Tool steels are usually classified in four groups:

• Ledeburitic Cr-steels with less than 1% W - normally used for producing thread rolls and dies.
• Cold work steels with 0.5 - 3% W, of which cutting tools for instance are made.
• Hot work steels with 1.5 - 9% W, for dies and extrusion tools working up to 500°C and more.
• Steels for plastic moulding (which do not include W-bearing steel grades).