THE AIR FORCE has set up a program to evaluate the machining characteristics of the more commonly used high-strength thermal-resistant materials. This paper describes the test results to date.
Four materials are being tested: SAE 4340 quenched and tempered to 50–55 Rockwell C, SAE designation H11 quenched and tempered to 50–55 Rockwell C, AM-350 solution treated and aged, and A-286 solution treated and aged. Machining tests include: turning milling, drilling, and tapping.*