利用热模拟试验机、实验室轧机、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HR-TEM)等设备系统研究了Ti微合金热轧带钢连续冷却相变规律、组织和性能随卷取温度的变化规律及强化机理。建立了试验钢的动态CCT曲线。研究结果表明：当冷速小于1℃/s时，试验钢中奥氏体发生铁素体-珠光体相变。当冷速为5~10℃/s时，既发生铁素体-珠光体相变又发生贝氏体相变，贝氏体相变温度约为600℃；当冷速为20~50℃/s时，试验钢仅发生贝氏体相变，且随着冷速的增加钢中的贝氏体逐渐由粒状贝氏体向板条贝氏体转变。此外，对不同卷取温度下试验钢组织和性能的研究表明，随着卷取温度的降低试验钢的强度和塑性均有所提高。当卷取温度为550℃时，试验钢的力学性能最优，其抗拉强度、屈服强度和断后伸长率分别为742 MPa、683 MPa 和22·5％，主要是由于晶粒细化和纳米级TiC析出所致。
The continuous cooling transformation behavior,the effect of coiling temperature on microstructure and mechanical properties,and strengthening mechanisms of Ti microalloyed high strength hot strip steel were sys-tematically investigated by thermal simulation testing machine,laboratory rolling mill,SEM and HR-TEM.The dynamic CCT curve was established.The results show that the austenite to ferrite and pearlite transformation takes place when the cooling rate is less than 1℃/s.The austenite to bainite transformation accompanied with aus-tenite to ferrite and pearlite transformation takes place when the cooling rate is in the range of 5 ℃/s to 10 ℃/s.The bainitic transformation temperature is about 600℃.The amount of granular bainite decreases,while the amount of lath bainite increases with the increase of cooling rate in the range of 20℃/s to 50℃/s.Furthermore,the study on the effect of coiling temperature on the microstructure and mechanical properties of experimental steel has shown that the strength and plasticity of tested steel are improved with decreasing the coiling temperature.When the coi-ling temperature is 550℃,the experimental steel possesses optimal mechanical properties owing to the grain re-finement and precipitation of nano-scale TiC particles.And the tensile strength,yield strength and elongation of tested steel were 742 MPa,683 MPa and 22·5%,respectively.
参考文献
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%