Tungsten Grade W1 is a commercially pure tungsten grade with a minimum purity of 99.95% W. Produced via powder metallurgy, W1 represents the baseline reference grade for tungsten products and exhibits tungsten’s intrinsic properties in their purest form.
Strengthening & Metallurgical Behavior
W1 tungsten relies on:
✔ Work hardening (rolling, swaging, drawing)
✔ Grain refinement through mechanical deformation
There is no solid-solution strengthening, as W1 contains no intentional alloying elements.
Recrystallization Temperature: ~1200–1400 °C
Above this temperature, rapid grain growth occurs, strength decreases, and post-cooling
brittleness increases. As a result, W1 has lower creep resistance than doped tungsten grades.
Refining & Processing Properties
Tungsten ore → Ammonium Paratungstate (APT)
APT reduction in hydrogen → tungsten powder
Cold isostatic pressing
High-temperature sintering
Mechanical working (rolling, forging, drawing)
Machining: Difficult due to high hardness and low ductility. EDM, grinding, and diamond tooling are commonly used. Hot working is preferred.
Available Forms
Rods & bars
Sheets & plates
Wire & filaments
Discs & slugs
Foils
Precision machined components
Key Characteristics
✔ Extremely high melting point
✔ High density and stiffness
✔ Excellent high-temperature strength
✔ Good thermal and electrical conductivity
✔ Low vapor pressure at high temperature
✔ High thermal shock resistance
✔ Chemically stable in vacuum and inert atmospheres
Limitations
Brittle at room temperature
Poor oxidation resistance above ~400 °C in air
Typical Applications
High Temperature: Furnace elements, heat shields, structural parts
Electronics: Electrical contacts, cathodes, X-ray tube targets
Vacuum & Semiconductor: Evaporation boats, sputtering targets, fixtures
Defense & Radiation: Shielding, counterweights, base penetrator material
Lighting: Specialty and historical lamp filaments
Advantages of Tungsten Grade W1
✔ Maximum purity and predictability
✔ Baseline thermal stability
✔ Excellent electrical and heat conduction
✔ Ideal for vacuum and inert atmospheres
✔ Good dimensional stability at high temperatures
✔ Suitable substrate for coatings and composites
Comparison with Other Tungsten Grades
| Grade | Key Difference |
|---|---|
| W1 | Pure tungsten, baseline properties |
| WP | Similar purity, different impurity limits |
| WK | Potassium-doped, better creep resistance |
| WL | Lanthanum oxide doped, arc stability |
| WRe | Improved ductility and high-temp strength |
Why Choose Tungsten Grade W1?
Choose W1 when chemical purity, intrinsic tungsten performance, and predictable behavior are more important than enhanced creep resistance or ductility. It remains indispensable in vacuum, electrical, and extreme-temperature applications.