Pure Tungsten and Tungsten Heavy Alloy Scrap Specification

Three materials in this family are routinely conflated, and they are not equivalent. Pure tungsten is the elemental metal: tungsten atoms with no carbon compound structure and no metallic binder phase. Tungsten heavy alloy is a two-phase composite in which tungsten grains are held in a ductile metallic matrix, most commonly nickel with iron or nickel with copper, produced by liquid-phase sintering. Cemented carbide (WC-Co) is a compound of tungsten and carbon cemented by cobalt, and it is a different chemical material from either of the above.

The difference is not academic. Pure tungsten and heavy alloy contain tungsten in metallic form; cemented carbide contains tungsten chemically bound as a carbide. That governs which processors can accept the material and by which route it re-enters the supply chain. A lot of heavy alloy sent to a carbide processor as 'tungsten scrap' is a mis-described lot, and a mixed drum containing all three is worse than either.

Pure tungsten scrap typically arises from lighting and electronics manufacturing, welding electrodes, furnace and vacuum equipment, sputtering targets and high-temperature components. Heavy alloy arises from balance weights, radiation shielding, vibration-damping tooling, aerospace and defence components and kinetic mass applications. The applications tell you what the physical presentation is likely to be, and physical presentation is one of the more useful identification aids in this stream.

Heavy alloy composition varies by designation, matrix system and manufacturer, and used articles rarely carry legible marking. No composition is stated here in advance; where the matrix system or tungsten content matters commercially, it must be established by an agreed analysis and recorded contractually.

The two sub-streams present quite differently and are best described separately at enquiry stage.

Density does not separate these materials usefully — all three are heavy — so identification relies on mechanical behaviour and form. Cemented carbide is brittle and chips; it shows a fine, uniform grey fracture and cannot be machined with conventional tooling. Tungsten heavy alloy is comparatively tough and can be machined and turned, which is precisely why counterweights are made from it; a machined thread, a turned surface or a drilled hole on a very heavy grey part is a strong indicator of heavy alloy rather than carbide. Pure tungsten in thin section such as wire or foil is workable, while thick pure tungsten sections are brittle at room temperature.

Form is the second indicator. Wire, foil, sheet, electrodes and machined mill forms are metal-industry presentations; sintered tool geometry such as inserts, buttons and dies is carbide. Weld-tinted electrode tips, drawn wire spools and rolled sheet edges do not occur in cemented carbide.

Two specific cautions apply. Thoriated welding electrodes contain a low level of thorium oxide and are subject to handling and shipment rules in some jurisdictions; where electrodes are offered, the type should be stated. And sputtering targets are often bonded to a copper or aluminium backing plate, so the tungsten fraction of the delivered weight is not the whole article.

Because these materials follow different recovery routes from carbide, the first evaluation question is always which material is actually being offered, and the second is how consistent the population is.

Contamination in this stream is mostly attached foreign metal and surface treatment rather than dirt, and the most costly issue by far is cross-contamination between the three tungsten-bearing families.

Segregation is the whole discipline in this stream: pure tungsten, heavy alloy and any carbide must be packed as separate, individually labelled fractions. A single mixed drum forces a sort at destination and undermines the description of the entire lot.

Beyond that, packing follows the physical form. Bulky machined counterweights, thin foil and fine wire each need different handling, and heavy single pieces need to be secured so they cannot shift.

Accurate material description matters more here than anywhere else in the tungsten family, because the description determines both the customs treatment and which processor the cargo can be routed to on arrival. Packing lists should identify each fraction by material family, not by the generic phrase 'tungsten scrap'.

Certain items in this stream carry additional considerations: thoriated welding electrodes are regulated in some jurisdictions, and components from shielding, aerospace or defence-adjacent applications may attract provenance or end-use documentation requirements. These must be identified before shipment and confirmed for the specific trade lane.

Weight distribution in the container is a practical concern given the density of the articles, and heavy single pieces must be positioned and secured accordingly.

Screening in this stream is used first to answer a categorical question — is this piece elemental tungsten, heavy alloy, or carbide — before it is used to say anything quantitative. That categorical answer is usually clear from the elemental fingerprint: heavy alloy shows nickel with iron or copper alongside tungsten, while pure tungsten shows tungsten with minimal alloying elements. Carbon is not measurable by XRF, so cemented carbide is inferred from the cobalt signature and mechanical behaviour rather than read directly.

Quantitative statements need more than a screening reading. Plating, coatings, oxidation from high-temperature service and bonded backing plates all distort surface results, and the tungsten fraction of an assembly is not the same as the composition of the tungsten part within it.

Tungsten metal scrap and tungsten alloy scrap can be described and classified differently from cemented carbide scrap. The applicable classification depends on the actual composition, the physical form of the goods as shipped, whether the article is an assembly with non-tungsten components, the destination country and the interpretation of the competent customs authority there.

Some items in this family attract requirements beyond tariff classification — thoriated welding electrodes and components originating from shielding or defence-adjacent applications are the common examples — and these can differ sharply between jurisdictions.

Nautica does not assign a definitive tariff code in advance for this stream. Importers should confirm classification, duty treatment, licensing and any regulated-item requirement with their customs broker or the competent customs authority before contracting.