Study On The Behavior Of Recrystallization And Second Phase Precipition Of Rare Cold Rolled Steel Plate By CSP Process

CSP (Compact Strip Production) technology is widely used in automotive filed in recentyears due to its low cost, high efficiency, energy saving and economic benefit, but the deepdrawing property of cold rolled plates by CSP for automobile sheet needs to be improvedbecause of its high yield ratio, so taking advantages of the CSP as the same as reasonablecontrolling parameters of batch annealing process in order to improve microstructure andtexture become heavily attractive subject of iron factories and research institutions.In this paper, batch annealing process was simulated by taking rare cold rolling platesunder CSP process conditions as main research object in the laboratory. The evolution ofmicrostructure and texture as well as behaviors of precipitated phases at the different rateduring heating also have been system investigated by scanning electronmicroscopy(SEM),X-ray diffraction(XRD),electron backscattering diffraction (EBSD) andchemical quantitative method of analysis.The results in three different batch annealing process show that it was easy torecrystallize as the temperature was from470℃to530℃at80C/h compared with40/h, and the recrystallization process was faster than that of at the same heating rate from470℃to630℃, also, the analysis on XRD indicate that the density of texture increased asthe hating rate especially for the texture that we hope during heating after recrystallizationoccurring, but when the hating rate is over80C/h, the density difference of {111}<011>and {111}<112> could become large up to about1.2.In the best batch annealing process, it was applied that by chemical quantitative analysisthe AlN precipitation amount in the final batch annealing is about2times as high as that ofhot rolled at670℃, the precipitation of AlN were promoted by the addition of rare earthelement at670℃; it was observed by EBSD that the {011}<100> and {112}<110>orientation exist near the {110}<112> orientation at570℃,and the competition growth ofgrains with {110}<110> and {111}<110> orientation were brought before670℃; Thegrain {112}<110> and {001}<110> orientation are the main orientation but not {110}<110> after670℃.