Abstract: Microstructure evolution of high Nb-Ti non-oriented silicon steel for new energy vehicle at different heating temperatures was studied by using Zeiss microscope and Nano Measurer metallographic analysis software, the dissolved amounts of Nb and Ti at different heating temperatures were measured and analyzed by ICP-MS (Inductively coupled plasma mass spectrometry), and then the recrystallization behavior of the steel during hot rolling was studied by means of thermal simulation. The results show that the higher the heating temperature, the more significant the increase in the grain size, but the dissolved amounts of Nb and Ti only slightly increase. When heating at 1230 ℃ and deformed at 1100, 1050, 1000 ℃ respectively, the steel has no dynamic recrystallization behavior after single pass compression with deformation of 30% at strain rate of 0.1 s^-1 or with deformation of 80% at strain rate of 1 s^-1. However, when holding for more than 30 s after single pass compression of 40% at 1100 ℃ and 1050 ℃ respectively under strain rate of 1 s^-1, static recrystallization behavior occurs and the microstructure of the steel is mostly isoaxial equiaxial grains, but the microstructure is mainly of elongated unrecrystallized grains when holding even for 50 s after deformation at 1000 ℃ with the same condition.

Key words: new energy vehicle, non-oriented silicon steel, heating temperature, recrystallization, softening rate