The selection of tool steel is very important for any tool upon which the development and economical operation of the process depends. Care should be taken especially while injection moulding plastics, which may affect the factors like mould life, quality, cost of mould and machine etc.

The steel used in the manufacture of mould varies depending on the applications. Proper material selection and proper combination of alloys in varying percentages are required for finished moulds.

Following properties are desired from the steels used in mold making

· Characteristics permitting economical machining

· Capacity for heat treatment without problems

· Ease of polishing

· High Wear resistance

· High Thermal conductivity

· Good Corrosion resistance

· Good Toughness