This paper deals with experimental investigation and numerical modelling of the tool wear in rough turning of large dimensions components of nuclear power plants made of 18MND5 steel. The tool wear has been characterised experimentally at microscopic scale using \SEM\ observations of different zones of the engaged cutting part at the tool rake face. A \FE\ model has been developed to predict the tool wear as observed on \SEM\ images. The major finding of the paper concerns the prediction of contact discontinuities at the microscopic scale on the tool rake face and where the wear process is highly localized. These discontinuities are attributed to the complex geometry of the rake face of the grooved cutting insert, designed especially to reduce the tool–chip contact area and to promote the chip breakage. The cutting force, specific cutting force and chip morphology parameters are also predicted and compared to experimental trends. This research work is a contribution for the tool wear prediction in rough turning to improve the tool life of complex cutting inserts at high material removal rate.