processes for general shapes

Die Casting - involves the injection of liquid metal into a multipart die under high pressure. Pneumatically actuated dies make the process almost completely automated. Die-casting is best known for its ability to produce high quality products at very low unit costs. Very high production rates offset the cost of the complex heat-resisting tooling required; and with low labor costs, overall casting costs are quite attractive.

The process can be used with several copper alloys, including yellow brass, C85800, manganese bronzes, C86200 and C86500, silicon brass, C87800, the special die casting alloys C99700 and C99750, plus a few proprietary compositions. These alloys can be die cast because they exhibit narrow freezing ranges and high beta phase contents. Rapid freezing is needed to complement the process's fast cycle times. Rapid freezing also avoids the hot shortness associated with prolonged mushy solidification. Beta phase contributes the hot ductility needed to avoid hot cracking as the casting shrinks in the unyielding metal mold.

Highly intricate copper alloy products can be made by die casting (investment casting is even better in this regard). Dimensional accuracy and part-to-part consistency are unsurpassed in both small (<1 in, 25 mm) and large castings. The attainable surface finish, often as good as 30 gin (0.76 [tm) rms, is better than with any other casting process. Die casting is ideally suited to the mass production of small parts.

Extremely rapid cooling rates (dies are normally water cooled) results in very fine grain sizes and good mechanical properties. Leaded alloys C85800 and C99750 can yield castings that are pressure tight, although lead is incorporated in these alloys more for its favorable effect on machinability than for its ability to seal porosity.

• Advantages of Die Casting
• Die Casting vs. Other Processes
• Die Casting Alloy Data
• Glossary of Die Casting Terms