Papers by Keyword: Magnetic Characterisation

Abstract: In this work the magnetic anisotropy of the 15Mo3 type steel was investigated which was induced by deterioration process caused by thermal shock fatigue. The applied thermal shock fatigue investigation can model the material degradation due to long term service in high temperature environment. The 15Mo3 steel is widely used as reheating pipeline base material of power plant boilers. Magnetisation curves were measured to characterise the induced magnetic anisotropy due to thermal shock fatigue process. A parallel motion vibrating sample magnetometer (PMVSM) which was designed at the Department of Materials Science and Engineering of BUTE was used for the magnetic measurements.

Abstract: A new type of vibrating sample magnetometer (VSM) was designed for measuring the magnetic properties of soft and hard magnetic materials is described. The developed instrument differs from the traditional Foner type because in our system the motion of the specimen is parallel with the lines of the external magnetic field. Therefore, this instrument can be called parallel motion vibrating sample magnetometer (PMVSM). The special vibrating system contains a vibrating rod which holds the specimen. This arrangement can make the sample replacement and positioning fast and convenient. Because of the versatility of the PMVSM instrument it could be a useful measuring device for materials science laboratory and educational purposes as well.

Abstract: Magnetic Barkhausen noise measurement (MBN) is a relatively new non-destructive detection technique. Its working principle is based on Barkhausen discontinuities or noise when a ferromagnetic material is subjected to a varying magnetic field. MBN is being used to characterise the stress state of a ferritic stainless steel (AISI 430). Other magnetic parameters such as saturation induction (BMax), remnant induction (BR), coercive field (HC) and maximal relative permeability (PMax) derived from the hysteresis loop have also been used to support the results achieved using MBN. Microstructural changes due to cold working and heat treatments were characterized by the applied magnetic measurements. The MBN technique was proved to be a useful non-destructive and quantitative method for microstuctural investigation of the investigated ferritic stainless steel.