Burnishing apparatus for providing a layer of compressive residual stress in the surface of a workpiece

摘要

The burnishing method and apparatus (100) for implementing the method of the present invention utilizes a single-point burnishing process to provide deep compression with a minimal amount of cold working and surface hardening. In particular, the area to be burnished along the surface (178) of a workpiece (144) is defined and a freely rotating burnishing ball (114) is forced against the surface of the workpiece (144) to produce a localized area of deformation having a deep layer of compression within the surface. The burnishing ball (114) is then rolled over the surface in a substantially nonoverlapping pattern. A preferred embodiment of the burnishing apparatus (100) for implementing the burnishing method comprises a socket (108) having a tip member (104) incorporating a ball seat (110), a burnishing ball (114) disposed within the ball seat (110), a rod member (106) integrally formed with the tip member (104); and a socket support (102) for supporting the socket (108) on a conventional tool holder. The socket (108) is provided with means for directing lubrication fluid from an external reservoir to the ball seat (110) to permit the burnishing ball (114) to freely rotate and for directing a predetermined amount of lubrication fluid to the surface (178) of the workpiece (144).