Effect of Laser Cladding Parameters on the Microstructure and Properties of High Chromium Hardfacing Alloys

Mechanical components operating under high-stress and high-temperature environments require enhanced mechanical and tribological properties. In this research, different high chromium steels (Fe-Cr-C-Ni-Mo-Mn) have been coated over a 316L substrate using coaxial laser cladding. Optimized properties of the clad (such as adhesion, compactness, microstructure and dilution rate) have been obtained by a broad parameter search (laser power, powder feeding rate, scanning speed and preheating). Varying such parameters induces change in the microstructure, chemical distribution, morphology and properties of deposits. These have been thoroughly characterized in terms of metallurgical structure, phase compositions and functional properties using dedicated metallurgical mechanical and wear analysis. Samples obtained by laser cladding and plasma arc-transferred cladding have been compared. Laser cladding exhibits a significant strengthening mechanism for this hardfacing alloy. This results from a finer dendritic structure with a modified Chromium and Molybdenum precipitations distribution in the eutectic interdendritic phase.