Abstract: The precipitations of non-oriented silicon steel produced by CSP were investigated by use of Tecnai F20 TEM with X-ray energy spectrum analyzer. The results showed that, the precipitates of aluminum free steel（the mass fraction of Al less than  0.01 %）50W1300 and 50W800 are mainly Cu_XS/MnS, while the precipitates of the silicon steel 50W1300 and 50W800 containing aluminum,are not only Cu_XS/MnS, but also much Ti (CN) and AlN precipitates. The average size of the precipitates in 50W1300 and 50W800 without aluminum is 51 nm and 90 nm respectively, which is obviously smaller than the average size of 50W1300 and 50W800 contained aluminum of  69 nm and 182 nm.

Key words: CSP, non-oriented silicon steel, precipitates