The melting parameters for an AlSi12 alloy, which lead to surface-melted layers with constant melting depth and smooth surface have been discovered using the electron beam melting technique. The main mechanical properties of the melted layer were determined with different testing methods, which were adapted for this specific use. Examination under quasistatic stresses showed an increase of the hardness of 60% compared with the base material. The tensile strength increased in the melted layer by about 50%, whereas the elongation was not reduced drastically. Examination under fatigue stress resulted in a reduced fatigue strength of the surface-melted samples. The reason for this was crack initiation at pores at the boundary of melted layer and base material. For a poreless melted AlSi12 alloy, however, the same fatigue strength as for the base material was found.