Abstract: The effect of curling temperature on the mechanical properties of Ti microalloyed high-strength steels was investigated using electron backscatter diffraction， transmission electron microscopy， scanning electron microscopy and mechanical experiments.The results show that with the increase of curling temperature， the grain size and the proportion of small-angle grain boundaries of steel increase， while the large-angle grain boundaries and dislocation density decrease. When the curling temperature increases from 595 ℃ to 625 ℃， the tensile strength of the steel decreases by 4%， the elongation increases by 32%， and the low temperature impact toughness decreases by 53%. The migration and elimination of large-angle grain boundaries and the increase of grain size ， the reinforcement of fine grain strengthening is weakened thus reducing the strength and low temperature toughness of steel. The increase of the proportion of small-angle grain boundaries in steel and the decrease of dislocation density effectively prevents the propagation of cracks and the occurrence of brittle fracture， thus improving the plasticity of steel.When the curling temperature is 610 °C， the tensile strength and low-temperature impact toughness of the steel do not decrease significantly， and the steel has a high elongation. With the ongoing increase in the coiling temperature， there is a substantial reduction in the strength and low-temperature impact resilience of the steel.

Key words: Curling Temperature, Ti Microalloyed Steel, High Strength Steel GCL700, Tensile Properties, Impact Toughness, Microstructure

摘要： 采用电子背散射衍射、透射电镜、扫描电镜和力学实验研究了卷曲温度对Ti微合金高强钢力学性能的影响。结果表明，随着卷曲温度的增加，钢材的晶粒尺寸和小角度晶界占比增加，大角度晶界和位错密度下降。卷曲温度从595 ℃升高到625 ℃，钢材的抗拉强度降低了4%，伸长率增加了32%，低温冲击韧性下降了53%。大角度晶界的迁移和消除以及晶粒尺寸增加，细晶强化作用减弱，从而降低了钢材的强度和低温韧性。钢中小角度晶界占比的增加和位错密度的下降则有效防止了裂纹的扩展和脆性断裂的发生，进而提高了钢材的塑性。在卷曲温度为610 ℃时，钢材的拉伸性能和低温冲击韧性没有明显下降的同时，且钢材具有较高的伸长率。继续增加卷曲温度，钢材的强度和低温冲击韧性显著下降。

关键词: 卷曲温度, 钛微合金钢, 高强钢GCL700, 拉伸性能, 冲击韧性, 微观组织