Characterization of the Surface Integrity Induced by Hard Turning of Bainitic and Martensitic AISI 52100 Steel

Depending on the process parameters and the tool condition, hard turned surfaces can consist of a “white” and a “dark” etching layer having other mechanical properties compared to the bulk material. X-ray diffraction measurements revealed that tensile residual stresses accompanied with higher volume fraction of retained austenite are present in the thermally induced white layer. While compressive residual stresses and decreased retained austenite content was found in the plastically created white layer. The surface temperature was estimated to be ∼1200°C during white layer formation by hard turning.