FEATURES OF FORMATION OF THE “KEY HOLE” DISINTEGRITY DEFECT IN LPBF TECHNOLOGY

The paper studies the influence of laser melting parameters of 316L powder material on the shape of the melt pool and the formation of Key Hole defects. Analysis of 808 tracks revealed 46 cases of porosity. Despite the considerable attention of researchers to LPBF processes, the transition from the conduction mode to the Key Hole mode remains controversial and insufficiently studied. This emphasizes the complexity of the physical phenomena occurring in the melt pool and the need for further research. Analysis of the obtained results showed that Key Hole defects do not always appear at the maximum depth of the melt pool. It was found that porosity can form in a wide range of powers, but these defects are observed only at scanning speeds less than 600 mm/s.