Effect of Laser Spot Diameter on Melt Pool Thermal History During Laser Cladding on Inconel 718 Coatings

Abstract

AbstractLaser cladding is a surface coating technique used to repair the worn-out components. In this work, effect of laser spot diameter on the melt pool thermal history during laser cladding on Inconel 718 substrate is studied using finite element-based numerical modeling. COMSOL Multi-physics heat transfer module is used for analysis. Six different laser spot diameters of varying size from 1 to 6 mm are considered in the study and the results are compared. The results show that, increase in spot diameter reduces the melt pool temperature, as about 45% reduction in temperature is observed as the spot diameter increases from 1 to 2 mm and further the temperature difference reduces with increase in diameter. The substrate melting was not observed for larger diameters which indicate the absence of metallurgical bond (no cladding) formation with the substrate, whereas the rapid heating observed in all the samples, and a decrease in rapid cooling of the melt pool is noticed with increase in laser spot size; this could be due to decrease in the energy density. Also, the melt pool size is smaller for low spot diameters, due to the dominant radiation over conduction which results of high surface temperatures. The overall analysis suggests that high powers must be incorporated for laser cladding with larger spot diameters and vice versa.KeywordsLaser claddingNumerical analysisThermal historyLaser spot diameterCOMSOL+