Study on single-pass forming process parameters of laser direct deposition of Fe55 alloy

Abstract

Using laser direct deposition, Fe55 alloy powder was deposited on the surface of the Q235 steel plate. The effects of scanning speed and laser power on the forming morphology, microstructure and hardness of single-pass deposition coating were analyzed. The results show that the height and width of the coating increase first and then decrease with the increase of laser power when the scanning speed is 5 mm/s. Compared with the 1700 W and 1900 W coatings, the microstructure in the middle of coating with 1800 W is the smallest, and its microhardness is the highest, with an average value of 892 HV. When laser power is 1800 W, the height and width of the coating decrease with the increase of scanning speed. Compared with the 4 mm/s and 6 mm/s coatings, the microstructure in the middle of coating with 5 mm/s is the smallest, and its microhardness is the highest, with an average value of 866.6 HV. The optimal process parameters such as laser power 1800 W, scanning speed 2 mm/s, defocus distance 304 mm, and powder feeding rate 0.14 g/s are ascertained for singlepass deposition of Fe55 alloy powder.