Study on solidification organization and phase formation of Fe-6.5wt.%Si high silicon steel by arc melting and heat treatment

Abstract The solidification microstructure and phase formation behavior of Fe-6.5wt.%Si high silicon steel was investigated using arc melting and heat treatment. The alloy phase composition and microstructure were analyzed by XRD and SEM. The magnetic performance was measured at a high- and low-temperature vibration sample magnetometer. The results show that the temperature gradient causes alloy ingot to be roughly divided into three layers. With the decrease in temperature, from the bottom to the top, the phase morphology is fine crystals, columnar internal dendrites, and isoaxial internal dendrites. In the annealing ring ingot, the inner dendrites disappeared, and from the bottom to the top of the sample, the microstructure changed from fine crystal, columnar crystal, and isoaxial crystal, to micro-cracks, which first increased and then reduced. The hysteresis loop curve width of the alloy is narrow, the slope is large, the hysteresis is 0.126 emu/g, and the magnetic utilization after annealing decreases to 0.0667 emu/g, but the coercive force increases to 2.8 Oe/g, and the annealed alloy is more sensitive to the magnetic field and has a high magnetic conductivity coefficient.