This specification covers the requirements for bare, solid conductor,  rhenium and tungstenalloy thermoelements having diameters of 0.13 mm (0.005 in.) to 0.5 mm (0.020 in.)supplied in matched pairs. These thermoelements is suitable for use either in bead-insulated, bare-wire thermocouples, or in compacted metal-sheathed, ceramic insulated thermocouple material or assemblies.
This specification covers the thermocouple combinations of tungsten-3 % rhenium versus tungsten-25 % rhenium (W3RE/W25RE) and tungsten-5 % rhenium versus tungsten-26 % rhenium (W5RE/W26RE). All information applies to both combinations unless otherwise noted.
 

Positive thermoelement:
The positive thermoelement for the RheniumTungsten3/RheniumTungsten25 combination have a nominal composition of 97 % tungsten and 3 % rhenium.
The positive thermoelement for the RheniumTungsten5/RheniumTungsten26 combination have a nominal composition of 95 % tungsten and 5 % rhenium.
The positive thermoelement is doped by the addition of potassium, silicon, and aluminum compounds or
otherwise stabilized by the addition of volatile substances that promote desirable grain structure and workability and maintain ductility after high temperature use.
 

The negative thermoelement for the  RheniumTungsten3/RheniumTungsten25 combination have a nominal composition of 75 % tungsten and 25 % rhenium.
The negative thermoelement for the RheniumTungsten5/RheniumTungsten26 combination have a nominal composition of 74 % tungsten and 26 % rhenium.
Ordering Information
 

1.1 Thermocouple Wire Composition— May be doped RheniumTungsten3/RheniumTungsten25  or doped RheniumTungsten5/RheniumTungsten26 1.2 Wire Size—Specify size with each order.
1.3 Wire Length—Specify total amount of each wire and minimum continuous length.
1.4 Thermocouple Calibration—Paired wires is furnished to the initial calibration tolerances
1.5 Required Mechanical Properties
1.6 Instructions for Spooling, Packaging, and Labeling—Wires is supplied on spools of a nominal 100 mm (4-in.)diameter core and boxed individually, unless otherwise requested.
Each spool is marked to identify the wire composition, diameter, quantity, processor’s name, spool designation and customers purchase order number in a manner to identify the pair of wires to be used to form a thermocouple meeting the calibration requirement.
1.7 Tests and Certifications Required from the Processor—Unless otherwise requested, the processor supply a certificate with each order stating the wire composition, size and calibration information.

The diameter of each wire is uniform end-to-end to within 0.01 mm (0.0005 in.) for 0.5 mm (0.02 in.) diameter wire and smaller.
The wires is solid, round, smooth and be free of weld joints, slivers, kinks, pits or nicks exceeding 5 % of
diameter.
The wire surface is uniformly clean and free of discoloration.
The thermoelements is heat treated to provide the specified ductility

Special sizes are available, please contact sales for inquiries.