Evolution of the surface roughness of a low carbon steel subjected to fatigue

This work aims to analyze the evolution of the surface roughness of a low carbon steel (SAE 1020) subjected to different loads and fatigue life. The fatigue tests were performed by rotary bending. Images of the specimen surfaces were obtained by scanning electron microscopy (SEM) and analyzed by specific image processing software (SPIP™ - 3D Image Processing). The average roughness, extrusions (peaks), and intrusions (valleys) produced by persistent slip bands (PSBs) on the surfaces of the specimens were observed and quantified for different loadings and fatigue life. From the values of the peaks and valleys, as a function of the load and fatigue cycles, it was possible to determine the relationship between the evolution behavior of these parameters.