Effect of spot overlapping rate on surface area carbon and oxide cleaning quality of GH3030 alloy

A 200 W nanosecond pulsed fiber laser is used to study the laser cleaning of surface area carbon and oxide of GH3030 nickel base superalloy. The effects of laser spot overlapping rate on the cleaned surface morphology, element composition, phase composition, surface roughness and microhardness are analyzed. The results show that as the overlapping ratio of laser spot increases from 58.33% to 70.83%, the content of carbon and oxygen decreases first and then increases, the content of nickel increases first and then decreases, and the surface roughness decreases first and then increases. When the spot overlapping rate is 66.67%, the contents of carbon and oxygen decrease to the lowest value, which are 5.01 wt% and 1.40 wt% respectively. At the same time, the content of nickel reaches the peak, which is 72.96 wt%. The surface roughness Ra decreases to 0.229 μm and Rz reduces to 1.47 μm. The change of laser spot overlapping rate will not have a significant impact on the surface microhardness of GH3030 superalloy.