加热温度对微合金高强钢奥氏体组织及其再结晶的影响

Effect of Holding Temperature on Microstructure and Recrystallization of Austenite in Nb-V-Ti Microalloyed High Strength Steel

通过实验室模拟实际生产中的加热过程及单道次压缩热模拟试验,结合组织观察分析方法,回火硬度法研究了一种Nb-V-Ti微合金高强管线钢加热温度与奥氏体组织,合金元素溶解及析出的关系,并对不同温度加热后奥氏体的动态再结晶行为及其组织进行了研究。试验结果表明,随加热温度的升高,奥氏体晶粒尺寸逐渐增大,在1 200℃以上易出现粗大晶粒,加热温度过高形成的粗大奥氏体晶粒延缓了再结晶行为,容易造成混晶现象。

Through heating process simulation, the relationship between heating temperature and austenite microstructure, solution and precipitation of alloying elements had been studied, by using the method of microstructure observation and quenching and tempering experiments, at the same time, the recrystallization of deformed austenite at different heating temperatures has been studied by single hit compression test on the Gleeble 2000. The resuits show that austenite grain grows with increasing heating temperature and grain coarsening was found when temperature exceeded 1 200 ℃. The grain coarsening retards the austenite recrystallization and produces mixgrains, so the optimizing heating temperature of the microalloyed steel in TCMP has been discussed.