsten positive leg. For this reason, the positive leg is generally shipped in the as-drawn condition. This results in an emf shift when the thermocouple is exposed to elevated temperatures (generally > 2000°F) in use. The primary advantage of the W/W26Re combination is the higher Seebeck coefficient obtained at temperatures > 900°F. Modern instrumentation minimizes the importance of this advantage.

Characteristics

  • Composition:  100% tungsten positive, 74% tungsten/26% rhenium negative
  • Wide temperature range:  320°F to over 5200°F (-196°C to over 2760°C)
  • High EMF
  • Pure tungsten positive leg exhibits brittle behavior
  • Good high temperature strength & stability
  • Very stable in inert atmospheres such as hydrogen, inert gases and vacuum
  • Susceptible to rapid oxidation at high temperatures
  • The cost of W/W26Re materials is relatively low compared to noble metals
  • Positive leg shipped in as-drawn condition / Negative leg shipped in a stabilized condition

Applications

  • Heat treat ovens
  • Hipping ovens

Technical Specifications

 

Stock Sizes (Inches/mm)
Inches mm
0.0005 0.013
0.0008 0.020
0.0030 0.076
0.0050 0.127
0.0078 0.198
0.0100 0.254
0.0150 0.381
0.0160 0.406
0.0200 0.508
0.0320 0.813
0.0400 1.016

Unless otherwise stated, all materials produced by Concept Alloys conform to ASTM E696 and E1751.

Type G Bare Wire & Insulation

W/W26Re thermocouples may be used bare, with hard fired ceramic insulators or in mineral insulated, metal sheathed (MIMS) cable.

Low temperature applications <3000°F insulators – common alumina or magnesia insulation is generally satisfactory. Use is limited by the melting point of alumina (3650°F) and the low electrical resistivity of magnesia above 3600°F.

At temperatures over 3000°F insulators of beryllia, havnia or thoria may be used. The most widely used is beryllia due to its higher electrical resistivity. Before selecting any insulator a thorough investigation should be conducted relative to material properties, chemical compatibility and necessary safety precautions. In MIMS constructions the selected sheath should be compatible with the insulators, wires and atmosphere. Materials that have been used successfully include tantalum, tungsten and some tungsten alloys, columbium, molybdenum and various ceramics.

Unless otherwise stated, all materials produced by Concept Alloys conform to ASTM E696, E230 and E1751.

Contact us to discuss Purchasing details to fit your specific requirements.