Effect of relative strain ratio on the reduce roughness surface layer tube holes after burnishing process

Burnishing technology is a technology of surface plastic forming of machine parts. The paper presents experimental research of burnishing process of the steel tube holes. Used tools to burnishing technology are hard and smooth surface. Burnishing elements are of ball, roll and disk. Burnishing be flat surfaces, and cylindrical shape. Burnished surfaces are cylindrical outer and inner. Because of the type of the force can be divided into static and dynamic burnishing. Due to the kinematics can be divided into sliding and roller burnishing. Occurrence of moving parts in direct contact with the material qualifies for the group process of burnishing rolling. The sliding burnishing design element property is part of the work surface burnished permanently attached to the handle. Burnishing is used as a finishing strengthens and smoothness can be realized on the universal machine tools and machining centres, effectively replaces the machining operations, such as grinding, reaming, honing and lapping. The precise tube holes are made mostly methods abrasive machining. Machining these methods can usually maintain a within the tolerances established by the constructor size and shape and surface roughness. However, there is not achieved a satisfactory state surface layer of tube holes. Improve the properties of the surface layer can be obtained after application, as finishing, broaching the slide burnishing. It consists in pushing through the machined hole tool in the shape of a sphere or a special plunger mandrel. After burnishing broaching is increased diameter, reduced roughness surface and improve the physical properties work piece surface layer of the tube holes. Burnishing broaching process can increase the dimensional accuracy of tube holes, reducing the surface roughness, the strengthening of the surface layer, compressive residual stresses constitution. Compressive internal stresses substantially influence the fatigue life of machine parts. A burnishing broaching is carry out by a ball. In the paper presents results measurements roughness and impact of the relative strain ratio on the surface layer after burnishing broaching process.