Tungsten Alloy Class 1 Tungsten
ASTM B760 Class 1
Class 1 Tungsten is commercially pure, unalloyed tungsten (min ~99.95% W) covered by ASTM B760 Class 1 / UNS R07005, supplied with no potassium-silica doping.
Reference datasheet — Class 1 Tungsten 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.
Values for the SR condition
Class 1 Tungsten tempers and conditions
Class 1 Tungsten is supplied in 5 conditions, soft to hard. SR is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Sintered | Pick for large blocks, crucibles and shielding where full density and ductility are not required and only sintered sizes are available. | 150 | 0 | 280 HB | 26 % IACS | |
Recrystallized / fully annealed | The state reached after high-temperature service or annealing: lowest strength and essentially zero room-temperature ductility — avoid where mechanical loading or handling shock occurs. | 420 | 550 | 0 | 36 HRC | 32 % IACS |
Hot worked | Pick for thick plate and forged shapes where full density and moderate strength are needed but heavy cold work is impossible. | 520 | 700 | 3 | 38 HRC | 30 % IACS |
SRDefault Stress relieved | Default stocked condition: worked then stress relieved (~1000–1300 °C) for dimensional stability with retained fibre structure and best available room-temperature toughness. | 590 | 800 | 2 | 40 HRC | 31 % IACS |
Cold worked | Pick when maximum strength and hardness are wanted (electrodes, tips, thin strip) and residual stress / anisotropy are acceptable. | 950 | 1,200 | 1 | 47 HRC | 30 % IACS |
Supply forms, finishes and certifications
Ways Class 1 Tungsten is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FOIL | Heavily cold rolled foil (< 0.5 mm), hard | Supply form |
WIRE | Drawn wire, as-drawn | Supply form |
GND | Ground / chemically cleaned surface | Surface finish |
What is Class 1 Tungsten?
Class 1 Tungsten is commercially pure, unalloyed tungsten (min ~99.95% W) covered by ASTM B760 Class 1 / UNS R07005, supplied with no potassium-silica doping. Engineers specify it where purity plus electrical and thermal conductivity matter most: 173 W/m·K and 31% IACS, with 590 MPa yield, 800 MPa tensile, 40 HRC and about 2% elongation in the default condition. It is available as sintered blanks, sheet, foil, wire and ground rod, but it is brittle, has a machinability rating of 12 and oxidises rapidly above roughly 500 °C in air. Because it has no sag resistance, use AKS-doped Class 2 tungsten for filament and long-term high-temperature service. Class 1 Tungsten has a density of 19.25 g/cm³ (0.695 lb/in³), heavier than 76% of tungsten alloy grades. It melts at 3,422°C (6,192 °F). Class 1 Tungsten has a yield strength of 590 MPa (85.6 ksi) and a tensile strength of 800 MPa (116 ksi) — weaker than 83% of tungsten alloy grades. Elongation at break is 2% and the elastic modulus is 405 GPa (58.7 Msi).
What is Class 1 Tungsten used for?
- electrical contacts
- heating elements
- X-ray targets
- electron tube components
- high-temperature furnace parts
Limitations
- Low strength — 590 MPa (85.6 ksi), worse than 83% of tungsten alloy grades
Class 1 Tungsten properties
Typical room-temperature values for Class 1 Tungsten-SR; bars are the position among tungsten alloy grades.
Physical3
Class 1 Tungsten has a density of 19.25 g/cm³ (0.695 lb/in³), heavier than 76% of tungsten alloy grades. It melts at 3,422°C (6,192 °F).
Mechanical16
Class 1 Tungsten has a yield strength of 590 MPa (85.6 ksi) and a tensile strength of 800 MPa (116 ksi) — weaker than 83% of tungsten alloy grades. Elongation at break is 2% and the elastic modulus is 405 GPa (58.7 Msi).
Thermal6
Class 1 Tungsten is rated for continuous service to 500°C (932 °F). It conducts heat at 173 W/m·K (100 BTU/hr·ft·°F), better than 88% of tungsten alloy grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).
Electrical3
Class 1 Tungsten conducts electricity at 31 % IACS, better than 83% of tungsten alloy grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 79% of tungsten alloy grades.
Sustainability4
Producing a kilogram of Class 1 Tungsten takes about 400 MJ of energy and emits 27 kg of CO₂ — more than 74% of tungsten alloy grades. Typical recycled content is 30%.
Manufacturability8
Class 1 Tungsten's machinability is not recommended (12/100, better than 67% of tungsten alloy grades); weldability not recommended (12/100); formability not recommended (8/100).
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 tungsten alloy family
Yield strength against density for every tungsten alloy grade FabDigit runs. Class 1 Tungsten is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Class 1 Tungsten
Is Class 1 Tungsten easy to machine?
Treat as a brittle refractory: prefer grinding, wire/sinker EDM and diamond or negative-rake carbide tooling with rigid setups, low speed and flood coolant; preheating 200–400 °C reduces chipping in turning.
Can Class 1 Tungsten be welded?
Fusion welding embrittles the weld through recrystallization — use electron-beam or laser welding in high vacuum on clean, low-oxygen material with preheat, or avoid welding entirely in favour of vacuum brazing and mechanical joints.
Can Class 1 Tungsten be formed, bent or molded?
Only hot forming works: bend, roll or spin above ~400 °C (thicker sections 800–1200 °C) with generous radii; cold bending of stress-relieved sheet cracks except in very thin foil.
Class 1 Tungsten 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.
| Element | Spec limit (wt %) |
|---|---|
| Motypical impurity limit | ≤ 0.02 |
| Fetypical impurity limit | ≤ 0.01 |
| Nitypical impurity limit | ≤ 0.01 |
| Ctypical impurity limit | ≤ 0 |
| Otypical impurity limit | ≤ 0 |
| Ntypical impurity limit | ≤ 0 |
| Htypical impurity limit | ≤ 5×10⁻⁴ |
| Sitypical impurity limit | ≤ 0 |
| Altypical impurity limit | ≤ 0 |
| Catypical impurity limit | ≤ 0 |
| Crtypical impurity limit | ≤ 0 |
| Cutypical impurity limit | ≤ 0 |
| Mgtypical impurity limit | ≤ 0 |
| Kundoped grade — potassium deliberately kept low | ≤ 0 |
| Wunalloyed, undoped (no K/Al/Si dopant additions) | ≥ 99.95 (balance) |
What surface finishes work on Class 1 Tungsten?
Grind/lap then chemically clean (alkaline peroxide or HF/HNO₃ etch) for vacuum use; for service above ~500 °C in air apply silicide, Ir/Pt or CVD coatings, and Ni/Cu plating is used to aid brazing and soldering.
Equivalent designations
Standards and trade names that resolve to Tungsten Alloy Class 1 Tungsten in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B760 Class 1
- Similar grades
- R07005
How much does Class 1 Tungsten cost?
Class 1 Tungsten is a high-cost tungsten alloy ($$$$), 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.
Class 1 Tungsten — frequently asked
What is Class 1 Tungsten used for?
Class 1 Tungsten is typically used for electrical contacts, heating elements, X-ray targets, electron tube components and high-temperature furnace parts. In short: highest-purity tungsten class; best conductivity, 31% IACS; no sag resistance.
What is the yield strength of Class 1 Tungsten?
Class 1 Tungsten has a typical yield strength of 590 MPa (85.6 ksi) and a tensile strength of 800 MPa (116 ksi) — weaker than 83% of tungsten alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Class 1 Tungsten easy to machine?
Not especially — machinability is rated not recommended (12/100, better than 67% of tungsten alloy grades). Treat as a brittle refractory: prefer grinding, wire/sinker EDM and diamond or negative-rake carbide tooling with rigid setups, low speed and flood coolant; preheating 200–400 °C reduces chipping in turning.
Can Class 1 Tungsten be welded?
Not readily — weldability is rated not recommended (12/100). Fusion welding embrittles the weld through recrystallization — use electron-beam or laser welding in high vacuum on clean, low-oxygen material with preheat, or avoid welding entirely in favour of vacuum brazing and mechanical joints.
What surface finishes work on Class 1 Tungsten?
Grind/lap then chemically clean (alkaline peroxide or HF/HNO₃ etch) for vacuum use; for service above ~500 °C in air apply silicide, Ir/Pt or CVD coatings, and Ni/Cu plating is used to aid brazing and soldering.
Can Class 1 Tungsten be formed, bent or molded?
Only hot forming works: bend, roll or spin above ~400 °C (thicker sections 800–1200 °C) with generous radii; cold bending of stress-relieved sheet cracks except in very thin foil.
What is the maximum service temperature of Class 1 Tungsten?
Class 1 Tungsten is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Class 1 Tungsten-SR and Class 1 Tungsten-CW?
SR is the default condition — default stocked condition: worked then stress relieved (~1000–1300 °C) for dimensional stability with retained fibre structure and best available room-temperature toughness. CW: pick when maximum strength and hardness are wanted (electrodes, tips, thin strip) and residual stress / anisotropy are acceptable. Yield strength is 590 MPa in SR versus 950 MPa in CW.
How much does Class 1 Tungsten cost?
Class 1 Tungsten is a high-cost tungsten alloy ($$$$), 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 B760 — Standard Specification for Tungsten Plate, Sheet, and Foil — ASTM International (2022)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Refractory Metals) — ASM International (1990)
- Tungsten — material properties and product data — Plansee SE (2023)
- Pure tungsten semi-finished products datasheet — H.C. Starck / Metallwerk Plansee-type supplier data (2022)
- CRC Handbook of Chemistry and Physics (thermophysical data for W) — CRC Press (2020)
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.