贝氏体钢轨热轧过程中再结晶行为及组织控制

摘要

Recrystallization behavior of KB1250 bainitic steel rail during hot deformation under different conditions was investigated by a Gleeble-1500D thermal simulation machine.The effect of deformation process parameters on recrystallization behavior of the rail was analyzed.The results show that for the KB1250 bainitic steel rail,the dynamic recrystallization will occur during hot-rolling at 1 100 ℃,whereas a small amount of dynamic recovery occurs only during hot-rolling at from 900 to 1050 ℃,and that the static recrystallization fraction,i.e.softening rate,is as great as approximately 1 .0 during deforming at 1000 ℃or 1050 ℃.In addition,when being multipass compressed,lower deformation temperature is beneficial to grain refinement,but the compression at higher temperatures will be easy to form mixed crystal for the KB1250 bainitic steel rail.%采用Gleeble-1500D热模拟试验机研究了KB1250贝氏体钢轨在不同条件下热变形时的再结晶行为。分析了变形工艺参数对该钢轨再结晶行为的影响。结果表明，KB1250贝氏体钢轨在1100℃热轧时发生动态再结晶，而在900～1050℃热轧仅发生少量的动态回复；在1000℃、1050℃变形时，静态再结晶分数即软化率几乎达到1．0。KB1250贝氏体钢轨被多道次压缩时，变形温度低有利于晶粒细化，而变形温度高则容易发生混晶。