| Superplast® 300 (SP300) is a prehardened steel with a BHN 300 (32 HRC) to be used for plastic injection molds, extrusion dies, and compression molds offering improved performance for the mold maker as well as the mold user. For a similar level of mechanical properties (wear resistance), this grade provides an easier and more reliable machinability than conventional steels (P20/W1.2311). This improvement is the result of a new chemical balance (lower carbon content and micro alloy additions) and a better microstructure. The homogeneity of the plate or block is improved compared to conventional steels, such as P20/W1.2311 which may be subject to hard spots. SP300 is designed to provide an improved weldability and machinability compared to P20/W1.2311. It is more compatible with finishing operations such as polishing and chemical etching. SP300 may open some new opportunities through the possibility of weld repairs allowing for design changes during manufacturing or production. SP300 is designed for use at 300 HB. If hardness is lost during the mold making process (by heating the steel to a temperature above 525°C (977°F), the original mechanical properties can be recovered by following a full cycle heat treatment. SP300 is well adapted to machining, (drilling or milling), with high speed steel as well as carbide tools. Its machinability is better than that of conventional P20. It ranks between the machinability of DIN grades W1.2311 (low sulfur) and W1.2312 (resulfurized). It can be machined using the same parameters as P20 with a much longer tool life, or increased feeds and speeds will enable a significant increase in productivity. Composition notes: Typical values for a 100 mm (4") thick plate. Boron is also present. Information provided by BICO Akron, Inc., a subsidiary of Groupe Arcelor. |
