What a grade actually is

Tungsten carbide grains bonded in a cobalt matrix. Finer grains and less binder mean harder and more wear-resistant; coarser grains and more binder mean tougher.

Grain size and binder content

Submicron and fine grains raise hardness and wear resistance at the cost of toughness. Coarser grains tolerate impact better and wear faster. Binder content moves the same trade-off in the same direction: more cobalt means more toughness and less hardness.

Hardness, density and porosity

Hardness and density are the two measurements a buyer can verify cheaply, and both are sensitive to porosity and to the accuracy of the powder blend. A grade specification that names them makes goods-in inspection possible without a laboratory.

Writing a grade specification

Name grain size, binder content, hardness range and the test method. Avoid trade names, which lock the specification to one supplier.

Properties instead of names

A specification written around measurable properties can be bid by several suppliers and verified on delivery. A specification written around a trade name can do neither, and it makes a second source impossible without a re-qualification.

Matching grade to the application

Abrasive surfaces want hardness; obstacle-heavy routes want toughness. Ice and road-planing tooling often wants a different grade again. The correct grade is a function of the failure mode, not of a general preference for harder or tougher.

Carbide grade questions

What makes one carbide grade harder than another?

Finer grain size and lower cobalt binder content. Both increase hardness and wear resistance, and both reduce toughness.

No. Harder grades resist abrasion and crack more readily under impact. The right grade follows from the failure mode the part actually experiences.

Hardness and density measurements are cheap and sensitive to grade and porosity. Naming them in the specification makes verification possible at goods-in.

They make the requirement single-source, which blocks competitive bidding and makes a second supplier impossible without re-qualifying the part.

Yes. The cobalt matrix is the part that corrodes, so higher binder content generally means more corrosion exposure in salt and moisture.

Ask about a grade for your application

Tell us the failure mode and the operating conditions and we will recommend a grade specification you can put out to bid.

✓ Application and duty
✓ Current failure mode
✓ Operating temperature and surface
✓ Volume and delivery destination

Email: [email protected]

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