Magnetic-abrasive treatment of flat surfaces of ferromagnetic parts with end heads based on high-energy magnets

A comprehensive study of the influence of the process of magnetic-abrasive machining (MAM) of ferromagnetic flat parts with end heads based on high energy magnets on the characteristics of the surface microprofile and residual stresses has been carried out. The study was carried out using magnetic abrasive powders of different grain sizes and shapes. The results of the research showed that, depending on the initial surface roughness, this process makes it possible to obtain the roughness parameter Ra in the range of 0.03 - 0.12 microns. The lower the value of the roughness parameter Ra obtained before the process of magnetic-abrasive machining, the lower the roughness formed after magnetic-abrasive machining. Such results are explained by the heredity of the machining, in particular by the size of the surface micro-roughness formed during the stages of pre-processing by milling and grinding. It has been shown that during the process of magnetic-abrasive machining, microplastic deformation of the surface layer of the products occurs, which leads to their riveting and the formation of residual compressive stresses in them. The magnitude of the residual compressive stresses depends on the size of the particles of the magnetic-abrasive powders and their shape. During the research, the highest stress values in the range of 75-165 MPa were obtained when using mainly rounded powders with a particle size in the range of 0.8-1.62 mm. In the case of magnetic-abrasive machining, it is possible to control the magnitude of internal stresses in the surface layer of parts by changing the size of the working gap, the duration of the machining time, the size and shape of the particles of magnetic-abrasive powders.