The Effect On Microtexture Of Fine Grain High Strength IF Steel After Annealing

In this paper, the fine grain high-strength IF steels were adopted as tested steels.The annealing experiments were carried out by continuous annealing and laboratory simulated annealing two different process conditions. The microstructure and recrystallization texture orientations of tested steels were observed by OM, TEM, EBSD and other analytical techniques and the recrystallization texture orientation were analysed by OIM5.31 software. The influence to the tested steels of the microstructure and recrystallization texture which under different holding time in this two kinds annealing processes was comparative analysed. And then we can obtain the grain boundary character distribution of recrystallization texture during continuous annealing.The holding time of continuous annealing has a significant effect to the performance of the tested steels. For the carbon content of 0.007%, adding 0.1% Nb 1# tested steel, which is experimented by continuous annealing after cold rolling.When the annealing temperature reach 850℃, the holding time reach 120s, the test steel has a strong {111} texture and plastic strain ratio (r value) reach to the maximum value.It can be observed that extend the holding time has little effect on the ferrite organization of the 1# tested steel. For the carbon content of 0.043%, adding 0.097% Nb 2# tested steel, which is experimented by laboratory simulated box annealing after cold rolling.When the annealing temperature reach 850℃, the holding time reach 300s and 600s, the test steel has a strong {111} texture and the recrystallization texture near the < 111 > / / ND orientation with a high density. In both annealing process, the tested steel have taken place texture"diffuse phenomenon"with the change of holding time. And this"diffuse phenomenon"mainly transformed between {112} face texture and {111} face texture.When the annealing temperature of 1# tested steel after continuous annealing time reached 850℃,the holding time reached 120s, the tested steels received good texture .At the same time, the lowΣCSL andΣ13 total content of 1# tested steel is higher,the tested steel has better distribution characteristics of grain boundaries, the more superior deep-drawing performance and lower sensitivity of secondary working embrittlement.