Laser surface alloying of plain carbon steels

Deposition and alloying of metallic powders containing WC on a ferritic-pearlitic plain carbon steel have been investigated. Metallic powder was injected into the melted surface layer of the samples under Argon atmosphere during the laser irradiation. The sample surface was previously graphitizing treated to prevent energy loss by reflection. For comparison, irradiated samples, without powder alloying, were also analysed. The coating layer is mainly composed of alloyed α-Fe; γ-austenite and non-magnetic M₃C carbide are also present. Partial dissolution of WC and the preliminary graphitizing treatment are the causes of the rather high carbon concentration in γ-austenite. As it is to be expected this concentration decreases with increasing distance from the external surface of the coating layer.