The Past and Present of Cemented Carbide: How We Escaped the 200°C Trap

Before high-speed steel (HSS) existed, ordinary steel softened above 200°C. Cutting speeds? Less than 10 meters per minute. For machinists, that meant slow, hot, expensive work.

Everything changed in 1898 with the discovery of secondary hardening.

That breakthrough gave us T1 — the first true high-speed steel. Suddenly, steel stayed hard up to 600°C, and cutting speeds tripled to 30 meters per minute.

A leap? Absolutely. But industry always wants more.

Metallurgists understood HSS’s secret: a steel matrix packed with ultra-fine carbide particles. Think of it as concrete — the steel is the cement, the carbides are the gravel.

Two schools of thought emerged.

Path One: Push the steel further. Add more tungsten, vanadium, cobalt. Build stronger grades: T15, M2, M42. But there was a hard ceiling. Once the steel matrix enters the austenite zone, it softens instantly. No matter how hard the carbide grains are, without support, the cutting edge collapses in milliseconds.

Path Two: Abandon steel entirely. If the steel matrix is the weak link, why not remove it? Use pure carbide as the cutting tool.

As early as the 1890s, Henri Moissan had synthesized tungsten carbide in the lab — hardness approaching diamond. But pure WC was catastrophically brittle. Like a biscuit. One tap, and it shattered.

Making it tough enough for real machining?

That took 30 more years.

The rest — as they say — is history. And the history of cemented carbide is still being written.