General
Uddeholm Mirrax 40 is a remelted stainless tool steel supplied prehardened to 40 HRC.
Uddeholm Mirrax 40 is produced using the electroslag remelting (ESR) process—an additional step in the steelmaking process that ensures very clean steel with low sulphur content (0.003% max.) and non-metallic inclusions. Consequently, Uddeholm Mirrax 40 is capable of being polished to a very high surface finish.
Uddeholm Mirrax 40 is characterized by:

• excellent machinability

• excellent polishability

• excellent ductility and toughness

• uniform hardness even in large dimensions

• good indentation resistance

• good corrosion resistance

These properties combine to give a steel with outstanding production performance.

The practical benefits of good corrosion resistance can be summarized as follows.

• Lower mould maintenance cost: The surface of cavity impressions retain their original finish over an extended service life. Moulds stored or operated in humid conditions require no special protection.

• Lower production costs: Since cooling channels are less likely to be affected by corrosion (unlike conventional mould steel), heat transfer characteristics and therefore cooling efficiency are constant throughout the mould life, ensuring consistent cycle times.

The benefit of the prehardened condition can be summarized as follows.

• No hardening risks

• No hardening costs

• Time saving, e.g. no waiting for heat treatment

• Lower tool cost (e.g. no distortion to rectify)

• Modifications easily carried out

Applications

• Injection moulds for corrosive and non-corrosive plastics

• Plastic moulding of high surface finish products (e.g., Bezels and casings for TV and computers)

• Blow moulding of corrosive plastics or high surface finish transparent products (e.g. PET bottles)

• Extrusion dies

• Constructional parts