How tungsten carbide is made

Tungsten carbide is twice as dense as steel and about as hard as corundum, the mineral in sapphire.

stations: 5
things upstream: 21
raw sources: 11
steps from the ground: 5

The short version

Tungsten carbide is made by reacting tungsten powder with carbon at furnace temperatures between 1,400 and 2,000 °C. The gray powder is mixed with a metal binder, usually cobalt, pressed into shape and sintered until the binder melts and locks the grains together. Only diamond-class abrasives can finish it.

Cook tungsten with carbon

Tungsten metal powder and carbon are heated together in a furnace. They combine atom for atom to give a fine gray powder.

1,400 to 2,000 °C

Goes in
Tungsten Carbon black
Mill in a cobalt binder

The carbide powder is blended with a binder metal. Cobalt has been the standard binder since cemented carbide first reached the market.

Goes in
Cobalt
Press the powder to shape

Dies pack the powder into the rough shape of a tool tip or insert. The pressed piece is fragile and oversized because it will shrink.
Sinter until the binder melts

The part is heated until the binder turns liquid while the carbide grains stay solid. Grains pull together into a dense, tough composite.
Grind to final size

Only abrasives as hard as cubic boron nitride or diamond can polish and finish tungsten carbide.

End of the lineTungsten carbide Next it goes into ballpoint pen, saw blade.

Worth repeating

Tungsten carbide is about three times as stiff as steel and twice as dense.
Henri Moissan first made tungsten carbide powder in 1893.
WIDIA, an early trade name for cemented carbide, comes from the German for like diamond.