Comparative study of stainless steel AISI 431 coatings prepared by extreme-high-speed and conventional laser cladding

Abstract

High quality 431 steel coatings were prepared on a 27SiMn substrate by extreme-high-speed laser cladding (EHLA) and conventional laser cladding (CLA), respectively. The cladding speed of the EHLA process was 150 m/min, and the surface rate could reach up to 1.14 m2/h, which is four times higher than that of the CLA process. The microstructure of the coatings was investigated in detail. The microstructure of both coatings was dominated by dendrites. Benefitting from the ultrahigh cooling rate, the dendrites of EHLA coatings were more refined than that of CLA coatings. The element distribution between dendrites and interdendritic regions was more uniform. The corrosion resistance was evaluated by electrochemical tests. The results indicated that the EHLA coatings performed better corrosion resistance due to the fine uniform microstructure.