Texture Evolution And Its Influence On Deep Drawability Of IF Steel Containing Nb And Ti

The product process of IF steel containing Nb and Ti was simulated by cold rolling test machine and continuous annealing testing machine.The type and content of texture and the deep drawablity of IF steel were investigated by EBSD,X-Ray diffraction and tensile tester.The quantitative analysis methods of texture of IF steel were discussed.The evolution and relationship of texture and deep drawability during cold rolling and annealing process were studied.The results are shown as follows:(1)When determining the texture of cold rolled sheet by XRD,the surface condition of sample is extremely important.The surface should be fine polished to ensure the accuracy of quantitative results.(2)During the hot rolling coiling stage,all the types of texture are weak,and both theγ-fiber and α-fiber intensities are increased during the cold rolling process.The a-fiber gradually transform to y-fiber after annealing.With increase of the cold rolled reduction ratio,the content ratio of {111} texture to {100} texture and the r value are both gradually increase in annealed plate.The n value increases firstly and then decreases.(3)As increasing annealing temperature,the content ratio of {111} texture to {100}texture and the r value are increased while the n value with little change increases firstly and decreases later.With the addition of soaking time,the content of {111} texture increases while that of {100} texture decreases.The nonlinear increase of the content ratio of {111}texture to {100} texture is observed,which indicates the similar variation tendency with the r value.A little nonlinear reduction of the n value is obtained as the increasing a soaking time.(4)The mechanism of oriented nucleation could explain formation of recrystallization texture in IF steel.The new {111}<110>grains preferred form in the deformation matrix of{111}<112>during the recrystallization annealing process.The deformation matrix of{111}<112>constantly reduces as the growth of {111}<110>grains.Then,the new{111}<112>grains occur in the deformation matrix of {111}<110>and the matrix is gradually consumed.As the addition of the annealing temperature and soaking time,the increase rate of the texture content of recrystallization {111}<110>is faster than that of{111}<112>because of the cross nucleus and the recrystallization effect.This paper showed that the mechanism of oriented nucleation could explain formation of recrystallization texture in IF steel very well.The influence law on texture and deep drawing properties of IF steel by cold rolling reduction,annealing temperature and soaking time were obtained,respectively.These conclusions can be used for reference in the field of cold rolling and annealing processes on IF steel.