Anisotropic magnetic properties of milled bearing steel surface

Abstract

For many reasons, the steel surfaces are machined to obtain required physical properties. Suitable methods are required for the management and control of the manufacturing processes, which are simultaneously sufficiently robust and sensitive. The non-destructive testing methods, sensitive to the magnetic properties of the surface, are very suitable for this purpose. The Barkhausen noise (BN) measurement, which reveals the discontinuous movement of the magnetic domains in the thin surface layer during magnetisation reversal process is very robust, while magneto-optical Kerr effect (MOKE) method, using polarized light for orientation measurements of magnetic domains at the surface, is very sensitive and provides detailed information about hysteresis curves (HC) of the materials. In this contribution our results obtained on the milled 100Cr6 bearing steel are presented. These properties were obtained by MOKE laboratory measurements and bring very interesting facts about the magnetisation reversal process, which depends on the orientation of the magnetic field with respect to the cutting direction. Our results clarify the strong anisotropy of BN, which is observed during the industrial application of this method.