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Selling worn carbide dies, nozzles and seal rings
Carbide wear parts scrap is the hardware that wore out holding a shape instead of cutting one: draw dies, nozzles, seal rings, feed rolls, punches and bushings. We buy all of it, cracked or whole, and pay the shipping from anywhere in the US.
The jobs that use up a carbide part
Not all carbide cuts. A National Toxicology Program background document (2009) puts about 30% of hard-metal production into wear-resistant parts and about 70% into cutting tools. It names mining and grinding tools as the biggest wear uses; mining bits have their own page. This one covers the carbide that lives inside machines.
The very first job for cemented carbide was a die. ITIA, the tungsten industry association, writes that the 1923 patent was filed in Berlin and that the first use was a drawing die for lamp wire. The work never stopped: in ITIA's words, “billions of kilometers of steel and copper wire are annually drawn through cemented carbide dies”.
ITIA's list of carbide structural parts reads like a tool crib count: plungers, boring bars, compacting dies and punches, high-pressure dies and punches, seal rings, pulverizing hammers, needles, feed rolls and chuck jaws. Large parts such as rolls are mostly pressed as one block and then machined to shape.
Sources: NTP Report on Carcinogens background document: cobalt-tungsten carbide (2009); ITIA: Cemented carbides, a success story (2010).
Carbide or hardened steel: let the weight decide
A ground bushing or a polished ring looks the same in carbide, hardened steel or ceramic. Hardness will not sort carbide from ceramic either: a 2022 paper says tungsten carbide's hardness is comparable to alumina and silicon carbide.
Weight sorts carbide from steel. A University of Pennsylvania lecture puts carbide at generally 1.5 to 2 times the density of steel, and an MIT table lists two common steels, 1020 and 4340, at 7.8 g/cm3. Measured carbide grades sit well above that: 15.17 g/cm3 at 3.7% cobalt, 14.91 at 6% cobalt, and about 13.1 for a part with roughly 19% cobalt.
ASTM B311, the standard density test for cemented carbides, is based on water displacement, and you can run a rough version with a kitchen scale. Weigh the part dry, then weigh it hanging on a thread under water. Water is roughly 1 gram per milliliter, so the grams it loses equal its volume in cubic centimeters.
- A ring at 300 g dry and 280 g in water has lost 20 g, so 300 / 20 = 15.0 g/cm3. That is carbide territory.
- A steel ring of the same 20 cm3 would weigh about 20 x 7.8 = 156 g.
- Under 7.8 is lighter than steel and below even the lightest grade, 8.5, in an NTP table of representative steel-cutting grades, so it is most likely not carbide.
- Between steel and about 13 proves nothing either way, since those steel-cutting grades run 8.5 to 13.4.
Two cautions from ASTM: density alone cannot prove a grade, and a part that gains weight in the water has open pores and reads too high. See also identifying carbide.
Sources: OSTI 1981641 (2022); ITIA: Cemented carbides (2010); University of Pennsylvania IPD 501 lecture; MIT 3.11 metals table (1999); OSTI 2376169 (2023); ORNL, OSTI 1607097 (2019); ASTM B311-22; USGS Water Science School: water density; NTP background document (2009).
Nickel binders, and parts that ran wet
Most wear parts are tungsten carbide held together with cobalt. ITIA says WC-Co is the general choice for wear parts, but where corrosion matters, makers also consider cobalt-nickel-chromium, nickel-chromium, iron-nickel-cobalt and pure nickel binders. A 2023 paper calls it well known that nickel in place of cobalt improves corrosion resistance.
The reason is what liquids do to cobalt. In aggressive media, a 2021 study found, corrosion dissolves the cobalt and leaves a skeleton of tungsten carbide grains on the surface.
For you this means two things. Seal rings and nozzles that ran in water or chemicals may be a nickel grade, so if your records say so, bag them apart and note it on the form. And a die with a dull, etched bore is still carbide; send it.
Sources: ITIA: Cemented carbides (2010); Materials 2023;16(12):4480; Materials 2021;14(20):6130.
Getting a box of dies ready to go
Leave each part the way it came out of the machine. A die still in its steel case can travel in the case; do not grind, saw or press carbide out of anything. The National Toxicology Program names sharpening and grinding of hard-metal products among the sources of cobalt and tungsten carbide dust, and it lists cobalt-tungsten carbide hard metals and powders as reasonably anticipated to be a human carcinogen.
Wipe off loose oil, let wet parts dry, and keep dies, nozzles and rings in separate bags if you have the time. Carbide is heavy for its size, so a small box gets heavy long before it looks full. USPS rules put dense items such as tools and machine parts weighing 20 to 45 pounds in a box of at least 200-pound test board, or an equal wood, metal or plastic container, and heavy items must be held still inside the package. Our shipping page has the rest.
Sources: NTP Report on Carcinogens profile: cobalt-tungsten carbide; USPS Domestic Mail Manual 601.
How we buy your dies and wear parts
Fill in the quote form and pick “Dies & wear parts”. Tell us what the parts are and about how much they weigh, with a few photos. If you would rather not use the form, send the photos to help@carbidebuyersusa.com or ring (877) 899-5778. Every lot is different, so we quote each one from its photos, form and weight.
Ship dies from any state and we pay the shipping. If you are in California, Arizona, Utah or Nevada, we can come to your shop instead; we pick up in every city of those four states. Payment is cash where state law allows it. How much paperwork a sale takes depends on the state, and our guide to the four states' scrap laws covers it.
We also buy exotic metals and alloys, bagged apart in the same shipment.
Common questions
Can carbide nozzles scrap go in the same box as the dies?
Yes. Bag nozzles, dies and rings apart if you can and list each kind on the quote form, so the photos and weights match what is in the box.
What if I cannot tell whether a ring is carbide or ceramic?
Put it in its own bag marked unsure and say so on the form. The water check above sorts carbide from steel, not from ceramic. Unknown parts mixed into known carbide make the whole bag harder to quote.
Do you buy carbide dies scrap with a nickel binder?
Yes. We buy carbide in any form, whatever holds the grains together. If you know a part is a nickel grade, keep it separate and note it.
More for sellers
How to identify carbide
Telling carbide from steel and HSS in a toolbox
Learn more
Rod, blanks and drops
Carbide rod, blanks, drops and broken pieces
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Mining bits and road teeth
Button bits, rock bits and road-milling teeth
Learn more
Ship your carbide
Packing heavy carbide so it arrives in one piece
Learn more
Sorting carbide scrap
What to keep together, what to separate, and why
Learn moreReady to sell your carbide?
Send a few photos and a rough weight. From any state, you ship it and we cover the shipping; in California, Arizona, Utah and Nevada, we drive out to you.