中文摘要：

观察了不同冷速下获得的含Ti非调质钢的显微组织,并绘制了静态连续冷却转变曲线（CCT曲线）。结果表明,在0·5-2·5℃/s的冷速范围内,会有晶内铁素体析出,其中在2℃/s冷却时可以获得大量针状铁素体。空冷条件下获得细小无序分布的晶内铁素体,明显提高试验用含Ti非调质钢的韧性。

英文摘要：

：The microstructure of Ti-containing non-quenched and tempered steel obtained at different cooling rates was studied, and the continuous cooling transformation（CCT） diagram of the tested steel was also obtained. The results show that, at the cooling rate range of 0.5 ℃/s - 2.5℃/s, multiple intragranular ferrite forms, while at the rate of 2 ℃/s, the microstructure is mainly acicular ferrite. And by air cooled ,the tested Ti-containing non-quenched and tempered steel obtains fine and chaos intragranular ferrite,which improves the toughness greatly.