60kg/m重轨轧制全道次的有限元模拟和试验研究

Finite element simulation and experimental research of metal flow during the whole rolling process of 60 kg/m heavy rail

对60kg/m U71Mn重轨轧制全道次进行了三维热力耦合有限元模拟。轧辊建模时分别通过翻转和平移轧辊来实现轧件翻钢和侧向推钢过程;轧件的建模采用抽取中间截面网格拉伸的建模方法,既消除网格畸变的影响又使得前后数据得到继承。模拟结果表明:重轨轧制过程中存在严重的不均匀变形,铸坯横断面金属质点在轧制过程中沿轧制方向不同步;轨底部位金属沿轧制方向和轨底高度方向流动;轨腰部位金属沿轧制方向和宽度方向流动,其中心向轨底部位偏移;轨头金属沿轧制方向被延伸。人工打孔制造缺陷坯轧制试验的特征点位置变化与模拟结果吻合良好,验证了轧件在各道次的金属流变规律。所建立的金属在轧制过程中的位置对应关系可以为生产过程中轧制缺陷的溯源分析提供便利。

A coupled thermo-mechanical finite element simulation was carried on whole rolling passes of the 60kg/m heavy rail. The tilting and pushing passes were achieved by turning over and moving the rollers respectively. The model of the workpiece was established by extracting the middle cross-section grid and stretching it, which elimi- nated the influence of mesh distortion and also made the data before and after inherited. The results show that： the deformation during the rolling process of heavy rail was extremely non-uniform and the metal particles in the slab cross-section are out-of-step along the rolling direction; the metal in rail base flows along the rolling direction and height direction; the metal flows along the rolling direction and width direction in rail web and its center shifts to the rail base; the metal at the rail head extends along the rolling direction. The results obtained by rolling experi- ment of billet with made hole defects are in good agreement with the simulated results. Thus, the law of metal flow is obtained and verified. The correspondence is established of the metal position during the rolling passes can make it convenient to find and analyze the rolling defects in the production process.