Effects of scanning speed and scanning times on surface quality of line spot laser polishing of nickel-based superalloys

Nickel-based superalloy (DZ411) is widely used in aerospace and other fields due to its excellent physical properties, and the improvement of surface roughness is necessary in practical applications. In this paper, a machining platform that uses a beam shaper to modulate a circular spot into a line spot is used to perform laser polishing on the initial material surface by changing the scanning speed and scanning times, respectively. The results show that the line spot laser polishing can make the surface shallow melting to achieve the purpose of smoothing the surface. By changing the number of scanning times, the roughness of the polished surface Ra can be reduced from 0.702 μm to 0.354 μm. The percentage of improvement in surface roughness is 49.5%. The formation of oxides on the surface results in a slight increase in microhardness. In the test of changing the scanning speed, the roughness of polished surface roughness Ra can be reduced to 0.390 μm, Ra first decreases and then increases as the scanning speed increases. The polishing surface processing speed can reach 26.209 cm2/min, which has the potential to achieve efficient laser polishing. This research work can provide guidance for the optimization of line spot laser polishing parameters based on beam modulation and provide process data support for the efficient processing of nickel-based superalloy with line spot.