异型连铸坯结晶器内表面纵裂萌生区域

 针对异型坯连铸过程中出现较多表面纵裂的问题，使用有限元软件ABAQUS建立铸坯二维微段模型，使用Fortran语言编写表面热流子程序DFLUX模拟铸坯在结晶器内的凝固传热过程，使用接触算法与重启动技术分析铸坯在热应力、表面摩擦力及钢水静压力下坯壳的受力状态。结合材料力学属性分析得出，R]角、腹板中心、翼缘中心与窄面中心位置为异型坯表面纵裂纹最易萌生区域，其中R]角处距离弯月面约200 mm处更容易萌生表面纵裂纹，腹板、翼缘中心与窄面中心距离弯月面180 mm处更容易萌生表面纵裂纹。

Initiation locations of longitudinal surface cracks on beam blank in mold of continuous casting

During beam blank continuous casting production,lots of longitudinal cracks easily appear on the surface. In order to study the initiation locations of longitudinal surface cracks in the mold,a coupled thermo-elasto-plastic finite ele-ment model was established to compute the temperature and stress using the software ABAQUS. The user subroutine DFLUX was applied to simulate the heat transfer and solidification field. The stress-strain field under the influence of thermal stress,the surface friction and the ferrostatic pressure were analyzed by the method of contact algorithm and the restart scheme. According to the results,it can be inferred that the forming locations of longitudinal surface cracks easily appear on the surface,such as the fillet,the web center,the flange tip and the flange center. Moreover,initiation loca-tions forming longitudinal surface cracks should be:position at the fillet at a distance of 200 mm to the meniscus,and the other three sections at a distance of 180 mm to the meniscus.