Casting P-900 Armorplate by the Expendable Pattern Casting Process.

摘要

Constant research and development on armorplate for armored military vehicles is required to shield troops against new ballistic threats. The U.S. Army Tank and Automotive Command requested that the U.S. Bureau of Mines assist in research on P-900 armor because of previous Bureau research on innovative expendable pattern casting (EPC) methods of casting steel. The Bureau of Mines developed a system for casting unique, slotted steel armor by modifying the conventional expendable pattern casting (EPC) process that is normally used for making aluminum castings. Three innovations were added to the EPC process to make the successful adaptation: (1) Vacuum was applied to sand molds, (2) continuous narrow-necked feeding systems were used to permit the casting of thin walls, and (3) fixtures were designed to prevent pattern damage and to hold critical casting tolerances. Potential problems and defects are described.