MAGNETIC CHARACTERISATION OF PHASE TRANSFORMATIONS IN TRIP STEELS

István Mészáros

   In the present work the microstructure and the strain induced phase transformation of TRIP steel were studied. Sheet samples were elongated in a tensile testing machine. The number of samples was eighteen; the applied deformation was up to 28%. The magnetization curves were measured by a single sheet tester-type magnetic property analyzer. The series of symmetrical minor hysteresis loops and the saturation loop were measured. Our novel data evaluation technique was applied for data evaluation of the magnetic measurements. This method is based on the multiphase-hyperbolic model of magnetization and it is called model based data evaluation (MBDE) technique. The MBDE method allows us to separate the magnetic contribution of different magnetic phases of the tested alloy. The magnetic contribution of ferrite, bainite and martensite phases were determined. Not only their relative phase ratios can be determined by this unique phase decomposition method but the magnetization curves of the individual contributory phases, can be calculated as well. The application of model based data evaluation technique (MBDA) seems to be a promising and sophisticated data evaluation tool in magnetic measurements.

Keywords: hysteresis, modelling, magnetic measurements, phase separation, mlticomponent-hyperbolic model, TRIP steel

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