Affiliation:
1. School of Materials Science and Engineering Lanzhou University of Technology Lanzhou 730050 China
2. Hardware Knife Cut Industrial Technology Research Institute Yangjiang Yangjiang 529533 China
3. Gansu Precision Machining Technology and Equipment Engineering Research Center Lanzhou 730050 China
Abstract
Fe‐0.3C‐15Cr‐1Ni high hardness corrosion‐resistant alloy coating is prepared on the surface of 3Cr13 by laser cladding technology. The effects of scanning speeds on the microstructure, microhardness, and corrosion resistance of the coating are studied. The results show that the microstructure of the cladding layer is mainly composed of intracrystalline martensite and carbides distributed along the grain boundaries. When scanning speed increases from 3 to 5 mm s−1, the grain is obviously fined, and the number of carbides increases, further increasing scanning speed, the grain refinement degree decreases and the carbide quantity decreases gradually. When scanning speed is 5 mm s−1, the microhardness reaches the maximum, the corrosion resistance is significantly improved at 5 and 7 mm s−1, and the pitting potential and passivation zone width increase by 180–219% and 69–78%, respectively, compared with 3 mm s−1 sample, but further increases scanning speed to 9 mm s−1, the hardness and corrosion resistance significantly reduce. This is because scanning rate affects the component undercooling degree of the dynamic molten pool and the temperature gradient at the solidification interface front, which affects the growth of dendrites, the number of carbides, and further affects the alloying elements in the carbide and matrix.
Funder
Innovative Research Group Project of the National Natural Science Foundation of China
Natural Science Foundation of Gansu Province
Science and Technology Planning Project of Guangdong Province