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Refractory Metal Type C Thermocouple (W5Re/W26Re) W26Re-AD

Supply condition

ASTM E230 Type C · ISO 27043 Type C

W26Re-AD = 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.

High cost $$$$

Values for the W26Re-AD 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 datasheetBest forYield MPaTensile MPaElong. %HardnessConductivity
W-5%Re positive leg
Softer, drift-stabilised positive leg for tight-radius routing and for sensors that must be pre-aged before calibration.55080014420 HV14.4 % IACS
W-26%Re negative leg
Annealed negative leg for maximum room-temperature ductility during coiling, welding and sheath insertion.7001,00018480 HV6.2 % 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.1,6501,9003580 HV14.4 % IACS
W26Re-ADThis page
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.1,8502,2005620 HV6.2 % IACS

What is Type C Thermocouple (W5Re/W26Re) W26Re-AD?

Type C Thermocouple (W5Re/W26Re) W26Re-AD is Type C Thermocouple (W5Re/W26Re) supplied in the W26Re-AD condition — negative leg as supplied on spool; the rhenium ductilising effect keeps it bendable at room temperature despite very high strength. Type C Thermocouple (W5Re/W26Re) W26Re-AD has a yield strength of 1,850 MPa (268 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 101% of refractory metal grades. Elongation at break is 5% and the elastic modulus is 388 GPa (56.3 Msi). Type C Thermocouple (W5Re/W26Re) W26Re-AD has a density of 19.7 g/cm³ (0.712 lb/in³), heavier than 97% of refractory metal grades. It melts at 3,120°C (5,648 °F).

Advantages

  • High strength — 1,850 MPa (268 ksi), better than 101% of refractory metal grades
  • High service temperature — 2,320°C (4,208 °F), better than 98% of refractory metal grades
  • Stiff — 388 GPa (56.3 Msi), better than 93% 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 — 7/100, worse than 94% of refractory metal grades
  • Limited ductility — 5%, worse than 78% of refractory metal grades

Type C Thermocouple (W5Re/W26Re) W26Re-AD properties

Typical room-temperature values for Type C Thermocouple (W5Re/W26Re) W26Re-AD; 15 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-AD has a density of 19.7 g/cm³ (0.712 lb/in³), heavier than 97% of refractory metal grades. It melts at 3,120°C (5,648 °F).

Density19.7 g/cm³0.71 lb/in³
Melting Point (Solidus)3,120°C5,648 °F
Liquidus Temperature3,250°C5,882 °F

Mechanical8

Type C Thermocouple (W5Re/W26Re) W26Re-AD has a yield strength of 1,850 MPa (268 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 101% of refractory metal grades. Elongation at break is 5% and the elastic modulus is 388 GPa (56.3 Msi).

Elastic (Young's) Modulus388 GPa56.3 Msi
Shear Modulus152 GPa22 Msi
Bulk Modulus305 GPa44.2 Msi
Poisson's Ratio0.29
Tensile Strength (Ultimate)2,200 MPa319 ksi
Yield Strength (0.2% offset)1,850 MPa268 ksi
Elongation at Break5%
Hardness, Vickers620 HV

Thermal6

Type C Thermocouple (W5Re/W26Re) W26Re-AD is rated for continuous service to 2,320°C (4,208 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 56% of refractory metal grades. Thermal expansion is 4.9 µm/m·K (2.72 µin/in·°F).

Thermal Conductivity45 W/m·K26 BTU/hr·ft·°F
Specific Heat Capacity142 J/kg·K0.03 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)4.9 µm/m·K2.7 µin/in·°F
Latent Heat of Fusion275 J/g118 BTU/lb
Max Service Temperature (continuous)2,320°C4,208 °F
Min Service Temperature0°C32 °F

Electrical3

Type C Thermocouple (W5Re/W26Re) W26Re-AD conducts electricity at 6.2 % IACS, better than 51% of refractory metal grades.

Electrical Conductivity6.2 % IACS
Electrical Resistivity2.8×10⁻⁷ Ω·m11 µΩ·in
Magnetic Responsenon-magnetic (paramagnetic; μr ≈ 1)

Chemical & Environmental2

Corrosion resistance is fair (35/100), worse than 99% of refractory metal grades.

Corrosion ResistanceFair35/100
Chemical Resistance SummaryInert to most molten metals, glasses and vacuum/argon environments; oxidizes catastrophically (volatile WO3) above ~500 °C in air or in any oxygen/water-vapour leak; embrittled by carbon, nitrogen and by hot HF/HNO3 mixtures and molten alkalis; attacked by fluorine and chlorine at temperature.

Sustainability4

Producing a kilogram of Type C Thermocouple (W5Re/W26Re) W26Re-AD takes about 500 MJ of energy and emits 35 kg of CO₂ — less than 70% of refractory metal grades. Typical recycled content is 10%.

Embodied Energy (primary production)500 MJ/kg214,962 BTU/lb
Embodied Carbon (primary production)35 kg CO₂/kg
Embodied Water350 L/kg41.9 gal/lb
Typical Recycled Content10%

Manufacturability8

Type C Thermocouple (W5Re/W26Re) W26Re-AD's machinability is not recommended (7/100, worse than 94% of refractory metal grades); weldability poor (30/100); formability poor (25/100).

MachinabilityNot recommended7/100
Machinability Rating (AISI 1212 = 100 %)5%
WeldabilityPoor30/100
Formability (cold)Poor25/100
CastabilityNot recommended10/100
Brazeability / SolderabilityFair45/100
PolishabilityGood60/100
Anodizing Responsen/a — refractory metal wire, not anodized; surface is chemically cleaned or electropolished instead

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-AD

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.

ElementSpec limit (wt %)Nominal
Renegative (–) leg W-26Re24.5 – 2726
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 legsbalance—

Type C Thermocouple (W5Re/W26Re) W26Re-AD — frequently asked

What is Type C Thermocouple (W5Re/W26Re) W26Re-AD used for?

Type C Thermocouple (W5Re/W26Re) W26Re-AD 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-AD?

Type C Thermocouple (W5Re/W26Re) W26Re-AD has a typical yield strength of 1,850 MPa (268 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 101% of refractory metal grades. Strength varies by condition: see the 4 listed tempers.

Is Type C Thermocouple (W5Re/W26Re) W26Re-AD easy to machine?

Not especially — machinability is rated not recommended (7/100, worse than 94% 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-AD 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-AD?

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-AD 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-AD?

Type C Thermocouple (W5Re/W26Re) W26Re-AD 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

  1. ASTM E988 — Temperature-EMF Tables for Tungsten-Rhenium Thermocouples — ASTM International (2019)
  2. ASTM E230/E230M — Standard Specification and Temperature-EMF Tables for Standardized Thermocouples — ASTM International (2023)
  3. ASTM E1751/E1751M — Guide for Temperature-EMF Tables for Non-Letter-Designated Thermocouple Combinations — ASTM International (2020)
  4. ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (refractory metals) — ASM International (1990)
  5. ASM Handbook Vol. 3 — Alloy Phase Diagrams (W-Re system) — ASM International (2016)
  6. Tungsten-Rhenium alloy wire and thermocouple data — Rhenium Alloys Inc. / Plansee (2023)
  7. 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.