关键词: 振动, 双辊铸轧, 铸态组织, 晶粒细化, Kiss点

Abstract: A set of 160mm×150mm vibration casting machines were designed and manufactured in order to carry out the research on the product quality of twin roll strip casting processes.The effects of vibrations on the crystal nucleation and cast microstructure were studied.The distributions and growth rules of the cast microstructures in the solidification zones under the conditions of vibration and non-vibration were compared and analyzed. It is pointed out that improving the vibration frequencies may effectively promote the grain refinement. At the same time, according to the requirements of industrial experiments, a three-dimensional flow field-temperature field coupling finite element simulation model of molten pools was established by using CFD software.The results show that increasing the vibration frequencies and amplitudes may enhance the “mixing” effects of the cast rolling molten pools, which may promote the grain refinements and restrain the segregations. It is found that the solidification point positions(i.e. Kiss point height) are not distributed along the width direction of the plates in the castrolling processes. As a result, the longitudinal inhomogeneous extensions are the direct factors to induce the cast rolling oblique cracks. And the Kiss point position will be moved up with the increase of the amplitudes and the frequencies.

Key words: vibration, twin-roll casting, cast microstructure, grain refinement, Kiss point