Central voids or voids at the middle layer are often found in thin strips produced by twin-roll casting. These strips are in general so thin that they are unable to take a required reduction in thickness to close the voids. In the present investigation, equal-speed rolling and differential-speed rolling were compared to assess the effect of differential speed on closure of the voids by the rigid-plastic finite-element analysis. As a result, shear deformation developed in differential-speed rolling was found to reduce the reduction in thickness required for void closure. An increase in speed ratio, length of deformation zone, or friction coefficient at the interface expedited the progress in void closure. However, as the speed ratio exceeded thickness ratio, a portion of rolling power was dissipated extensively by excessive slip at the interface. Moreover, tensile stress developed which would cause cracks in the strip. (C) The Minerals, Metals & Materials Society and ASM International 2015
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机译:在双辊铸造生产的薄带中经常发现中央空隙或中间层的空隙。这些条通常太薄,以致于它们无法减小厚度以封闭空隙。在本研究中,比较了等速轧制和差速轧制,以通过硬塑性有限元分析评估差速对空隙封闭的影响。结果,发现在差速轧制中产生的剪切变形减小了空隙封闭所需的厚度减小。速度比,变形区长度或界面处的摩擦系数的增加加快了空隙封闭的进程。但是,当速度比超过厚度比时,由于界面处的过度滑动,一部分轧制力被大量耗散。而且,产生了拉应力,该拉应力将导致带材中的裂纹。 (C)矿物,金属和材料学会和ASM International 2015
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