Tungsten grades / Tungsten copper
Tungsten Copper
The easiest tungsten material on this site to machine. A porous tungsten skeleton infiltrated with copper, chosen for conductivity rather than density or hardness.
Tungsten copper is made by pressing and sintering a porous tungsten skeleton, then infiltrating it with molten copper, typically 10 to 30% copper by weight. It is written as a ratio, such as W70Cu30 (70% tungsten, 30% copper) or W90Cu10, and the ratio changes density, conductivity and machining behavior, so state it explicitly rather than just writing "tungsten copper" on an RFQ.
| Property | Typical value |
|---|---|
| Density | 14.0 to 17.0 g/cm³ (W70Cu30 to W90Cu10) |
| Hardness | Softer than heavy alloy; varies with ratio, no single typical figure published |
| Magnetic behavior | Non-magnetic |
| Typical tolerance | ±0.01 to ±0.02 mm, tighter by grinding |
Typical density
Density runs 14.0 to 17.0 g/cm³, typical, across the common ratios: higher tungsten content (W90Cu10) sits toward the top of that range, higher copper content (W70Cu30) toward the bottom. This is lower than either pure tungsten or heavy alloy, since density is not why this grade is chosen.
Hardness
Tungsten copper does not have a single widely published typical hardness figure the way heavy alloy and carbide do, because hardness shifts with the tungsten-to-copper ratio and no single value represents the material well. What shops report instead is comparative: it is noticeably softer and more ductile than either heavy alloy grade, and cuts more like a hard brass or bronze than like a refractory metal. If a hardness spec matters for your application, ask your shop or mill for a figure at the specific ratio you are ordering rather than relying on a general number.
Magnetic or non-magnetic
Tungsten copper is non-magnetic. Both constituent metals, tungsten and copper, are non-magnetic on their own, unlike W-Ni-Fe heavy alloy where the iron binder introduces mild magnetism.
How it machines
Tungsten copper is the easiest of the tungsten grades to machine. The copper phase gives it enough ductility to cut more like a hard copper alloy than a brittle refractory metal, producing a cleaner chip and a better as-machined finish than pure tungsten. It turns, mills, drills and taps on standard CNC equipment with carbide tooling, and takes fine detail well, which is exactly why it suits parts like EDM electrodes that need precise geometry. The two things to watch are burr formation, since the copper phase can raise a burr the way copper alloys do, and consistency of the ratio itself, since an uneven tungsten-copper mix in the stock can shift density and conductivity even on a dimensionally correct part.
Typical achievable tolerance
±0.01 to ±0.02 mm is common on turned and milled features, typical, similar to or slightly tighter than tungsten heavy alloy. Critical faces on electrodes, where geometry directly affects the EDM process, are sometimes finished by grinding for the tightest tolerance.
A note on ASTM B777
ASTM B777 covers tungsten heavy alloy, not tungsten copper. It does not apply to this grade. Tungsten copper parts are ordered by ratio (such as W80Cu20) rather than by a B777 class.
Typical applications
- EDM electrodes, where arc erosion resistance combines with conductivity to hold detail through a production run
- Welding electrodes, for the same arc erosion resistance in a different process
- Electrical contacts that carry current and resist wear from repeated switching or arcing
- Heat spreaders, using copper's thermal conductivity alongside tungsten's lower thermal expansion
Sources
Have a tungsten copper part to source? Get matched with a shop that cuts this grade.
Related: tungsten copper machining and pure tungsten vs heavy alloy vs carbide.