通过对照显微结构与硼的自射线径迹显微照相（ＰＴＡ），研究了一种超低碳含硼钢在铁素体生长过程中硼分布的变化，发现：在发生等温铁素体相变前，硼已偏聚在奥氏体晶界上；铁素体在奥氏体晶界形核；在有铁素体生成的奥氏体晶界上，硼偏聚减弱；沿晶界长出的小块铁素体中硼浓度明显高于奥氏体，但随铁素体长大，其硼含量逐渐与母相持平。这些现象表明，铁素体长大不受硼在奥氏体中扩散的控制 The change of boron distribution in ferrite during the growth of a ultra-low carbon steel containing boron was investigated by comparing the microstructure with the self-scanning electron microscopy (PTA) of boron. It was found that when the isothermal ferrite phase Boron has been segregated on the austenite grain boundaries; ferrites nucleate at the austenite grain boundaries; Boron segregation decreases at austenite grain boundaries with ferrite; grain boundaries along the grain boundaries The boron concentration in the small pieces of ferrite is obviously higher than that of austenite, but with the growth of ferrite, the content of boron gradually becomes equal to that of the mother. These phenomena indicate that ferrite growth is not controlled by boron diffusion in austenite