Types of Tungsten for Machined Parts
"Tungsten" covers five different materials in a machine shop. They share a name and a heavy grain, but the binder changes the density, the magnetism and how the part cuts. Values below are typical.
| Type | Composition | Density, g/cm³ | Magnetism | Typical use |
|---|---|---|---|---|
| Pure tungsten | 99.95% W | About 19.3 | Non-magnetic | Furnace hot zones, crucibles, electrodes |
| Heavy alloy W-Ni-Fe | 90 to 97% W, nickel-iron binder | 17.0 to 18.5 | Mildly magnetic | Shielding, counterweights, ballast |
| Heavy alloy W-Ni-Cu | 90 to 97% W, nickel-copper binder | 17.0 to 18.0 | Effectively non-magnetic | Parts near MRI, sensors, electron beams |
| Tungsten copper | W70Cu30 to W90Cu10 | 14.0 to 17.0 | Non-magnetic | EDM electrodes, contacts, heat sinks |
| Tungsten carbide | WC grains in a cobalt binder | 14.5 to 15.6 | Mildly magnetic | Wear parts, dies, cutting tools |
For comparison, steel is 7.9 g/cm³ and lead is 11.3 g/cm³. Each type links to a full grade datasheet.
Pure tungsten
Unalloyed tungsten has the highest melting point of any metal and holds its shape in furnace hot zones and vacuum systems. It is brittle at room temperature, so edges chip and thin walls crack. Fine features are often ground or wire EDM cut. Read the pure tungsten furnace components guide and how it compares with tantalum and molybdenum.
Tungsten heavy alloy
Heavy alloy is tungsten grains held in a nickel-based binder, 90 to 97% tungsten by weight. The binder makes it practical to machine, so it is the grade most shops mean when a buyer asks for machined tungsten. Two binders matter:
- W-Ni-Fe has a nickel-iron binder. It is mildly magnetic and the default for shielding and counterweights.
- W-Ni-Cu has a nickel-copper binder. It is effectively non-magnetic, for parts near MRI equipment or sensors. See the non-magnetic tungsten parts guide.
Mills supply heavy alloy to ASTM B777, which sets four classes by tungsten content and density. See ASTM B777 classes explained and the trade names such as Densalloy and Anviloy.
Tungsten copper
A porous tungsten skeleton infiltrated with copper. It combines tungsten's arc and wear resistance with copper's conductivity, so it is used for EDM electrodes, electrical contacts and heat sinks. It cuts cleanly, closer to a hard bronze. See the tungsten copper machining guide.
Tungsten carbide
Tungsten carbide is a different material from the metal. Carbide grains are sintered in a cobalt binder into a very hard cermet. Some buyers call it "tungsten steel," which can cause confusion on an RFQ. It is too hard to mill after sintering, so it is ground and wire EDM cut. See carbide versus heavy alloy machining and grinding versus machining carbide.
Tungsten forms and blanks
Type is only half the specification. The same grade ships as a sintered blank, a wrought bar or plate, or a near-net pressed shape, and the choice affects cost and lead time. See sintered versus wrought blanks, standard bar and plate sizes and metric versus imperial bar stock.
How to choose a type
- Maximum mass or shielding in a small space: heavy alloy W-Ni-Fe
- Very high service temperature: pure tungsten
- Dense but non-magnetic: heavy alloy W-Ni-Cu
- Arc erosion or heat spreading: tungsten copper
- Hardness and wear: tungsten carbide
The full side-by-side is in the grade comparison guide. For where each type is used, see applications, and for how each is cut, see machining processes.
Frequently asked questions
What are the main types of tungsten?
For machined parts there are five: pure tungsten, tungsten heavy alloy W-Ni-Fe, tungsten heavy alloy W-Ni-Cu, tungsten copper and tungsten carbide. They differ in binder, density, magnetism and how they cut.
Is tungsten carbide the same as tungsten?
No. Tungsten carbide is a sintered cermet of tungsten carbide grains in a cobalt binder. It is hard and wear resistant but lighter than pure tungsten or heavy alloy, and it is ground rather than milled.
Which type is the densest?
Pure tungsten, at about 19.3 g/cm³, typical. Heavy alloy follows at 17.0 to 18.5 g/cm³. Tungsten copper runs 14.0 to 17.0 and tungsten carbide 14.5 to 15.6.
Which type is non-magnetic?
Pure tungsten, tungsten copper and W-Ni-Cu heavy alloy. Standard W-Ni-Fe heavy alloy and tungsten carbide with a cobalt binder are mildly magnetic.
What is the easiest tungsten type to machine?
Heavy alloy and tungsten copper cut most like conventional metals. Pure tungsten is brittle and carbide is extremely hard, so both need more care and often grinding or wire EDM.