Multi-Objective Optimization of Laser Cladding Parameters for Stellite 12 Coatings Using Central Composite Design (CCD)

The research investigates the influence of laser-cladding parameters in WC9 steel-surface multi-track Stellite 12 alloy coatings. Mathematical models of penetration depth, grain size, and microhardness in the coating were developed by Central Composite Design with altering of the input laser power, scanning speed, powder feed rate, and overlapping rate. Response Surface Methodology was used to analyze the correlation of different processing parameters affecting the selected responses. A coating with penetration depth was achieved by significantly reducing the laser power and overlap ratio while increasing the powder feed rate. Appropriately reducing the laser power while increasing the powder feed rate effectively refined the grain size of the Stellite 12 alloy coating. Higher microhardness in the coating was obtained by appropriately increasing the powder feed rate and scanning speed while reducing the laser power. Afterwards, a desired processing parameters set was obtained through optimization with the target of minimizing the penetration depth and grain size and maximizing the microhardness. Experimental validation with this processing parameter setup provided satisfactory coating, and the error rate for the penetration depth, grain size, and microhardness was 9.66%, 7.36%, and 5.46%, respectively. This paper provides the theoretical guidance for the prediction and control of the penetration depth, grain size, and microhardness in WC9 steel-surface multi-track laser cladding with the Stellite 12 alloy.