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What is tungsten carbide? Grains, binder, grades and uses
By CarbideBuyerUSA · Updated
The machine shop answer to what is tungsten carbide is cemented carbide: hard grains of tungsten carbide locked in a metal binder, usually cobalt, then pressed and sintered into inserts, end mills, rods, dies and mining bits. This guide covers what goes into it, how grades differ and why worn pieces go to recycling.
What tungsten carbide is made of
Tungsten carbide on its own is a compound of tungsten and carbon. ITIA, the International Tungsten Industry Association, puts stoichiometric tungsten carbide at 6.13% carbon by weight. That powder is the main ingredient of cemented carbide.
Cemented carbide, also known as hardmetal or just carbide, bonds very hard carbide grains with a softer, tougher metal: cobalt, nickel or iron. In a typical grade, ITIA says, tungsten carbide particles of 1 to 2 microns are embedded in a cobalt alloy matrix.
ITIA describes the classic mix this way: "A typical example of such an alloy would be 90% tungsten carbide with 10% cobalt, a so-called straight grade." Other grades add titanium or tantalum carbide.
How a carbide part is made
The powders are milled into one mix and shaped; inserts are die pressed straight to final shape. Sintering closes the pores, and ITIA puts the lateral shrinkage at 17 to 24%. An end mill's final shape is ground afterward with diamond tools.
Sources: ITIA: Properties and intermediates; ITIA: Cemented carbides, a success story (newsletter, June 2010); ITIA: Applications and markets; NTP Report on Carcinogens, 13th edition: Cobalt-tungsten carbide powders and hard metals.
The binder: cobalt, nickel and how much of it
Cobalt does the binding in most grades. A Lawrence Livermore manuscript on OSTI calls it the most common binder for cemented tungsten carbide.
The binder share moves inside a known band. A background document from the National Toxicology Program (NTP) says commercial cobalt-tungsten carbide generally runs from 3% to 16% cobalt. Some special grades go higher; one ITIA example carries 20% cobalt.
Binder trades hardness for toughness. ITIA says the hardness comes from the tungsten carbide and the toughness from the cobalt.
Nickel turns up where corrosion counts. For wear parts, ITIA says, nickel-chromium, iron-nickel-cobalt and pure nickel binders are taken into consideration when corrosion is a relevant factor.
The binder share also splits a pound of scrap into its metals. Enter a weight and a cobalt percentage in the carbide content calculator and it breaks the lot into tungsten, carbon and cobalt.
Sources: OSTI: Lawrence Livermore manuscript on cobalt binders in WC composites (2018); ITIA: Cemented carbides, a success story (newsletter, June 2010); NTP background document: Cobalt-tungsten carbide hard metals (2009); ITIA: Applications and markets.
Density and hardness, in numbers
Carbide is heavy for its size, and the binder decides how heavy. Figures in grams per cubic centimeter:
| Material | Density (g/cm³) | Source |
|---|---|---|
| Pure tungsten metal | 19.30 | NIST |
| Tungsten carbide, the compound | 15.6 | NTP |
| Binderless tungsten carbide (theoretical) | 15.64 | OSTI, 2022 |
| Carbide grade with 3.7% cobalt | 15.17 | OSTI, 2023 |
| Carbide grade with 6.0% cobalt | 14.91 | OSTI, 2023 |
| WC-Co part with about 19% cobalt | 13.1 | Oak Ridge (OSTI) |
| Pure cobalt | 8.92 | NTP |
| Pure iron | 7.874 | NIST |
Cobalt weighs a little over half as much as tungsten carbide, so each added point of binder pulls the density down. A grade near 15 g/cm³ is close to twice as heavy as iron. A one-inch cube of the 6% cobalt grade works out to about 0.54 pound, against roughly 0.28 pound for the same cube of pure iron.
Hardness spans a wide range too. ITIA places cemented carbide grades between about 800 HV10 on the tough side, where they meet high-strength steels, and 2800 HV10 on the hard side, next to hard ceramics. Its side-by-side pair shows a 6% cobalt grade at 1450 HV10 and a 20% cobalt grade at 800 HV10, with toughness of 12 and 25 MPa√m.
Sources: NIST: X-ray mass attenuation coefficients, Table 1 (element densities); NTP Report on Carcinogens, 13th edition: Cobalt-tungsten carbide powders and hard metals; OSTI: Brookhaven binderless tungsten carbide polishing study (2022); OSTI: Washington State University shock study of 3.7% and 6.0% cobalt grades (2023); OSTI: Oak Ridge National Laboratory binder-jet WC-Co study; ITIA: Cemented carbides, a success story (newsletter, June 2010); ITIA: International Tungsten Industry Association.
Tungsten carbide grades and the ISO groups
A carbide grade is a recipe. ITIA names the two main dials that tune it: the tungsten carbide grain size and the cobalt content. Per the NTP background document, hardness and abrasion resistance rise as the grains get finer and the cobalt drops.
Each job pulls the recipe its own way. ITIA's examples:
- Metal cutting: grains of 0.5 to 5 microns with 3 to 12% cobalt.
- Threading inserts: usually coated, fine grained, 8 to 12% cobalt, with titanium and tantalum carbides added.
- Mining and construction: coarse grains up to 20 microns and 6 to 10% cobalt.
- Water jet nozzles: near-nano grades with grains below 0.2 micron and a hardness of HV10 2800, used in nozzles that run water at up to 4000 bar.
The ISO letters P, M and K
The NTP profile describes three ISO groups for machining grades: P for machining steel; M for multiple purposes, steel, nickel-based superalloys and ductile cast iron among them; and K for gray cast iron, nonferrous metals and nonmetallic materials.
The NTP background document adds a caution: "The ISO application codes are for guidance only; the coding is at the manufacturer's discretion".
Sources: ITIA: Properties and intermediates; NTP background document: Cobalt-tungsten carbide hard metals (2009); ITIA: Cemented carbides, a success story (newsletter, June 2010); NTP Report on Carcinogens, 13th edition: Cobalt-tungsten carbide powders and hard metals.
Coated and uncoated carbide
Most inserts wear a hard skin a few microns thick. ITIA says more than 80% of turning inserts and about 70% of milling inserts are coated. Common coatings include TiN, TiCN, aluminum oxide, TiAlN, AlCrN and diamond.
The layers are thin. ITIA gives 5 to 20 microns for CVD (chemical vapor deposition) coatings and 2 to 8 microns for PVD (physical vapor deposition). ITIA notes that TiN is the gold-colored one.
For the zinc recycling process, ITIA says, coatings and solders have to be thoroughly removed from the parts first, or they stay in the recycled powder as contamination. That is a good reason to bag coated and uncoated pieces apart, and the sorting guide shows how.
Sources: ITIA: Cemented carbides, a success story (newsletter, June 2010); ITIA: Recycling of tungsten, part 2 (newsletter, August 2019).
Where cemented carbide goes
Cemented carbide is the largest use of tungsten in the country. The USGS Mineral Commodity Summaries 2026, covering 2025, says: "An estimated 60% of the tungsten consumed in the United States was used in cemented carbide parts for cutting and wear-resistant applications". Construction, metalworking, mining, and oil and gas drilling are the main users, per USGS.
The 2009 NTP background document puts the split at about 70% of hard-metal production for cutting tools and 30% for wear-resistant materials, mostly mining and grinding tools. On the ground that covers:
- Cutting tools: indexable inserts for turning, milling, threading and drilling, plus drills, reamers and routers.
- Wear parts: compacting dies and punches, wire drawing dies, seal rings, plungers and slitter knives.
- Mining and construction: road-milling chisels, buttons on roller cone rock bits, tunnel boring tools.
- Wood and stone: carbide-tipped saw blades, masonry drills, stump grinder and shredding bits.
Sources: USGS Mineral Commodity Summaries 2026: Tungsten; NTP background document: Cobalt-tungsten carbide hard metals (2009); ITIA: Cemented carbides, a success story (newsletter, June 2010); ITIA: Recycling of tungsten, part 1 (newsletter, May 2018); ITIA: Applications and markets.
Why scrap carbide is recycled
Worn carbide is still tungsten carbide and cobalt, and both metals are on the final 2025 List of Critical Minerals, published in the Federal Register on November 7, 2025. The Mineral Commodity Summaries 2026 reports no commercial tungsten mining in the United States after 2015, and the 2025 edition calls scrap an important source of raw material for the tungsten industry.
Cobalt gives recyclers a second reason. USGS Open-File Report 2005-1028 notes that higher cobalt prices encourage the recycling of cemented carbides, because they contain both metals.
The material recycles well: ITIA says cutting inserts for machining already pass 95% recycling rates in industrial settings. Sorted, clean hard scrap can go through the zinc process, while the chemical route takes almost any cemented carbide scrap, USGS says, and yields material equivalent to virgin. The carbide recycling page walks through both routes.
Sources: USGS: Interior Department releases final 2025 List of Critical Minerals (November 2025); USGS Mineral Commodity Summaries 2026: Tungsten; USGS Mineral Commodity Summaries 2025: Tungsten; USGS Open-File Report 2005-1028: Tungsten recycling in the United States in 2000; ITIA: Supply and circularity; USGS Open-File Report 01-349: Tantalum recycling in the United States in 1998; Federal Register: Final 2025 List of Critical Minerals (November 7, 2025).
Selling the carbide you are done with
We buy scrap carbide in any form, from inserts and end mills to brazed saw tips, road bits and grinding sludge. We also buy exotic metals and alloys.
Ship it from anywhere in the US and we pay the shipping, or we come to you and pick up in every city in California, Arizona and Nevada. We pay cash where state law allows. Each lot gets its own quote; the carbide scrap price page explains what moves the number.
Leave the pieces whole: we buy carbide as it comes, so there is no reason to grind or crush it into dust. NTP lists cobalt-tungsten carbide powders and hard metals as reasonably anticipated to be a human carcinogen.
To start, tell us on the quote form what form your carbide is in and about how much it weighs, and add a few photos. Or call (877) 838-9920.
Sources: NTP Report on Carcinogens, 13th edition: Cobalt-tungsten carbide powders and hard metals.
Questions sellers ask
Is tungsten carbide the same thing as tungsten?
No. Tungsten is a metal element, and tungsten carbide is a compound of tungsten and carbon. Pure tungsten is the heavier of the two. We buy both; see tungsten scrap.
Do you buy coated carbide inserts?
Yes. We buy carbide in any form, coated and uncoated alike. Bag them apart if you can; see carbide inserts.
How can I tell carbide from high-speed steel?
Weight is the first clue: a carbide tool feels heavy for its size, since carbide is close to twice as dense as iron. Shape will not settle it, because high-speed steel is also made into drills, taps, milling cutters and saw blades. The magnet guide covers the other checks.
Can I sell carbide grinding sludge and powder?
Yes, we buy them. Keep them in sealed containers; the grindings and sludge page has the handling details.
Keep reading
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Learn moreHow to sort carbide scrap
Keep it clean and separated to get the most for it
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Is carbide magnetic?
The magnet test, and other ways to tell carbide from steel
Learn moreRods and blanks
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Learn moreCarbide inserts
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Learn moreGet a quote for your carbide
Tell us what form it is in, about how much it weighs, and send a few photos. Ship it to us from anywhere in the US and we pay the shipping, or we pick up in California, Arizona and Nevada.