m303BÖHLER M303 is a pre-hardened martensitic chromium steel with very hh toughness, wear resistance and machinability. It is suitable for tools processing corrosive moulding compounds, e.g. PVC, and for food and beverage contact.BÖHLER M303 is a pre-hardened martensitic chromium steel with very hh toughness, wear resistance and machinability. It is suitable for tools processing corrosive moulding compounds, e.g. PVC, and for food and beverage contact.