Refractory Metal Type C Thermocouple (W5Re/W26Re)
ASTM E230 Type C · ISO 27043 Type C
Type C thermocouple is a matched pair of refractory-metal wires — W-5%Re as the positive leg and W-26%Re as the negative leg — supplied to ASTM E230 Type C as bare wire pairs, as-drawn or annealed single legs, and MgO-insulated mineral-sheathed assemblies.
Reference datasheet — Type C Thermocouple (W5Re/W26Re) is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Type C Thermocouple (W5Re/W26Re) tempers and conditions
Type C Thermocouple (W5Re/W26Re) is supplied in 4 conditions, soft to hard.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
W-5%Re positive leg | Softer, drift-stabilised positive leg for tight-radius routing and for sensors that must be pre-aged before calibration. | 550 | 800 | 14 | 420 HV | 14.4 % IACS |
W-26%Re negative leg | Annealed negative leg for maximum room-temperature ductility during coiling, welding and sheath insertion. | 700 | 1,000 | 18 | 480 HV | 6.2 % IACS |
W-5%Re positive leg | Positive leg in the stiffest, strongest condition; use where the wire must be self-supporting or threaded through long insulators before first heat-up. | 1,650 | 1,900 | 3 | 580 HV | 14.4 % IACS |
W-26%Re negative leg | Negative leg as supplied on spool; the rhenium ductilising effect keeps it bendable at room temperature despite very high strength. | 1,850 | 2,200 | 5 | 620 HV | 6.2 % IACS |
Supply forms, finishes and certifications
Ways Type C Thermocouple (W5Re/W26Re) is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
MI-SHEATH | Mineral-insulated sheathed assembly | Supply option |
PAIR-ADDefault | Matched pair, as-drawn thermocouple-grade wire | Supply option |
What is Type C Thermocouple (W5Re/W26Re)?
Type C thermocouple is a matched pair of refractory-metal wires — W-5%Re as the positive leg and W-26%Re as the negative leg — supplied to ASTM E230 Type C as bare wire pairs, as-drawn or annealed single legs, and MgO-insulated mineral-sheathed assemblies. Engineers specify it to read up to about 2320 °C in vacuum or inert atmospheres, where the drawn wire carries roughly 1750 MPa yield and 2050 MPa tensile strength at about 4% elongation. It cannot be used bare in air or other oxidising atmospheres, and after high-temperature exposure the legs recrystallise and turn brittle, so installed loops must not be disturbed; platinum-rhodium types cover lower-temperature oxidising service. Type C Thermocouple (W5Re/W26Re) has a density of 19.5 g/cm³ (0.704 lb/in³), heavier than 96% of refractory metal grades. It melts at 3,150°C (5,702 °F). Type C Thermocouple (W5Re/W26Re) has a yield strength of 1,700 MPa (247 ksi) and a tensile strength of 2,000 MPa (290 ksi) — stronger than 97% of refractory metal grades. Elongation at break is 4% and the elastic modulus is 395 GPa (57.3 Msi).
What is Type C Thermocouple (W5Re/W26Re) used for?
- vacuum furnace temperature measurement
- metal processing and sintering monitoring
- aerospace propulsion test instrumentation
Advantages
- High service temperature — 2,320°C (4,208 °F), better than 98% of refractory metal grades
- High strength — 1,700 MPa (247 ksi), better than 97% of refractory metal grades
- Stiff — 395 GPa (57.3 Msi), better than 94% of refractory metal grades
Limitations
- Needs corrosion protection — 35/100, worse than 99% of refractory metal grades
- Heavy — 19.5 g/cm³ (0.704 lb/in³), worse than 96% of refractory metal grades
- Difficult to machine — 8/100, worse than 92% of refractory metal grades
- Limited ductility — 4%, worse than 84% of refractory metal grades
Type C Thermocouple (W5Re/W26Re) properties
Typical room-temperature values; bars are the position among refractory metal grades.
Physical3
Type C Thermocouple (W5Re/W26Re) has a density of 19.5 g/cm³ (0.704 lb/in³), heavier than 96% of refractory metal grades. It melts at 3,150°C (5,702 °F).
Mechanical8
Type C Thermocouple (W5Re/W26Re) has a yield strength of 1,700 MPa (247 ksi) and a tensile strength of 2,000 MPa (290 ksi) — stronger than 97% of refractory metal grades. Elongation at break is 4% and the elastic modulus is 395 GPa (57.3 Msi).
Thermal6
Type C Thermocouple (W5Re/W26Re) is rated for continuous service to 2,320°C (4,208 °F). It conducts heat at 70 W/m·K (40.4 BTU/hr·ft·°F), better than 71% of refractory metal grades. Thermal expansion is 4.7 µm/m·K (2.61 µin/in·°F).
Electrical3
Type C Thermocouple (W5Re/W26Re) conducts electricity at 9 % IACS, better than 62% of refractory metal grades.
Chemical & Environmental2
Corrosion resistance is fair (35/100), worse than 99% of refractory metal grades.
Sustainability4
Producing a kilogram of Type C Thermocouple (W5Re/W26Re) takes about 500 MJ of energy and emits 35 kg of CO₂ — less than 70% of refractory metal grades. Typical recycled content is 10%.
Manufacturability8
Type C Thermocouple (W5Re/W26Re)'s machinability is not recommended (8/100, worse than 92% of refractory metal grades); weldability poor (30/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the refractory metal family
Yield strength against density for every refractory metal grade FabDigit runs. Type C Thermocouple (W5Re/W26Re) is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Type C Thermocouple (W5Re/W26Re)
Is Type C Thermocouple (W5Re/W26Re) easy to machine?
Not a machining alloy — wire is drawn to final size; cut with abrasive/EDM or shear, never turned or drilled.
Can Type C Thermocouple (W5Re/W26Re) be welded?
Form the measuring junction by capacitive-discharge, laser or EB butt/ball welding under argon or vacuum; keep the joint free of oxygen and carbon, and never fusion-weld recrystallized wire.
Can Type C Thermocouple (W5Re/W26Re) be formed, bent or molded?
Bend only in the as-drawn or annealed state at room temperature and above ~10× wire diameter; after high-temperature service the wire recrystallizes and becomes glass-brittle, so leave installed loops undisturbed.
Type C Thermocouple (W5Re/W26Re) chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Renegative (–) leg W-26Re | 24.5 – 27 | 26 |
| Motypical impurity limit | ≤ 0.02 | |
| Fetypical impurity limit | ≤ 0.01 | |
| Nitypical impurity limit | ≤ 0.01 | |
| Ccarbon must be low — carburisation shifts EMF | ≤ 0 | |
| Otypical impurity limit | ≤ 0.01 | |
| other, totalthermoelement purity governs calibration | ≤ 0.05 | |
| Wbalance in both legs | balance |
What surface finishes work on Type C Thermocouple (W5Re/W26Re)?
Degrease and electro/chemically clean (alkaline ferricyanide) before insulator threading; no anodizing or plating — protection comes from the vacuum, inert gas or ceramic/refractory sheath.
Equivalent designations
Standards and trade names that resolve to Refractory Metal Type C Thermocouple (W5Re/W26Re) in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- E230 Type C
- ISO
- 27043 Type C
How much does Type C Thermocouple (W5Re/W26Re) cost?
Type C Thermocouple (W5Re/W26Re) is a high-cost refractory metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Type C Thermocouple (W5Re/W26Re) — frequently asked
What is Type C Thermocouple (W5Re/W26Re) used for?
Type C Thermocouple (W5Re/W26Re) is typically used for vacuum furnace temperature measurement, metal processing and sintering monitoring and aerospace propulsion test instrumentation. In short: reads to 2320 °C; vacuum and inert use only; matched W-Re wire pair.
What is the yield strength of Type C Thermocouple (W5Re/W26Re)?
Type C Thermocouple (W5Re/W26Re) has a typical yield strength of 1,700 MPa (247 ksi) and a tensile strength of 2,000 MPa (290 ksi) — stronger than 97% of refractory metal grades. Strength varies by condition: see the 4 listed tempers.
Is Type C Thermocouple (W5Re/W26Re) easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 92% of refractory metal grades). Not a machining alloy — wire is drawn to final size; cut with abrasive/EDM or shear, never turned or drilled.
Can Type C Thermocouple (W5Re/W26Re) be welded?
Not readily — weldability is rated poor (30/100). Form the measuring junction by capacitive-discharge, laser or EB butt/ball welding under argon or vacuum; keep the joint free of oxygen and carbon, and never fusion-weld recrystallized wire.
What surface finishes work on Type C Thermocouple (W5Re/W26Re)?
Degrease and electro/chemically clean (alkaline ferricyanide) before insulator threading; no anodizing or plating — protection comes from the vacuum, inert gas or ceramic/refractory sheath.
Can Type C Thermocouple (W5Re/W26Re) be formed, bent or molded?
Bend only in the as-drawn or annealed state at room temperature and above ~10× wire diameter; after high-temperature service the wire recrystallizes and becomes glass-brittle, so leave installed loops undisturbed.
What is the maximum service temperature of Type C Thermocouple (W5Re/W26Re)?
Type C Thermocouple (W5Re/W26Re) is rated for continuous use to about 2,320°C (4,208 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Type C Thermocouple (W5Re/W26Re) cost?
Type C Thermocouple (W5Re/W26Re) is a high-cost refractory metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM E988 — Temperature-EMF Tables for Tungsten-Rhenium Thermocouples — ASTM International (2019)
- ASTM E230/E230M — Standard Specification and Temperature-EMF Tables for Standardized Thermocouples — ASTM International (2023)
- ASTM E1751/E1751M — Guide for Temperature-EMF Tables for Non-Letter-Designated Thermocouple Combinations — ASTM International (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (refractory metals) — ASM International (1990)
- ASM Handbook Vol. 3 — Alloy Phase Diagrams (W-Re system) — ASM International (2016)
- Tungsten-Rhenium alloy wire and thermocouple data — Rhenium Alloys Inc. / Plansee (2023)
- Type C thermocouple application and limits-of-error data — Omega Engineering (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.