Effect of cutting fluids on corrosion properties and turning surface quality of Fe-based superalloy

As the steam turbine rotor works in extreme conditions of high temperature, pressure, speed, and load, better material performance and machined surface quality are highly demanded. Fe-based superalloy is a kind of typical difficult-to-cut material that is widely used as steam turbine rotors, and cutting fluid is necessary during its machining process. However, many accidents occurred for the misuse of cutting fluids. The effect of cutting fluids on material characteristics and physical mechanical properties cannot be ignored. In this article, an experimental research was taken on the effect of cutting fluids on corrosion property and turning surface quality of a typical rotor material. Tafel curves, electrochemical impedance spectroscopy, surface morphology, and residual stress of machined surfaces were investigated. The results were explained integrating with physical and chemical properties of two cutting fluids. It indicated that the cutting fluid had an obvious effect on the corrosion property and machined surface quality of Fe-based superalloy. The material surface may be corroded after long-time exposure to cutting fluids. The lubricating property of cutting fluids has a great effect on surface morphology and residual stress, which may affect product lifetime and surface performance.