Abstract: A silicon steel was treated by using shot peening (SP) and followed by solid powder siliconizing treatment to investigate the possibility of simplify siliconizing operation by means of surface nanocrystallization and effect of siliconizing parameter. The microstructural evolution was examined by using transmission electron microscopy， scanning electron microscopy and X-ray diffraction， respectively. Experimental results showed that nanocrystallines (of about 10 nm in size) with random orientations form in the top surface layer of SP sample. After the siliconizing treatment in Si powder+halide at 550℃， a compound layer forms on the SP sample， and its thickness increases with the increasing of the siliconizing temperature and the duration at higher temperature， however keeps unchanged with the increment of halide content. The compound layer consists of FeSi and Fe₃Si phases. The higher temperature and halide content / lower temperature and halide content are helpful for the formation of FeSi/Fe₃Si phases， respectively.

Key words: silicon steel, shot peening, surface nanocrystallization, siliconizing, microstructure