Tungsten Wire Products

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What is the properties of tungsten wires?

The properties of tungsten wires, incuding the dimension and the tolerance of tungsten wires, Tensile Strength, Straightness, Splits, Quality and Finish and Spooling.

Dinmension and Tolerance

Tungsten wire tolerances and tungsten wire dimensions,for example tungsten wire diameters, are generally expressed in terms of mm(or inches). For thin wires from 0.02mm up to 0.5mm in diameter, the diameter of tungsten wire is measured by weight per unit length. That is, the weight expressed in mg of a 200 mm length of tungsten wire.

The standard diameter tolerance is 3% of the weight measurement. Closer tolerances are available, depending upon the application for tungsten wire product.

For thicker tungsten wires from 0.5mm up to 6.5mm in diameter, the mm measurements are used. The tolerances are expressed as a percentage of the diameter. Standard tolerance is 1.5%.

Tensile Strength
Tensile strength for tungsten wire is usually expressed in grams per milligram weight of a 200mm (or) g/mg/200mm. The normal range of values is from 40 to 110 grams. In general, as tensile strength increases, wire straightness decreases.

Straightness Tungsten wire can be straightened via mechanical or heat treating processes. Typically, the measure of the straightness of a tungsten wire is obtained by cutting a ten inch long piece of wire and allowing it to lie on a flat clean surface. The maximum deviation from a straight line along its length is the quantitative measure of its straightness. In general, as the degree of straightness increases, tensile strength decreases.

Splits Longitudinal cracks with a depth of more than 15% of the tungsten wire diameter are called splits. Tungsten wire is checked for splits with an eddy current split detector. The split level for a given length of tungsten wire is typically less than 5%.

Quality and Finish Tungsten wire is free of scratches, kinks and distortions insofar as they are harmful to the intended end use of the product. Surface finish is supplied in the black, as drawn condition, where drawing lubricants and oxides are retained on the surface, or in the cleaned condition by firing in hydrogen or electrochemical etching.

Spooling

Tungsten wire is spooled on clean, defect free spools. For very large diameters, tungsten wire is self coiled. Spools are level filled without piling near flanges. The outer end of the tungsten wire is properly marked and attached securely to the spool or self coil.