关键词: 表面完整性, 残余应力, 镍基高温合金, 预应力切削

Abstract: In view of the serious residual tensile stress distribution on the machined surface in cutting nickel-based super-alloy, the utilization of prestressed cutting method is proposed to actively control the residual stress distribution status on the machined surface in machining process. Nickel-based super alloy shafts are pre-stretched at the condition of 0 MPa, 150 MPa and 300 MPa by a lathe-specific pretension device respectively. A comparison experiment with cemented carbide cutter cutting nickel-based super-alloy in three conditions of prestressed turning is carried out. The cutting force, chip formation and surface integrity indexes including residual stress on machined surface, surface roughness, surface topography and micro-hardness are compared and studied. The results show that in certain extent suitable compressive residual stress on machined surface are achieved by utilizing the prestressed cutting method; meanwhile procedures of residual stress adjustment after machining can be omitted. Furthermore, the magnitude of compressive residual stress can be actively controlled by adjusting the magnitude of prestressed force. To compare with normal cutting process, uniform saw-tooth chip are generated in pre-stressed cutting, meanwhile there’s no significant increment of cutting force. Prestressed cutting method can generate good surface integrity without any additional hardening.

Key words: Nickel-based superalloys, Prestressed cutting, Residual stress, Surface integrity