U75V钢轨钢晶粒长大模型及其在焊接中的应用

钢轨闪光焊焊接接头晶粒尺寸影响着焊接接头的耐磨性能等力学性能。为此,对高速、重载无缝铁路中大量应用的U75V钢轨进行等温淬火试验,测量其在800~1100℃范围内的不同加热温度和保温时间下的平均晶粒尺寸。结果表明:当温度在800~950℃时,晶粒长大速度较小,平均长大速度约为0.4μm/min;温度在950~1100℃时晶粒长大速度加快,平均长大速度约为1.6μm/min。在此基础上建立了U75V钢轨钢在等温条件下晶粒长大的数学模型。利用有限元分析软件Abaqus建立了钢轨闪光焊模型,分析不同温度场对接头晶粒尺寸的影响,并通过实验验证了模拟的正确性。

Grain growth model of U75V rail steel and its application in welding

The grain size of rail flash-butt welding joints affects the wear resistance and mechanical properties of the welded joints. Therefore,for U75V rails used in high-speed and heavy-duty seamless railways,the average grain size in the temperature of 800~1 100 ℃ and different holding times is measured by an austempering test. The results show that when the temperature is 800~950 ℃,the growth rate of the grains is slow,the average growth rate is about 0.4 μm/min,and the growth speed of the grains accelerates at the temperature of 950~1 100 ℃,and the average growth rate increases and is approximately 1.6 μm/min. A mathematical model of the grain growth of U75V rail steel under isothermal conditions is established. In addition,the finite element analysis software Abaqus is used to establish the rail flash-butt welding model and the influence of different temperature fields on the grain size of the joint is analyzed,and the simulation results are verified by experiments.