通过热膨胀试验、金相显微组织观察等手段,研究了退火温度对汽车用DP440冷轧双相钢冷却过程中组织转变及静态曲线的影响。结果表明:随退火温度逐渐升高,奥氏体含量增加,铁素体含量减少。冷却过程中随冷却速率增加依次发生铁素体、贝氏体和马氏体相变。随退火温度升高,奥氏体向铁素体转变开始更迟。高的退火温度导致组织中的板条马氏体变得粗大。 The effects of annealing temperature on the microstructure and static curves during the cooling process of DP440 cold-rolled dual-phase steel for automobile were studied by means of thermal expansion test and metallographic microstructure observation. The results show that as the annealing temperature increases, the austenite content increases and the ferrite content decreases. During the cooling process, ferrite, bainite and martensitic transformation occur in turn with the increase of cooling rate. As the annealing temperature increases, the austenite to ferrite transformation begins later. High annealing temperatures cause the lath martensite in the tissue to become coarse.