treating the surface of the workpieces in the area of the cut surface with a chemical composition throughwhich the oxidized or nitrided fraction of the surface is removed, and partially coating the surfacetreating the surface of the workpieces in the area of the cut surface with a chemical composition throughwhich the oxidized or nitrided fraction of the surface is removed, and partially coating the surfaceof the workpieces in the region of the cut surface.