The microstructure of surface boron alloyed layer has been investigated by XRD,TEM and SEM techniques. The results showed that in the hypereutectic region the micrograph of eutectic structure composed of Fe\-2B and austenite may be in the shape of chrysanthemum or a fish\|bone type. The austenite transforms finally into Fe\-3(Si,B) plus ferrite phase with a pearlitic or bainitic structure.
