Research On The Precipitation Behaviors Of Inhibitors In Cu-containing Low Temperature Oriented Silicon Steel During Hot Rolling Process

The development of modern society is inseparable from the important energy of electric power.Oriented silicon steel is an important soft magnetic material in the power system,which has excellent magnetic properties in the rolling direction.This is mainly due to the strong Goss texture in the finished oriented silicon steel.One of the conditions for obtaining the sharp Goss texture is the existence of fine dispersed second particle in the steel to inhibit the growth of the primary grain.MnS and AlN are mainly used as inhibitors in the traditional process of producing oriented silicon steel at high temperature.Therefore,the low-temperature oriented silicon steel with Cu₂S as the main inhibitor is gradually popularized.At present,it is known that Cu₂S particles mainly precipitate in the hot rolling stage,but the precipitation behavior of inhibitors in each pass of the hot rolling process is less studied.In this paper,by means of simulated hot rolling experiment,the precipitation of inhibitor in each pass during hot rolling is studied,which provides certain data support and theoretical guidance for the improvement of hot rolling process.This paper mainly relies on the hot rolling process of low temperature oriented silicon steel containing Cu in a domestic steel plant.Through the calculation of thermodynamics and dynamics,the precipitation of inhibitors in the experimental steel was analyzed simply,and the hot rolling simulation experiment of two component oriented silicon steel was carried out in the laboratory through two high rolling mill,and the slab heating simulation experiment was carried out through the box furnace.The precipitation behavior of inhibitor in experimental steel was studied by transmission electron microscope,the microstructure evolution behavior of experimental steel was observed by Zeiss metallographic microscope,and the distribution of Gauss grain and grain boundary in experimental steel after rough rolling was analyzed by EBSD.The results show that the main inhibitors produced in the hot rolling process are Cu₂S,MnS and?Cu,Mn?s.It can be seen from the theoretical calculation that MnS precipitates preferentially at high temperature and Cu₂S precipitates mainly at low temperature.During rough rolling,with the increase of rolling passes,the microstructure is gradually refined and the thickness direction is not uniform.After rough rolling,there are more Gauss grains in the sub surface layer to 1/4 layer.In the process of simulated rough rolling,the density of inhibitor surface increases with the increase of rolling passes,and it increases most in the second and third passes of rough rolling.After the completion of rough rolling,the density increases to 4.36×10⁸/cm²,and the increase of inhibitor size is not significant.In the process of simulated finish rolling,the type of inhibitor remains unchanged,the area density increases with the increase of rolling passes,and slowly increases to 5.38×10⁸/cm² after finishing rolling,and the size of inhibitor does not change much.The addition of trace rare earth Ce delayed the recrystallization of the experimental steel,increased the recovery structure of the experimental steel,decreased the recrystallization grain size,increased the sub surface Gauss grain size,and decreased the brass grain size.At the same time,rare earth Ce also makes the size of inhibitor decrease,the amount of?Cu,Mn?s increased,and the area density of inhibitor increases with the addition of rare earth.