The effects of temperature and alloying elements on γ phase fraction of grain-oriented silicon steel,which contained 2.97-3.42mass% Si and 0.028-0.058mass% C,were studied by microstructure observation and statistics.Furthermore,the quantitative relationships of temperature as well as C,Si,and Mn contents to γ phase fraction were obtained by numerical fitting.The experimental results show that γ phase fraction firstly increases with increasing temperature,reaches a maximum and then decreases in the temperature range of 900-1 250 ℃.The temperature corresponding to the maximum γ phase fraction is about 1 150-1 200℃.Meanwhile,the γ phase fractions in steels at the same temperature have some differences because of different contents of various alloying elements.The verification results show that the values of γ phase fractions to C,Si,and Mn contents at the specific temperatures,which were obtained by multiple linear regression method,agree well with the measured values.In addition,the values of γ phase fractions to C,Si,and Mn contents in the temperature range of 900-1 250℃,which were obtained by binomial regression method,agree with the measured values when the contents of Mn and soluble Al are not more than 0.320mass% and 0.034mass%,respectively.The obtained equations can carry out the approximate prediction of γ phase fractions of grain-oriented silicon steels during the hot rolling process.
