百米U75V钢轨矫直前冷却过程温度场的有限元分析

通过研究U75V钢轨冷却过程的热边界条件,采用三维瞬态非线性有限元法计算了百米钢轨矫直前845～150℃冷却过程的温度场。结果表明,在冷却过程中的钢轨横截面不同位置的温度下降速率不同,在冷却初期(200～2 000s),每条冷却温度线都出现一个温度降低缓和的"平台"阶段,如轨底边部冷却速度最快,开始相变时间最早;在冷却2 500～3 000s时,轨头、轨腰、轨底中心的温度迅速下降,轨头与轨底边部的温差约5℃,在冷却5 000～7 000s时,各部位温差趋于一致;计算温度值和现场实测值差别小于50℃。

Finite Element Analysis on 100-Meter Rail Temperature Field of U75V Steel during Cooling before Straightening

With analyzing the thermal boundan conditions in cooling process of U75 V steel rail, the temperature field of 100 in steel rail during cooling process at 845 ~ 150 ℃ before straightening has been calculated by using three-dimensional non-linear finite element method. Results showed that during cooling process the temperature decrease rate was different at different position of cross- section of rail, in initial cooling period (200 ~2 000 s) a "platform' period with temperature decreasing slow for each curve occurred, for instance the cooling rate was fastest at edge of rail bottom at which the phase transition was earliest: in cooling for 2 500 ~ 3 000 s, the temperature at rail head, rail waist and median of rail bottom decreased very quickly and the temperature difference between rail head and edge of rail bottom was about 5℃ , in cooling for 5 000 ~ 7 000 s the temperature of each position tended to show no difference; the difference between calculated temperature and measured temperature at situ was less than 50℃.