Direct comparison of Cold Metal Transfer to laser hot-wire cladding for AISI 4340 structural steel repair

Repair, rather than replacement, of large, high-value structural components can reduce overall operating costs, with wire-based cladding techniques preferable due to their relatively high deposition rates. Two such techniques, laser hot-wire cladding and Cold Metal Transfer, are particularly attractive for their low heat input, which reduces distortion, filler metal dilution and thermal effects on the substrate. However, literature studies on the use of these techniques for structural steel repair are limited, with no studies offering a direct comparison of their performance. In the present work, laser hot-wire cladding is directly compared to Cold Metal Transfer for the repair of AISI 4340 structural steel. Simulated repairs using the same base/filler metal and joint geometry are characterised in terms of distortion, microstructure, tensile and impact properties. The results show that, despite having similar laser and arc energies, the two techniques resulted in significantly different properties, generally due to differences in process efficiencies.