Analytical Model to Predict the Free Surface Profile of Outgoing Material in Oval-to-round Pass Rolling when Cross-section of Incoming Material is not Circular and Roll Gap Changes

초록

There is a strong demand for the development of an analytical model that is necessary to quickly perform the roll pass design of hot rod (or bar) rolling process. In line with this, this study proposes an analytical model that predicts the free surface profile (FSP) of outgoing material in oval-to-round pass rolling sequence even when the cross- section of incoming material is not circular and roll gap changes. The separation angle and point were calculated by interpolating the intersection angle and the groove angle. FSP passing through the maximum spread of outgoing material and the separation point is calculated based on a weighting function depending on the geometry of incoming cross- section and roll groove. The performance of the proposed model was verified by finite element analysis that simulated 10-pass continuous bar rolling process. FSPs predicted by the analytical model and those by FE simulation were in good agreement. In addition, the proposed analytical model was applied to other 4-pass continuous rolling. It has been shown that it is possible to quickly calculate the amount of roll gap adjustment in each pass that improves the roundness of the material (from 83.57 to 98.65) in the final pass without the time-consuming FE analysis.

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