在传统600 MPa级双相钢成分的基础上，通过适当降低铬、钼元素的含量，设计了中温卷取型热轧双相钢的化学成分，采用热模拟试验研究了试验钢的动态连续冷却转变行为；根据热模拟结果对热轧卷取工艺进行优化，并进行现场工业试制，研究了优化前后的显微组织和性能。结果表明：当冷却速率大于15 ℃·s^-1时，试验钢显微组织主要由贝氏体、马氏体和少量铁素体组成，且随着冷却速率的增大，贝氏体由粒状变为板条状，马氏体含量增加；采用优化的中温卷取全程密集冷却工艺生产的热轧双相钢较优化前的晶粒更细小，马氏体含量更高；采用优化工艺生产的热轧双相钢的屈服强度、抗拉强度、硬度均高于优化前的，断后伸长率和扩孔率均低于优化前的，但仍满足标准要求，说明试制的热轧双相钢具有良好的综合力学性能。

The chemical composition of medium temperature coiling type hot-rolled dual phase steel was designed by appropriately reducing the content of chromium and molybdenum elements on basis of the composition of traditional 600 MPa grade dual phase steel. The dynamic continuous cooling transformation behaviour of the test steel was analyzed by thermo-simulation. The hot-rolled coiling process was optimized according to the thermo-simulation results, and a trial industrial production was conducted. The microstructure and properties before and after optimization were studied. The results show that when the cooling rate was greater than 15℃·s^-1, the microstructure of the test steel mainly consisted of ferrite, martensite and a small amount of bainite; with the increase of cooling rate, bainite changed from granular to lath-shape, and martensite content increased. The grains of hot-rolled dual phase steel produced by optimal medium temperature coiling whole intensive cooling process was finer than that before optimization, and martensite content was higher. The yield strength, tensile strength and hardness of hot-rolled dual phase steel produced by optimal process were all higher than those before optimization; percentage elongation after fracture and hole expansion rate were both lower than those before optimization, but still satisfied the standard requirement, indicating that trial-produced hot-rolled dual phase steel had good comprehensive mechanical properties.