LASER SURFACE-TREATMENT AND CORROSION BEHAVIOR OF MARTENSITIC STAINLESS AISI-420 STEEL

The effect of laser surface treatment of AISI 420 steel was studied. The operation conditions of the laser treatment were optimized with regard to beam power and displacement rate in order to produce different surface microstructures. The corrosion behaviour was studied as a function of the microstructures developed in the material. Maximum hardness was observed in the non-melted and carbide-free zone which was transformed into martensite. The best corrosion behaviour was observed in completely melted areas; this behaviour is similar to that observed in the starting material which is quenched and homogeneously tempered. Heterogeneous zones exist after laser heat treatment which have to be considered for final applications.