钛含量对热轧带钢奥氏体晶粒长大与析出特性的影响

Effect of Titanium Content on Austenite Grain Growth and Precipitated Behavior of Hot-Rolled Strips

采用金相法、相分析、X射线衍射技术,定量研究了不同钛含量的微合金高强钢加热温度及保温时间对奥氏体晶粒长大尺寸的影响,以及其析出特性对力学性能的影响.结果发现,当加热温度达1000～1150℃时,在保温时间相同时,B钢奥氏体晶粒尺寸小；但当温度升高到1150℃以上时,B钢奥氏体晶粒尺寸快速增大,粗大的含钛颗粒对奥氏体晶粒长大几乎无阻碍作用.随钢中钛含量增加,A、B钢中的MC析出相的量分别占M3C相析出总量的7.5％、159.0％（质量分数,下同）.MC与M3C的质量比增大,则其对应钢的强度值也增大.A、B钢中10 nm以下的析出相质量分数分别为2.2％、21.7％.

The influence of heating temperature and holding time of different Ti content of microalloy high strength steel on austenite grain size and the influence of the precipitation characteristics on mechanical properties were quantificationally investigated through the methods of metallography, phase analysis and X-ray diffraction. The re- sults show that, under the heating temperature of 1000-1150℃ and the same soaking time, the steel 13 has small size of austenite grain. However when the temperature rises to 1 150 ℃ and above, austenite grain size in steel B increases fast, bulky containing Ti precipitates almost have no side effect on austenitic grain growth. With Ti con- tent in steel increasing, MC precipitated phase in steel A and B respectively is 7.5%, 159.0% of the total M3C precipitated phase. When the ratio of MC/M3C increases, the corresponding strength of steel also increases. The mass fraction of less than 10nm precipitation phase in steel A and B is 2.2% and 21.7%.