Nb-Ti高强IF钢板最优再结晶退火温度确定

Determination of Optimal Recrystallization Annealing Temperature of Nb-Ti Microalloying High Strength IF Steel

以工业生产的Nb-Ti高强IF钢为试验材料,在实验室研究了退火温度对试验钢的显微组织、力学性能和织构的影响。结果表明:在试验条件下,退火温度750℃时,试验钢为未完全再结晶组织,退火温度升高至780～870℃时,试验钢均为完全再结晶组织;随着退火温度的升高,试验钢的ReL、Rm逐渐降低,A50、Ae逐渐增加。退火温度810～840℃时,试验钢的屈服强度、抗拉强度、延伸率、塑性应变比及应变硬化指数分别在300 MPa、410 MPa、36.5%、1.7、0.22左右;随着退火温度的升高,α和γ取向线织构减弱。且织构有向{111}织构靠拢的趋势。提出试验钢工业生产中的最佳再结晶退火温度为810～840℃。

The Nb-Ti microalloying high strength IF steel sheet was used to study the effect of annealing temperature on the microstructures,mechanical property and textures.The experimental results showed that experimental steel was incomplete recrystallization when annealing temperature is 750 ℃,and the recrystallization has finished when annealing temperature was from 780 ℃ to 870 ℃ under experimental condition.With the increasing of annealing temperature,the yield strength and tensile strength gradually reduced,and the the plastic strain ratio and yield point elongation gradually increased.The yield strength,tensile strength,elongation percentage,the plastic strain ratio and the strain hardening exponent were approximate 300 MPa,410 MPa,36.5%,1.7 and 0.22 under annealing temperature 810 ℃ to 840 ℃.When the annealing temperature was increased,the α textures and γ textures were gradually weakened,and the α textures have a trend of close to texture {111}.Therefore,the suggested optimal recrystallization annealing temperature of industrial production is 810 ℃ to 840 ℃.