Abstract

In industry, structural parts generally work under cyclic loading. After a while under these loads, microcracks usually start on the surface. The microcracks grow into macrocracks and cause fatigue and fracture of the material even at stresses far below the yield strength. It is possible to increase the fatigue strength of materials with several surface treatments. One of the most common of these processes is the roller burnishing process. In this study, the roller burnishing parameters that affect the surface integrity and fatigue performance of AISI 4340 was optimized. Optimum levels of burnishing depth, feed rate, and burnishing speed were determined using Bees and Genetic algorithms utilizing the experimental results of a previously conducted study. Optimization was carried out by limiting the surface roughness -with a maximum surface roughness value of 1 micron. According to the bees algorithm, the optimum parameter levels were determined as 0.1 mm/rev for the feed rate, 0.109 mm for the burnishing depth, and 947 rpm for the burnishing speed. These levels were determined as 0.166 mm/rev for the feed rate, 0.115 mm for the burnishing depth, and 656 rpm for the burnishing speed for the genetic algorithm.