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 CO, laser and Ar shielding gas that was bl own into a molten pool. The cracking susceptibility and microstructure of t he laser-clad layer were studied in terms of Co additions. Co can change th e microstructure of a Fe-Cr-Ni alloy clad layer from eutectic to hypoeutect ic and decrease the cracking susceptibility of clad layers. However, these results relate not only to the Co content in the laser-clad alloys, but als o the number of overlapping tracks. With the increment of Co content in dad layer, the cracking susceptibility of the laser cladding layer decreases a nd the number of overlapping tracks with hypoeutectic structure increases. At the same time, Co does not change the hardness of the clad layer. (C) 20 01 Elsevier Science B.V. All rights reserved.