Experimental study on laser cladding forming of 316 L stainless steels based on Response Surface Methodology

In the realm of marine and coastal structures, laser cladding technology has demonstrated an immense potential in the structural and material repair. This study conducted a series of single-layer single-track laser cladding experiments on grade Q235 low-carbon steels, utilizing grade 316 L stainless steel powders under various laser powers, scanning speeds, and powder feeding rates. Subsequently, the process parameters were optimized based on the Response Surface Methodology (RSM). Furthermore, single-layer multi-track and multi-layer single-track laser cladding tests were performed to ascertain optimal overlap ratios, scanning patterns, and lifting amounts. Finally, the repair efficacy of optimized process parameters on corroded specimens was validated through standardized tensile testing. The results reveal that the laser power, scanning speed, and powder feeding rate significantly impact the formation quality and morphology of the cladding quality. Notably, the depth of the heat-affected zone (HAZ) increases proportionally with the increase in laser power and inversely with the decrease in scanning speed. Moreover, a well-matched powder feeding rate with laser energy is crucial to ensure a full and continuous morphology of the cladding tracks. Furthermore, the regression models were established, which exhibited a high predictive accuracy for the depth of the HAZ, the width-to-height ratio, and the dilution rate in laser cladding. The optimal parameters for single-layer single-track laser cladding were determined to be a laser power of 1405.9 W, a scanning speed of 12.68 mm/s, and a powder feeding rate of 0.7 rad/min. Finally, based on a comparative analysis of single-layer multi-track and multi-layer single-track laser cladding experiments, it is recommended that the overlap ratio should be maintained within the range of 31.58–42.11 %, and a lifting amount of 0.63 mm. The optimized process parameters significantly enhance the mechanical properties of corrosion-damaged specimens, enabling the repaired components to achieve or even surpass the performance benchmarks of intact (undamaged) counterparts.