Refractory Metal Type C Thermocouple (W5Re/W26Re) W26Re-ANN
Heat-treated state
ASTM E230 Type C · ISO 27043 Type C
W26Re-ANN = w-26%Re negative leg
Annealed negative leg for maximum room-temperature ductility during coiling, welding and sheath insertion.
Values for the W26Re-ANN condition
Other Type C Thermocouple (W5Re/W26Re) tempers and conditions
Type C Thermocouple (W5Re/W26Re) is listed in 4 conditions; see the grade overview at Type C Thermocouple (W5Re/W26Re).
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 |
W26Re-ANNThis page 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 |
What is Type C Thermocouple (W5Re/W26Re) W26Re-ANN?
Type C Thermocouple (W5Re/W26Re) W26Re-ANN is Type C Thermocouple (W5Re/W26Re) heat treated to W26Re-ANN — annealed negative leg for maximum room-temperature ductility during coiling, welding and sheath insertion. Type C Thermocouple (W5Re/W26Re) W26Re-ANN has a yield strength of 700 MPa (102 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 87% of refractory metal grades. Elongation at break is 18% and the elastic modulus is 395 GPa (57.3 Msi). Type C Thermocouple (W5Re/W26Re) W26Re-ANN has a density of 19.7 g/cm³ (0.712 lb/in³), heavier than 97% of refractory metal grades. It melts at 3,150°C (5,702 °F).
Advantages
- High service temperature — 2,320°C (4,208 °F), better than 98% of refractory metal grades
- Stiff — 395 GPa (57.3 Msi), better than 94% of refractory metal grades
- High strength — 700 MPa (102 ksi), better than 87% of refractory metal grades
Limitations
- Needs corrosion protection — 35/100, worse than 99% of refractory metal grades
- Heavy — 19.7 g/cm³ (0.712 lb/in³), worse than 97% of refractory metal grades
- Difficult to machine — 8/100, worse than 92% of refractory metal grades
Type C Thermocouple (W5Re/W26Re) W26Re-ANN properties
Typical room-temperature values for Type C Thermocouple (W5Re/W26Re) W26Re-ANN; 11 are specific to this condition. Other listed values are Type C Thermocouple (W5Re/W26Re) reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
Type C Thermocouple (W5Re/W26Re) W26Re-ANN has a density of 19.7 g/cm³ (0.712 lb/in³), heavier than 97% of refractory metal grades. It melts at 3,150°C (5,702 °F).
Mechanical8
Type C Thermocouple (W5Re/W26Re) W26Re-ANN has a yield strength of 700 MPa (102 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 87% of refractory metal grades. Elongation at break is 18% and the elastic modulus is 395 GPa (57.3 Msi).
Thermal6
Type C Thermocouple (W5Re/W26Re) W26Re-ANN is rated for continuous service to 2,320°C (4,208 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 61% of refractory metal grades. Thermal expansion is 4.7 µm/m·K (2.61 µin/in·°F).
Electrical3
Type C Thermocouple (W5Re/W26Re) W26Re-ANN conducts electricity at 6.2 % IACS, better than 51% 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) W26Re-ANN 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) W26Re-ANN's machinability is not recommended (8/100, worse than 92% of refractory metal grades); weldability poor (30/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Type C Thermocouple (W5Re/W26Re) W26Re-ANN
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.
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.
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 | — |
Type C Thermocouple (W5Re/W26Re) W26Re-ANN — frequently asked
What is Type C Thermocouple (W5Re/W26Re) W26Re-ANN used for?
Type C Thermocouple (W5Re/W26Re) W26Re-ANN 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) W26Re-ANN?
Type C Thermocouple (W5Re/W26Re) W26Re-ANN has a typical yield strength of 700 MPa (102 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 87% of refractory metal grades. Strength varies by condition: see the 4 listed tempers.
Is Type C Thermocouple (W5Re/W26Re) W26Re-ANN 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) W26Re-ANN 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) W26Re-ANN?
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) W26Re-ANN 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) W26Re-ANN?
Type C Thermocouple (W5Re/W26Re) W26Re-ANN 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.