High-strength steels, particularly in quenched and tempered condition, are widely used in marine engineering for critical components, like shafts and crankshafts, due to the excellent combination of strength and toughness. However, during operation, these components may frequently encounter continuous friction, operational stresses, and exposure to harsh marine environments, resulting in surface wear, discontinuities, and corrosion, ultimately leading to material degradation. In this study, a High-Power Diode Laser (HPDL) was used to apply two types of coatings - AISI 410L and a 50% mixture of AISI 410L/AISI 4140 - onto a shaft made of quenched and tempered EN 42CrMo4 steel. Each coating consisted of two deposited layers on the EN 42CrMo4 steel shaft. Following the laser cladding process, a set of coated components underwent a post-cladding heat treatment for stress-relieving purposes. A microstructural study was performed on sections of the coatings revealing in each case, the degree of dilution, the extent and characteristics of the heat-affected zone, the microstructural characteristics of each deposited layer and layer interface, and the microhardness profile. A comparative analysis of the results was conducted to strengthen the conclusions.