Estimation of magnetic and rheological properties of MR polishing fluid and their effects on magnetic field assisted finishing process

Abstract

The finishing efficiency in magnetic field assisted finishing (MFAF) process mainly depends on the rheological properties of magnetorheological (MR) polishing medium. A detailed rheological study of MR polishing fluid at different volume concentration of fluid constituents and magnetic field is conducted to predict their contribution on yield stress and viscosity. Magnetic field has the highest contribution followed by carbonyl iron particles (CIPs) concentration to the yield stress and viscosity. It is observed that Herschel–Bulkley model better fits the rheological data than other two models. Also, it has been found that when total solid contents of MR polishing fluid exceeds more than 35%, there is a decrease in the yield stress. From magnetic characterisation, it is observed that saturation magnetisation increases with CIP concentration and decreases with abrasive concentration. The surface finish of stainless steel workpiece improves with an increase in the yield stress and viscosity at higher magnetic field and CIP concentration.