# Tungsten

Selecting pure tungsten by product, condition and atmosphere, with distinctions from heavy alloys and carbide and bounded fabrication evidence.

Reviewed: 2026-11-01

Tags: materials, refractory-metals, specialty-metals

## Identity and product family

Elmet lists tungsten as **stable in air or oxygen at 20°C** and says **oxidation starts at 400°C** in that atmosphere. Its table separately lists **oxidation in steam above 700°C**. Use these observations to screen the environment and obtain time-dependent evidence for continuous service. [Elmet tungsten reaction table](https://www.elmettechnologies.com/wp-content/uploads/2011/12/Tungsten-Chemical-Interactions-2017.pdf)

**Tungsten**, symbol **W**, is a refractory metal. Elmet distinguishes its pure tungsten from potassium-doped tungsten, lanthanated tungsten and tungsten heavy alloys. Its manufacturing route presses and sinters powder, followed by rolling, swaging or drawing into mill products. Preserve the actual product and route when selecting material. [Elmet tungsten products](https://www.elmettechnologies.com/tungsten/)

Tungsten carbide is another material system. Plansee describes hard metal as a tungsten-carbide/cobalt composite. A carbide cutting insert, pure tungsten plate and a tungsten heavy-alloy counterweight therefore need separate specifications and property records. [Plansee Group: tungsten and hard metal](https://plansee-group.com/en/company/tungsten)

## Product specification and certification

**ASTM B760-07(2023)** covers **wrought unalloyed tungsten plate, sheet and foil**. Its abstract describes consolidation by powder metallurgy or vacuum-arc casting and lists hot-rolled, stress-relieved and cold-rolled conditions. It does not provide a universal specification for every tungsten alloy, wire or printed part. Its inch-pound values control; parenthetical SI values are informational conversions. [ASTM B760 scope and abstract](https://store.astm.org/standards/b760)

Elmet's pure rod/wire/plate/sheet document gives **99.95% minimum W, excluding gases**, alongside individual impurity limits. It explicitly says that finished-part chemical analysis and mechanical properties are not routinely evaluated per ASTM requirements; its cited ASTM methods and specifications guide process control. A general sheet is therefore insufficient evidence of order-specific finished-part testing. [Elmet pure tungsten material sheet](https://www.elmettechnologies.com/wp-content/uploads/2011/12/Tungsten-Rod-Wire-Plate-Sheet-Products-Data-Sheet-2017.pdf)

Retain the certificate and agreed testing with the actual delivered lot. Resolve exclusions such as gases, impurity accounting and sampling before comparing purity claims. Do not turn a nominal purity description into a mechanical-property guarantee.

## Physical properties and a bounded mass estimate

Elmet lists density **19.25 g/cm³** and melting point **3,420°C** in its general tungsten facts. These are selection inputs, not a dimensional tolerance or continuous-use rating. [Elmet physical overview](https://www.elmettechnologies.com/tungsten/)

An ideal solid 20 × 20 × 10 mm block has volume **4 cm³**. Using the listed density gives an estimated mass of **77 g**. This original calculation excludes porosity, composition variation, tolerances and attached hardware. For a real component, use its finished geometry and an appropriate delivered-material density.

Do not assign one tensile or ductility value to all tungsten forms. Elmet identifies grain size, strength, hardness and ductility as properties it tailors through manufacture. Match any property dataset to product condition, orientation, temperature and test method. [Elmet manufacturing and property control](https://www.elmettechnologies.com/tungsten/)

## Atmosphere and chemical exposure

Elmet's chemical-reaction table separates **air/oxygen at 20°C, listed as stable**, from **400°C, where oxidation starts**. It also lists steam above **700°C** as oxidizing. These entries make atmosphere part of selection; they are not service-life curves or a guarantee of zero reaction below a threshold. [Elmet chemical reactions of tungsten](https://www.elmettechnologies.com/wp-content/uploads/2011/12/Tungsten-Chemical-Interactions-2017.pdf)

The same table distinguishes **10% aqueous sodium hydroxide at 20°C**, listed as stable, from **molten sodium/potassium hydroxide**, listed as rapidly attacking. Preserve concentration, phase and temperature instead of reducing the evidence to “alkali resistant.” The sheet does not specify a complete duration or corrosion-rate protocol. [Elmet chemical-interaction table](https://www.elmettechnologies.com/wp-content/uploads/2011/12/Tungsten-Chemical-Interactions-2017.pdf)

For a furnace or process component, document gas composition, impurities, pressure, temperature cycle and shutdown exposure. Assess cleaning and upset conditions as well as steady operation. Specify acceptable mass loss, dimensional change or contamination and seek representative testing when the published evidence does not match the duty.

## Fabrication and additive-manufacturing evidence

A 2025 study used powderless single laser tracks on pure tungsten plates in three processing setups with different oxygen activities. It identified solidification cracking as a feasible mechanism in addition to ductile-to-brittle-transition cracking; synchrotron observations and thermal calculations addressed when cracks formed. These experiments do not supply a guaranteed crack threshold or universal additive recipe. [Karra et al.: solidification cracking of laser-melted commercial-purity tungsten](https://www.nature.com/articles/s41598-025-24742-w)

For machining or forming, establish stock history, tool contact, feature geometry, temperature and permitted surface damage. Qualify the process on representative material. For a printed or laser-processed part, retain feedstock chemistry, machine, parameters, thermal history, orientation and defect inspection. A nominal density or intact external surface cannot establish the condition of inaccessible regions.

For a joined assembly, qualify the joint and its thermal history separately. Define acceptance for cracking, distortion, leak integrity or contamination as the application requires. A base-material certificate cannot demonstrate the completed joint's performance.

## Processing safety and release

Elmet's tungsten SDS distinguishes solid products from generated chips, fines and dust. It warns that fine material can ignite and that combustibility depends on particle size, moisture and processing conditions. It calls for collection at the point of dust generation and controls appropriate to potentially reactive fine powder. [Elmet tungsten SDS, sections 2 and 8](https://www.elmettechnologies.com/wp-content/uploads/2023/01/S-17-003-Rev-Elmet_Tungsten_SDS_GHS-2016.pdf)

Obtain the delivered product's current safety information and assess the material produced by the actual operation. Keep pure tungsten, binder-containing heavy alloys and carbide-processing residues distinct. Use a facility procedure covering collection, storage, cleaning and fire response; this article is not a workshop operating procedure.

At release, connect the ordered product, lot, composition, condition, dimensions, processing history and test results. Resolve substitutions against the complete record, including atmosphere and service conditions. An application list identifies candidates for investigation and does not qualify the finished component.

## Source versions

ASTM's publisher identifies **B760-07(2023)**. Elmet's pure-product sheet prints **rv-10/05** and cites historical ASTM editions; its 2017 filename does not establish a new revision. The chemical-reaction sheet and live product pages do not establish clear technical revision dates in the inspected text. The research paper was published **28 November 2025**. The SDS remains separately scoped safety information. Review date: **2026-11-01, America/Los_Angeles**.

[Grades, tempers and conditions](../grades-tempers-and-conditions.md)