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Tribology at high temperature: experimental and numerical analysis of interfacial behavior taking into account the influence of thermomechanical contact conditions

Abstract : In hot-working of steel components, friction conditions at the tool/workpiece interfaceare severe due to the relatively high temperatures (850°C-1250℃) and loads involved in theseoperations. Under these processing conditions, the tool/workpiece interface usually involvesthe presence of an oxide layer and a lubricant film. The objective of this research is to analyzethe tribological effect of the oxide layer and its interaction with the lubricant used. As part ofthe joint SWITLab laboratory bringing together the industrial group MG Valdunes, theLAMcube of Lille and the LAMIH UMR CNRS 8201, the hot forging process of a railwaywheel for high-speed trains was chosen for the analysis.The rheological effect of the oxide layer and lubricant film on the steel were previouslyanalyzed by means of hot compression tests with standard cylinders and cylinders with aRastegaev design. Additionally, axisymmetric compression and tensile tests were carried out inorder to characterize the mechanical behavior of the tool material at relatively low temperatures.An original multi-scale analysis of the billet/tool contact conditions at high temperaturewas then developed. At macro-scale, the main contact parameters were extracted by means ofthe industrial forging process observations and its FE modeling. Then, upsetting-sliding testsas well as roll-on-disc tests were conducted based on the macro-scale contact conditions. Afterthe upsetting sliding both crushed and embedded oxides were found to be present on the crosssection of the tested samples. At the micro-scale level, the stick-slip phenomenon occurs due toaccumulation of the crushed oxides, which transform the interfacial contact conditions from alubricant/oxide configuration to an oxide/oxide condition.Finally, a FE model of the railway wheel hot forging process, taking into account thethermal characteristics of the oxide layer, the coefficient of friction determined at meso-scaleand the behavior of the tool material, has been developed. This model can correctly predict theforging forces and the filling of tools.
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Submitted on : Monday, October 18, 2021 - 5:46:26 PM
Last modification on : Tuesday, November 23, 2021 - 9:45:06 AM

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  • HAL Id : tel-03384134, version 1

Citation

Ivan Serebriakov. Tribology at high temperature: experimental and numerical analysis of interfacial behavior taking into account the influence of thermomechanical contact conditions. Engineering Sciences [physics]. Université Polytechnique Hauts-de-France; Institut national des sciences appliquées Hauts-de-France, 2021. English. ⟨NNT : 2021UPHF0009⟩. ⟨tel-03384134⟩

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