MACHINING OF NEW MATERIALS

The machining characteristics of four groups of alloys were investigated which were (1) high strength steels, (2) stainless steels, (3) titanium alloys, and (4) nickel-base alloys. Specific materials were selected from a field survey and literature search made to determine which alloys of interest to the aerospace industry required machining data. Tools of conventional design were used in this program. Wherever possible, special tool materials, cutting fluids, and tool geometries were used in an attempt to get greater tool life. It was found that most of the alloys could be machined with fairly good tool life, providing specific conditions were used. However, some of the alloys, particularly the nickel-base group required very low cutting speeds. From the tool life curves obtained, machining recommendations were made for each of the operations covered. A study was also included in this program on the surface integrity of several of the test materials. Surface integrity is defined as the extent to which the physical and mechanical characteristics of the surface layers of a component match those of the bulk material. An abbreviated program was also carried out involving the application of photoelastic techniques to surface integrity studies. (Author)