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

摘要

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.