Vacuum laser cladding and effect of Hf on the cracking susceptibility and the microstructure of Fe–Cr–Ni laser-clad layer

An investigation is reported of the laser surface cladding of self-fluxing Fe–Cr–Ni alloys on a medium carbon steel substrate using the preplaced powders method with gas shielding or vacuum protection. The cracking susceptibility and microstructure of the laser-clad layer have been studied in terms of Hf additions. Hf can change the microstructure of the Fe–Cr–Ni alloy clad layer from eutectic to hypoeutectic. The lowest cracking susceptibility occurs when the Hf content in the laser-clad layer is approximately 0.9% wt. But to achieve this effect there must be 3.0% wt. Hf in the alloy powders when shielding with gas. The effect of the protecting condition on cracking susceptibility of the laser-cladding layer is also reported