Xiaotao Liu

Numerical Analysis of Roll Deflection for Sendzimir Mill

The present work introduces a new type of numerical analyzing method: the contact element method with two relative coordinates (CEM). The main characteristic of the procedure is elements meshing on the basis of the contact length between objects and that each element has two relative coordinates. The ordinary expression of this procedure is D X [C XY (i)]=D Y [C YX (i)]. Through this method, the CEM function of the 20-high Sendzimir mill and the deflection function expression of every roll are obtained. A computational software SM4SM for the Sendzimir mill has been developed, by which the deflection condition of rolls S, O, I, and A can be obviously seen. The results obtained by CEM have also been compared to that by the finite element method.

An insight into the deformation and orientation development of severely plastic deformed aluminum

Severe plastic deformation (SPD) techniques have attracted significant attention in the last two decades due to its capacity of producing bulk ultra-fine grained (UFG) or nanostructured materials, by imposing very high plastic strain. Equal channel angular pressing (ECAP), or equal channel angular extrusion (ECAE), is one of the most widely used SPD techniques. During ECAP, a sample is pressed through a die which consists of two channels with equal cross-section intersecting at an angle varying from 60° to 150°. Since the cross-section geometry of the sample remains nearly unchanged, the materials can be deformed to a very high strain by repeating the process. The deformation mechanism of ECAP is very complicated and it is dependent on the die geometry and material properties. It has been assumed as simple shear on the intersecting plane of two channels at ideal conditions, such as frictionless, perfectly plastic material and very sharp outer corner. However, from the view of texture evolutions, many expe...