Multi-criteria optimization of steel burnishing parameters applied to marine pumps shaft pins

The paper presents the research results of the possibilities of applying burnishing as steel finishing treatment for marine pumps shafts. X5CrNil810 (AISI304 L) corrosion resistant steel in the form of a roller 40 mm m diameter was used for the research. The burnishing process was carried out by SRMD single roll burnish by Yamato. During the process of burnishing various parameters of the technological process were used, that is burnishing force, speed and feed. Within the research, the optimization of burnishing technological parameters was conducted on account of the minimalization of Ra coefficient as we 11 as the maximalization of Su. The Slt coefficients values determining the degree of relative hardness of surface layer varied depending on the burnishing parameters applied and fluctuated around l% to 18%. However, the values of KRa coefficients defining the surface roughness reduction index were in the range of l to 15 as a result of burnishing. The object of the paper was to determine the optima! burnishing parameters in order to achieve the highest level of surface layer relative hardness and to decrease the surface roughness of marine pumps shaft pins made of stainless steel. The multi-criteria optimization conducted with the use of min-max method demonstrated that with regard to maximum surface hardness level, burnishing should be carried out at the following parameters of the technological process: burnishing force 1.1 kN, burnishing speed 35 m/min and feed 0.13 mm/rev.