Deep cold rolling of single crystal nickel-based superalloy CMSX-4

Abstract

Nickel-based superalloys used in the aerospace industry are regularly subjected to high temperature and stress cycles. In order to extend component life, many components are subjected to a cold work process during manufacturing. One such technique is deep cold rolling, a highly controllable process which utilises a roller ball to impart cold work and deep compressive residual stress into a surface. In this study, local misorientation analysis of electron backscattered diffraction data has been used to quantify the surface cold worked layers in single crystal samples of the superalloy CMSX-4®, deep cold rolled with different pressures, ball diameters and roll orientations. As expected, it was found that greater pressure and ball diameter both increased the cold work depth, with pressure also affecting the amount of cold work per depth. Different roll orientations produced very similar distributions of cold work. In comparison with mechanical shot peening, another surface hardening technique, deep cold rolling is shown to produce a much deeper layer of relatively low cold work.