高Nb-Ti新能源汽车用无取向硅钢热轧过程的再结晶行为

Recrystallization behavior during hot rolling of high Nb-Ti non-oriented silicon steel for new energy vehicle

利用蔡司显微镜和Nano Measurer金相分析软件,研究了不同加热温度下新能源汽车用高Nb-Ti无取向硅钢显微组织的演变规律,并利用ICP-MS对不同加热温度下Nb、Ti的固溶量进行检测分析;然后采用热模拟方法研究了热轧过程中试验钢的再结晶行为。结果表明:随着加热温度升高,试验钢的晶粒尺寸增加明显,而Nb、Ti的固溶量仅略有增加。当加热温度为1230℃、变形温度分别为1100、1050、1000℃时,在应变速率0.1 s^(-1)、变形量30%和应变速率1 s^(-1)、变形量80%的条件下单道次压缩后的试验钢均未发生动态再结晶行为,而在应变速率为1 s^(-1)、变形量为40%的条件下,在1100℃及1050℃单道次压缩后再保温30 s以上时有静态再结晶行为发生,显微组织大部分为等轴晶粒,但是在1000℃变形单道次压缩后再保温50 s的显微组织仍以未再结晶的长条晶粒为主。

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.