Effects of Co on the cracking susceptibility and the microstructure of Fe–Cr–Ni laser-clad layer

The laser cladding of self-fluxing Fe–Cr–Ni alloys on a medium carbon steel substrate was performed using a CO2 laser and Ar shielding gas that was blown into a molten pool. The cracking susceptibility and microstructure of the laser-clad layer were studied in terms of Co additions. Co can change the microstructure of a Fe–Cr–Ni alloy clad layer from eutectic to hypoeutectic and decrease the cracking susceptibility of clad layers. However, these results relate not only to the Co content in the laser-clad alloys, but also the number of overlapping tracks. With the increment of Co content in clad layer, the cracking susceptibility of the laser cladding layer decreases and the number of overlapping tracks with hypoeutectic structure increases. At the same time, Co does not change the hardness of the clad layer.