Papers by Keyword: Built-Up Layer

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Authors: Daniel García-Jurado, José Manuel Mainé, Moisés Batista, Juan Manuel Vázquez-Martínez, Francisco Javier Puerta, Marinao Marcos
Abstract: The combination of specific properties, cost, reliability and predictable behavior, guarantee that the aluminium alloys will be kept as one of the materials used in aerospace industry. When aluminium alloys are machined, transfer of cutting material to cutting tool is related with the secondary or indirect adhesion wear mechanism, which can be presented in form of Built-Up Layer (BUL) and Built-Up Edge (BUE), located in two defined zones of the tool, cutting edge and rake face respectively. The material adhered involve tool properties, geometrical and physicochemical alterations which modify the initial cutting conditions, in accordance with currently concept of tool wear. Until now, a generalized lack is observed in methodologies to assessment the secondary adhesion wear in machining of aluminium alloys, mainly due to the difficulty found in characterizing and quantify thereof. In this paper, based in Focus-Variation Microscopy (FVM) techniques, a methodology is proposed through high-resolution optical 3D topography measurements obtained from WC-Co worn tools tested in the dry turning of UNS A92024-T3 alloy, in order to obtained information about effects and intensity of secondary adhesion wear.
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Authors: J.M. Sánchez, M.A. Sebastián, J.M. González, M.S. Carrilero, Mariano Marcos Bárcena
Abstract: Tool adhesion wear can be produced by two different ways. On the one hand, direct adhesion wear is caused by the incorporation of tool particles to the chips. On the other hand, indirect adhesion wear is caused by the incorporation of fragment of the workpiece material to the tool. When these fragments are removed, they can drag out tool particles causing tool wear. Indirect adhesion can be localised in the tool edge, giving rise to Built-Up Edge (BUE), or in the tool rake face, giving rise to Built-Up Layer (BUL). In this work microstructural differences between both effects in different machining processes of Al-Cu alloys have been analysed. From these microstructural differences, a model has been proposed for the mechanism of formation of both effects.
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Authors: Xiao Qi Song, Yukio Takahashi, Wei Ming He, Tohru Ihara
Abstract: Built-up Layer (BUL)/Built-up Edge (BUE) formed on the tool surface can be treated as a protective, thermal barrier or lubricant films especially in the extreme severe conditions when machining the metal materials, which can sustain the tool effective and wear resistance. In order to have a thorough understanding of the adhesion effect during machining, experiments have been carried out to investigate the performance and the formation mechanisms of adhering layer on the carbide tool in machining of aluminium alloys A6063, carbon steel S45C and difficult-to-cut hardened steel S45C (H-S45C). The morphology of tool adhered surface was examined by employing Scanning Electron Microscopy (SEM), the dimensions of adhering layer were measured by Laser Scanning Microscopy (LSM) and the elements on the tool were analyzed by Electron Probe Micro Analyser (EPMA), respectively. The atomic-scale cluster adhesive friction model is proposed to explain the tool-chip contact conditions, which considers the nature of the shear strain, shear strain rate and temperature distribution in the secondary deformation zone. The model is a dynamic model and the rate equation approach can be applied to estimate the formation process of adhering layer during machining. Results have shown that the adhering layer will give rise to BUL on the tool rake face and the BUE on the cutting edge and clearance face.
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