Types of Tungsten Wire

• Pure Tungsten Wire: Produced for re-straightening into rod products and applications with low alkali content requirements. Produced in sizes above .02 inches in diameter.
• WK (K-Al-Si Doped) Tungsten Wire: Doped with trace amounts of potassium, causing the wire to display an elongated interlocking grain structure, exhibiting non-sag properties. Used for lamp filament and wire filament applications. Produced in sizes from .001 to .250 inches in diameter.

Dimensions and Tolerances

• For thin wires (.001 to .02 inches), diameter is measured by weight per unit length with a standard tolerance of ±3%.
• For thicker wires (.02 to .25 inches), inch or mil measurements are used with a standard tolerance of ±1.5%.

• To calculate the diameter, the equation is:

     Diameter (in mils) = .71746 x square root (mg weight/200 mm length)

• Other Useful Equations:

     meters/kilogram = 102950 / (diameter in mils)2

     mg/200 mm = 1.9427 x (diameter in mils)2

Out of Roundness

• Out of Roundness = (Maximum Diameter – Minimum Diameter / Maximum Diameter) x 100

Splits

• Longitudinal cracks exceeding 15% of the wire diameter are termed splits.
• Splits are detected using an eddy current split detector.
• The acceptable split level for a specific wire length is generally below 5%.

Tensile Strength and Straightness

• Tensile strength is expressed in grams per milligram weight of a 200mm length, ranging from 40 to 110 grams.
• Straightness is crucial and can be adjusted to meet specific customer requirements.
• As tensile strength increases, wire straightness decreases.
• The wire is finished in either an un-straightened or as-drawn condition.
• The wire can either be straightened by a mechanical or heat-treating process.

Quality and Finish

• Our tungsten wires are free of scratches, kinks, and deformities, ensuring optimal performance.
• Surface finish options include a natural black finish preserving drawing lubricants and oxides on the surface or a clean look achieved through firing in hydrogen or electrochemical etching.

Spooling

• Wires are spooled on clean, defect-free spools or coiled for larger diameters.
• Spools are level-filled without piling near flanges.
• The wire’s outer end is marked precisely and securely fastened to the spool or coiled.

Customization:

• T&D Materials produces wire products according to internal standards, with the flexibility to adjust specifications to meet unique customer requirements.

Applications:

• Incandescent Lamp Filaments: Ideal for coiled incandescent lamp filaments.
• Power Tubes: Serves as cathode and support structures for power tubes.
• High-Temperature Furnaces: Essential for heating elements in high-temperature furnaces.
• Metalizing Processes: Used as evaporation sources in metalizing processes.
• Glass-to-Metal Seal Lead Parts: Thicker wire sizes are employed for glass-to-metal seal lead parts in lighting and electronic industries.