Abstract: The Effects of the elements of Ti and S on the second phase precipitates of high grade non-oriented silicon steels in equilibrium state and mass production have been studied. The results showed that the precipitation starting temperature and stable precipitation amount of Ti（C,N) and MnS were both increased as the increase of the contents of Ti and S in equilibrium state.While in industrial production, the average sizes and area densities of the two precipitates in normalized plate’s samples with high Ti and low S contents were both higher than the samples with low Ti and high S contents, but in finished plate, it can be seen that the two precipitates’ average sizes and area densities in the samples with high Ti and low S contents were both lower than the samples with low Ti and high S contents.

Key words: non-oriented silicon steel, precipitate, precipitation temperature, stable precipitation amount