Electrical Discharge Machining (EDM) Gun Barrel Bore and Rifling Feasibility Study
Final rept. Jan 1973-Dec 1974
COLT INDUSTRIES INC DAVIDSON NC ELOX DIV
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A 12-month program was conducted to advance the technology of the Electrical Discharge Machining EDM process to be applicable to the stringent requirements of gun barrel boring and rifling. The type of barrels employed in the test were .220 swift gun barrel liners and gun barrel blanks. The various materials were selected on the basis of their resistance to withstand the high stress, high temperature, high pressure, high rate of loading, and high erosion rates encountered in high performance gun designs such as the GAU-7A and the GAU-8A. The materials investigated were ironnickel base superalloys, cobalt base superalloys, tantalum, columbium, and tungsten refractory alloys. These materials do not lend themselves to traditional types of machining, and an investigation was undertaken to see if advances in the state of the machining art, such as EDM, were capable of the task. The final effort on the program consisted of boring and rifling 18 gun barrel blanks for delivery to Philco-Ford Corporation, Aeronutronic Division, Newport Beach, California, for final fabrication and testing in .220 swift M-60 test barrels. These barrel blanks, however, were out of specification and could not be fabricated into test barrels.
- Fabrication Metallurgy