中厚板边部折叠模拟实验及机理研究

通过对中厚板边部折叠试样的检测分析,对其产生机理和影响因素进行研究. 结果显示,中厚板边部折叠现象是板材横轧宽展过程中侧面材料在轧制中受轧辊作用而翻转到板材表面的结果. 折叠缺陷处所观察到的微观组织结构,是轧制前板材表面在高温下形成的氧化铁及脱碳层形成的. 建立了轧制有限元数值模型,证实折叠缺陷是在轧制过程中由侧面的折叠翻转所造成的. 通过实验室实验,得到铸坯边部质量、轧制制度、宽展道次及轧制压下量对中厚板折叠缺陷的影响. 实验结果表明横轧宽展导致折叠缺陷的出现,铸坯边部质量对其没有影响,轧制过程中铸坯侧边的折叠经翻平形成表面折叠缺陷,随着横轧展宽的道次及压下量增加,折叠缺陷距边部距离变大.

Simulation experiments and mechanism of medium plate edge folding

The formation mechanism and influencing factors of fold defects at the medium plate edge were studied by detecting and analyzing edge folding samples. It is found that the plate edge folding phenomenon results from the transformation of slab lateral side to plate surface during the broadside rolling process. The microstructure observed at the fold defects is composed of iron oxide and a de-carburization layer formed at high temperature in the plate surface before rolling. Finite element numerical simulation of the rolling process confirms that the folding defects are mainly caused by the transformation of lateral side. The influences of slab defects, rolling procedures, broadening passes and reduction on the plate fold defects were obtained by rolling experiments. Experimental results show that rolling spread leads to the fold edge defects, which do not depend on the quality of the slab. In the process of rolling, the folding of lateral side transfers to the plate surface and changes to be edge seam defects. The distance of folding to the edge increases with the increment of broadside rolling passes and reduction.