Effect of laser surface treatment on the dry sliding behaviour of the EN-GJS400-12 ductile cast iron

Laser surface treatment (LST), using two levels of laser energy intensities, was carried out on ductile cast iron GJS400; the corresponding effect on microstructure and dry sliding wear behaviour was studied. The tests were carried out against a carburized steel also on the untreated GJS400 and lamellar GJL300 cast irons, for comparison. LST enhanced the wear resistance of GJS400, while leading to an increase of its coefficient of friction (COF). The best performance was observed in the cast iron treated at the lower energy intensity, leading to a lower surface hardness and related superior toughness. Among the untreated cast irons, the GJS400 presented the best tribological behaviour, due to the positive effect of graphite nodules in respect to flake graphite