Surface and subsurface alterations induced by deep rolling of hardened AISI 1060 steel

Among the several processes available for the inducement of compressive residual stresses by means of cold work hardening, deep rolling is one of the most widely used especially in the case of solid rotationally symmetrical components, such as axles and shafts. This work investigates the effect of two deep rolling parameters, namely rolling pressure and number of passes, on the surface topography, surface near residual stress, amount of retained austenite and subsurface microhardness distribution of hardened AISI 1060 steel. The results show that after deep rolling the surface topography is characterized by a plasticized zone without evidence of spalling or cracks. A 10-fold decrease in surface roughness is provided by deep rolling and an appreciable reduction was observed for the material ratio curve parameters. Compressive residual stresses were found near the surface after deep rolling and increased particularly with an increase in rolling pressure. In contrast, the highest value for the full width at half maximum was recorded under the lightest deep rolling condition. The amount of retained austenite reached its highest value when rolling with pressure of 200 bar and one pass and was associated with the thickness of the white layer. Finally, the microhardness beneath the surface increased with rolling pressure and was negatively affected by number of passes.