Hi-B钢中抑制剂的析出行为

Precipitation Behaviors of Inhibitors in a Hi-B Steel

利用透射电镜和场发射扫描电镜研究了Hi-B钢热轧、常化和二次再结晶退火过程中抑制剂的析出情况,研究表明:热轧后抑制剂沿板厚度方向存在梯度分布现象,即表层再结晶组织、次表层(过渡层)、中心层形变组织中析出相尺寸和体积百分数存在差异;常化处理不会改变析出相的分布,但促进了AlN的析出,且调整了析出相尺寸的分布;在二次再结晶退火过程中,N2/H2混合气氛下,抑制剂不易熟化、分解,一直保持强的抑制效果,致使二次再结晶开始温度滞后至1013℃。

The precipitation during hot-rolling,normalization and secondary recrystallization annealing in a Hi-B steel containing MnS and AlN as inhibitors was investigated by TEM and SEM.The results show that the distribution of precipitates and their volume fraction changed along the thickness of hot-rolled sheet.The distribution of precipitates in three typical layers,which were the surface layer with completely recrystallized microstructure,the subsurface layer（or transition layer）and the center layer with deformed structure,respectively,was discussed.The normalization process after hot rolling did not change the distribution of precipitates but promoted new fine AlN to appear and kept precipitates in suitable size to exert strong Zener pinning force.The number of inhibitors kept constant and AlN particles were not easy to discompose due to the N2 from protecting atmosphere during secondary recrystalliztion annealing,which led to postpone the onset temperature of secondary recrystallization to 1013℃.