Numerical Transient Heat Transfer Analysis of Multi Laser Track on Powder Bed of Ni-Based Alloy

The numerical transient heat transfer analysis is conducted for SLM process of Ni-based alloy. For the initial situation, the powder layer covers all the top surface of bulk substrate. Then it is simulated a laser spot scans one and half times of round trips. To simulate the melting of powder layer and its solidification, the powder elements are changed to the bulk when the powder element’s temperature reaches to liquidus. The results show the change in melt pool shape. It is symmetry about scanning direction axis for the first path, but the second and third paths’ melt pool is wider on the solidified side. The melt pool dimensions are compared with the experimentally obtained thermography images. The estimated melt pool depth is also compared with the metallographic microstructure image of cross section. The results might suggest the one-path simulation is not enough for the prediction of solidified track of SLM process.