An approach to estimate the mean friction coefficient of metal in high temperature rolling

초록

This paper proposes a method to estimate the mean friction coefficient of material (AISI 4135) rolled at high temperature (900 ~ 1200°C). The fundamental idea considered in this method is that the mean friction coefficient of material in hot rolling can be estimated by minimizing the difference between the spreading and roll force measured from a pilot hot rolling test and those computed by finite element analysis. A pilot hot rolling test was conducted at temperatures ranging from 900 to 1200°C and reduction ratios of 20 to 40%. A series of three-dimensional FE analysis of the hot rolling test was performed by changing the friction coefficient from 0.2 to 0.5 at intervals of 0.01. Results reveal that the mean friction coefficient increases as the material temperature and reduction ratio increase. The effect of reduction ratio variation on the friction coefficient is greater at lower temperature (900°C) than that at higher temperature (1200°C). The method proposed in this study was found to be useful to estimate the mean friction coefficient of material in hot rolling since elaborative techniques are necessary to install the expensive sensors (pins and force transducers) inside the roll and align them correctly. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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