A comparative analysis of high speed and conventional laser-based directed energy deposition techniques focused on coating applications

This study presents a comparative analysis of two laser powder-based directed energy deposition (DED) techniques—conventional Laser Metal Deposition (LMD) and High Speed Laser Cladding (HSLC)—for coating high value-added components using the same hybrid machine. Experimental tests were performed to characterize the HSLC and compared with the results obtained in previous works associated with conventional LMD. The same base material (42CrMoS4 steel alloy) and two filler materials (a Ni-based alloy and an Fe-based alloy) were used in both cases, with tests performed on both preheated and non-preheated substrates. Powder efficiency, material deposition rate (MDR), coated surface per minute or coating rate (CR), argon consumption and microhardness were analyzed. The results indicate that for the Ni-based alloy, preheating the substrate is necessary in both techniques to avoid crack formation. In the case of the Fe-based alloy, cracks were only observed in the HSLC variant when the substrate was preheated. Significant differences in productivity were observed between the two technology variants for both materials, particularly in terms of CR and MDR, with HSLC showing a significant increase in both metrics. HSLC achieved coating rates between 4500 and 6860 mm²/min, representing a minimum productivity improvement of 130% compared to LMD. MDR values reached up to 1.72 kg/h for Ni-based and 1.39 kg/h for Fe-based alloys, significantly higher than the < 0.8 kg/h observed in LMD. Argon consumption per deposited kilogram was reduced by up to 80%. Maximum hardness values of 62–64 HRC (Fe-based) and 54–57 HRC (Ni-based) were achieved.

Funding: Financial support from the Basque Government under the ELKARTEK Program (ECOFAST project, grant number KK2024/00018) and from the Spanish Government under the CHINEKA Program (REP-RAIL project) is gratefully acknowledged by the authors.