In this report, an electron beam surface treatment technology is introduced by which applies a cladding layer of defined thickness is deposited on an austenitic steel (e.g., X6CrNiMoTi17-12-2) and a duplex steel (e.g., X2CrNiMoN22-5-3). The applied cladding alters the microstructure and, thus, the properties of the material's surface layer in such a way that a considerable improvement in mechanical properties is achieved. The Co- and Fe-based additives used are deposited thermally to the base material in wire form by means of an electron beam (EB). The layer produced in this manner is free of cracks and pores, and is firmly bonded metallurgically to the substrate material. The cladding layers are evaluated with respect to their modification of the microstructure of the substrate material, and with respect to their effect on hardness. As a result of the high heating and cooling rates during EB application, an extremely fine, dendritic microstructure with homogenously distributed additive elements and low substrate material contents of between 19 and 37% is produced. An increase in hardness of between 2 and 3 times the hardness of the substrate material is thereby achieved.