The analysis of finish tooling influence on contact fatigue of steel applied to sea water pump shafts

The article presents the research results referring to the analysis of the influence of finish treatment (lathing, grinding, burnishing) on the contact fatigue of steel applied to marine pump shafts. The research was performed on a roller 25mm in diameter made of X5CrNi18-10 (AISI304 L) stainless steel. The lathing process was carried out by means of a Sandvik Coromant cutting too, the grinding was done by grinding attachment to a lathe, whereas the process of burnishing was performed by SRMD burnisher by Yamato. Within the research, the optimalization of burnishing technological parameters was conducted on account of the minimalization of Ra surface roughness coefficient as well as the maximalization of SU degree of surface layer relative hardness. The multi criteria optimalization conducted by min-max method with regard to minimum surface roughness as well as maximum degree of surface layer hardness demonstrated that burnishing process should be carried out at the following technological parameters: burnishing force 1.1 kN, burnishing speed 35 m/min, feed 0.13 mm/rev. In addition, the influence of the burnisher passes number on the surface layer quality was determined. It is essential for this research to determine the burnishing influence on the service conditions which comprises the electrochemical corrosion research, friction wear and contact fatigue research. The paper will present the research results of contact fatigue examination of samples after finish machining.