Microstructural influence of consecutive deep rolling of AISI 4140

Deep rolling is used to increase the in-service life of parts due to reduced roughness, induced compressive residual stresses, and hardness alterations within the surface and subsurface layer. Depending on the process parameters, the same element of the material is affected multiple times by the deep rolling tool. This paper analyzed the influence of consecutive deep rolling processes on the microstructural properties of AISI 4140. Microstructural cross-sections, hardness measurements, FWHM- and EBSD mapping were used to characterize the surface and surface layer after deep rolling and to identify the influence of the processes on the material’s microstructure.