Effect of solution aging treatment on microstructure and properties of Fe‐0.5C‐11Cr corrosion resistant alloy by laser cladding

Fe‐0.5C‐11Cr corrosion resistant alloy coating was prepared on the surface of 3Cr13 stainless steel by powder feeding laser cladding, and the microstructure of the coating layer was controlled by solution aging treatment. The microstructure of the coatings was measured by scanning electron microscopy, and phase composition was determined by X-ray diffraction. The hardness and corrosion resistance of coatings before and after heat treatment were evaluated on microhardness tester and electrochemical workstation, respectively. The results show that the morphology, size and quantity of dendrite carbides in the cladding layer of Fe‐0.5C‐11Cr alloy can be improved by solution and aging treatment. The eutectic carbides in the cladding layer can be changed from block, bone, continuous network of grain boundaries to round granular and discontinuous short rod by solution and aging treatment, which greatly improves the uniformity of the microstructure. There is a dynamic equilibrium and critical time for the melting and growth of carbides at 1050 °C. When the holding time is less than 20 min, the size of carbide decreases with time. After 20 min, fine carbides agglomerate and grow with time. The hardness of the cladding layer after heat treatment is about 9% higher than that of the cladding layer without heat treatment and the uniformity of the hardness is improved. The corrosion resistance of the sample kept for 20 min at 1050 ℃ is the superior because the pitting potential and passivation zone width of the coating kept at 1050 ℃ for 20 min increased by 21.5% and 19.2% compared with the cladding laser without heating, respectively.