“…Dzierwa and Markopoulos [ 20 ], who also have studied the surface roughness and residual stresses of the 42CrMo4 steel, reached similar conclusions about the positive effects of the BB process. A large amount of published works [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ] show that the application of different finishing methods, related to plastic deformation in the surface layer of the different materials, can significantly increase the surface integrity and fatigue life of the parts, subjected to the cyclic load.…”