罩式退火无间隙原子钢的最优冷轧压下率的确定

以工业生产的含钛、铌和含钛的两种无间隙原子(IF)钢热轧钢板为试验材料,在实验室研究了冷轧压下率对两种IF钢的显微组织、力学性能和再结晶织构的影响。结果表明:在试验条件下,两种试验钢经不同冷轧压下率冷轧和720℃×5 h罩式退火后,再结晶完成,随着冷轧压下率的增加,晶粒变得细小均匀,退火后得到的织构也增强,并且织构类型有转向{111}织构的趋势;塑性应变比r90在压下率为70%时达到最大值,随着冷轧压下率的进一步增大,r90值减小;应变硬化指数n90值逐渐降低。最后提出工业生产中冷轧压下率最佳范围为70%~80%,可获得良好的深冲性能。

Determination of Cold Reduction Ratio of Batch Annealing IF Steel

Two kinds of hot rolled IF steel added with Ti and Nb or added with Ti used to study the effect of cold reduction ratio on the microstructures, mechanical properties and textures of IF steel. The results showed that the IF steel was recrystallize finished after cold rolling follow different cold reduction ratio and batch annealing（annealing temperature 720 ℃ and soaking time 5 h） under experimental condition. When the cold reduction ratio was increased, the grain changed fine and uniformity; the texture of IF steel was stronger, as the textures had a trend with {111} texture. The plastic strain ratio r90 value reached the maximum with cold reduction ratio of 70%, when the cold reduction ratio was increased, the r90 value was gradually reduced; however, the strain hardening exponent n90 value was gradually reduced. Finally, it was suggested that the optimal cold reduction ratio was 70%~80%, consequently that can obtain good deep punching property.