Modeling of melt pool and thermal field simulation for wide-band laser cladding

The accuracy of thermal analysis modeling for direct energy deposition is compromised if the Marangoni effect is ignored. The anisotropic enhanced thermal conductivity approach can improve the fidelity of the transient finite element (FE) thermal model, but the determination of the enhanced factors is generally based on empirical knowledge or trial and error. In this study, single track cladding experiments were conducted at different process parameters, the cladding process was recorded by an infrared camera, and the melt pool width and length were extracted from the infrared images. The best match enhanced factors were confirmed according to the comparison between the simulated and experimental melt pool sizes. The findings suggest that the best match enhanced factors are not a constant value, but rather vary with changes of process parameters. With the enhanced factors increasing, the peak melt pool temperature drops sharply at first and then tends to be stable. The melt pool width remains almost unchanged, whereas the melt pool length exhibits a slight increase. Laser specific energy was found to be a suitable metric to characterize the convection features and intensity of the melt pool. An empirical model of laser specific energy and enhanced factors was derived through linear regression analysis, which greatly simplified the determination of the enhanced factors. The experimental results showed that the error of the FE thermal model in predicting the melt pool size was less than 6.3%.