MITSUBISHI MATERIALS CORPORATION
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CUTTING TOOL MATERIALS

Cemented carbide (WC-Co) was developed in 1923 and was later improved by adding TiC and TaC. In 1969, CVD coating technology was developed, and coated carbide has since been used widely. TiC-TiN based cermet was developed in 1974. Today, "Coated Carbide grades for roughing and cermet for finishing" is a well established trend.
Cutting Tool Materials
GRADE CHARACTERISTICS
Hard Materials Hardness
(Hv)
Energy Formation
(kcal/g·atom)

Solubility in Iron
(%.1250°C)

Thermal
Conductivity
(W/m·k)

Thermal * Expansion
(x10-6/k)

Tool Materials
Diamond > 9,000 - Highly Soluble 2,100 3.1 Sintered Diamond
CBN > 4,500 - - 1,300 4.7 Sintered CBN
Si3N4 1,600 - - 100 3.4 Ceramics
Al2O3 2,100 -100 0 29 7.8 Ceramics Cemented Carbide
TiC 3,200 -35 < 0.5 21 7.4 Cermet
Coated Carbide
TiN 2,500 -50 - 29 9.4 Cermet
Coated Carbide
TaC 1,800 -40 0.5 21 6.3 Cemented Carbide
WC 2,100 -10 7 121 5.2 Cemented Carbide
*1W/m•K=2.39×10-3cal/cm•sec•℃