The processing of plastics which contain chemically aggressive or abrasive fi llers demands hardenable, corrosion-resistant steels. This reduces the mould maintenance necessary in comparison to steels which are less corrosion resistant.
Pre-heat-treated steels: Steels which are supplied and used in the heattreated condition. The hardness of approx. 30 HRc (similar to the non-corrosion-resistant heat-treatable steels) is an optimum compromise between machinability and wear resistance / compressive strength. In special cases, a higher working hardness may be used.