以工业生产的240 MPa级高强IF钢为试验材料, 进行了冷轧压下率和退火温度的实验室研究。结果表明: 在试验条件下, 不同退火温度下, 冷轧压下率在75%～85%时, 试验钢为完全再结晶组织, 卷取温度较高在710 ℃的试验钢的屈服强度、抗拉强度、伸长率、屈服点伸长率、塑性应变比及应变硬化指数分别在260 MPa, 445 MPa, 37.5%, 2.14%, 0.25, 2.0左右; 卷取温度较低在670 ℃的试验钢的上述参数分别为235 MPa, 369 MPa, 38.8%, 1.73%, 0.26, 2.1左右。最终提出了试验钢工业生产中退火温度为840 ℃左右, 冷轧压下率为75%左右, 为获得高强度和优良成型性能的最佳匹配。

Hot rolled 240 MPa grade high strength IF steel sheet was used to study of cold reduction ratio and annealing temperature of experimental steel. The experimental results showed that the recrystallization had finished under different annealing temperature followed 75%-85% cold reduction ratio. To the experimental steel of high coiling temperature 710 ℃, the yield strength, tensile strength, elongation percentage, yield point elongation, plastic strain ratio and strain hardening exponent were approximate 260 MPa, 445 MPa, 37.5%, 2.14%, 0.25, 2.0. To the experimental steel of low coiling temperature 670 ℃, that were approximate 235 MPa, 369 MPa, 38.8%, 1.73%, 0.26, 2.1.Therefore, the suggested optimal annealing temperature is 840 ℃, cold reduction ratio is 75%, and it obtains optimally match of high strength and punching property.