Capability of High Speed Laser Cladding Processes with Iron Based Alloys

High Speed Laser Cladding processes combine the benefits of conventional laser cladding with the high surface coverage rates of thermal spraying. Gas-tight thin layers (< 200 µm) with metallurgical bonding to substrates and high deposition efficiencies (> 85%) as well as high coverage rate (> 1.0 m²/h) characterize this process. However, the high speed variant of laser cladding is still in its infancy. There are limitations of the applicable material spectrum due to increased susceptibility to cracking as a consequence of extremely high cooling rates and narrow process parameter windows result in challenges for process development. This study aims for clarification of the applicability of High Speed Laser Cladding processes for production of iron-based alloy coatings, in particular 22% Cr 5% Ni duplex steel, FeCrV17 and FeCrNiB.

Process parameters are optimized for production of ~150 µm thin claddings on mild steel using different laser power levels, surface rates and pre-heating temperatures. Then, optimized parameters are welded on cylindrical substrates with different diameters to investigate dependency on component geometry.

Duplex steel shows robust processability in High Speed Laser Cladding processes. In contrast, crack free FeCrV17 hard facing alloy claddings can only be produced on small shaft diameters using preheating.