Friction property and milling machinability of Ni60 cladding layer in hybrid additive-subtractive manufacturing

Hybrid additive-subtractive manufacturing (HASM) is an advanced technology for parts repairing. However, the complex process and difficult to machine characteristics of cladding formed materials limit its applications. The microstructure, friction property, and milling machinability of the single-pass laser cladding layer (LCL) are investigated using laser cladding and milling experiments. The results show that Ni60-based LCL has a good forming quality on the Cr12MoV die steel. The average micro-hardness of LCL is 1.38 times that of substrate and the wear mechanism is mainly the mixture of oxidation wear and abrasive wear. Furthermore, the results of multi-zone milling experiment show that the saw-tooth chips have been appeared at the milling speed of 75.4 m/ min. On the other hand, the results of single-zone milling experiment show that the middle zone has the lowest average value of and fluctuate of milling force, and has the best machined surface quality. Moreover, the micro -hardness after milling in the middle zone can reach to 57 HRC, and its wear resistance is 20.93 % better than that of substrate. Therefore, the middle zone of LCL has the best machinability, and the subsequent processing is eager to be carried out in this zone. A guiding concept of cladding parameters selection is proposed based on the machinability and machining position. It is of great significant to improve the machining efficiency and machining quality of HASM process.