Surface Integrity in Dry Milling of 304L Steel: A Parametric Study

Austenitic stainless steels represent a significant portion of the metallic components employed in the nuclear industry. In this paper, a detailed study of machining of Type 304L steel in dry milling was performed with the aim of characterising the response of the components’ surface quality and microstructure to variations of the cutting speed, depth-of-cut, and feed-per-tooth. Surface roughness parameters were optically evaluated and X-ray diffraction (XRD) residual stress measurements were employed to measure the extent of machining abuse on the surface. In addition, deformation in the sub-surface layer was examined via scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The experimental measurements of surface roughness and surface residual stresses were used to test a statistical model developed to optimise the selection of the process parameters. Preliminary results showed the effects of machining parameters to residual stresses and near-surface deformation levels in finished components. The ultimate aim of this work is to illustrate the availability of cost-effective materials and manufacturing techniques to the nuclear industry, alongside meeting the high standards of the required properties.