Inconel®718 superalloy machinability evaluation after laser cladding additive manufacturing process

Additive manufacturing is being introduced in industry during the last years being laser cladding one of the most representative technologies. Laser cladding is usually combined with machining in hybrid processes in order to obtain tolerance and finishing requirements. Therefore, added material must be machined and material properties need to be evaluated for a high quality machining operation execution. In this paper, laser deposited Inconel®718 alloy machinability properties are evaluated. The work is focused on hybrid processes of laser cladding build up geometries that require final machining operations such as turning and milling for final part obtaining. Inconel®718 machining behavior is analyzed for turning and milling operations. Turning tests are carried out for different cutting speed values (60, 80, and 100 m/min), cutting speed values (0.1, 0.2, and 0.4 mm), and depth of cut values (0.1, 0.2, and 0.3 mm/rev). Milling tests are also performed for different machining parameters such as axial depth of cut (20, 15, 10, and 5 mm), radial cutting depth (0.1, 0.3, and 0.5 mm), cutting speed (depending on the average diameter for each axial cutting depth), and feed per tooth (0.05 and 0.06 mm/tooth). For both processes, the material is studied in three different states, that is, base material (heat treated), added material as deposited (i.e., without final heat treatment), and deposited and treated material (with final heat treatment). In all cases, machinability properties such as cutting forces, specific cutting energy, material roughness, and microhardness values are evaluated. Obtained study results are discussed in the last section.