Papers by Author: Yu Can Fu

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Authors: Gao Qun Liu, Zheng Cai Zhao, Yu Can Fu, Zhi Liang Yan
Abstract: This article studies the forces and tool wear behavior in the milling process of Ni3Al-base superalloys with cemented carbide cutting tools. The effects of cutting parameters on the machinability of these superalloys are experimentally discussed. The results indicate that the forces increase with the increase of the axial depth of cut, the radial depth of cut and the feedrate per tooth. The cutting tools wear rapidly in the milling process of Ni/Al superalloys. The cemented carbide cutting tool with TX coating is more suitable for machining Ni/Al superalloys when compared with the tool with TiCN coating.
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Authors: Wen Feng Ding, Jiu Hua Xu, J.B. Lu, Yu Can Fu, Bing Xiao, Hong Jun Xu
Abstract: In this paper, the disadvantages of the current CBN (Cubic Boron Nitride) grinding wheels were firstly introduced briefly, for indicating that it was very urgent and important to develop new kinds of grinding wheels with excellent performance to replace the conventional wheels. Then high temperature brazing experiments of monolayer CBN wheels with Ag-Cu-Ti filler alloy were carried out. The result shows that the filler alloy has good wetting capability towards CBN grits. The results of scanning electron microscope (SEM) and energy dispersion spectrometer (EDS), as well X-ray diffraction (XRD) analysis show that, just because during brazing titanium atoms in filler alloys segregated preferentially to the surface of the CBN to form Ti-nitride or Ti-boride layer by reaction between titanium atoms and nitride and boron atoms at elevated temperature, strong chemical joining was formed in the interface between CBN grits and filler alloys. Finally, the contrastive grinding experiments were performed between the monolayer brazed CBN grinding wheels and the electroplated ones. The results show that the brazed wheels have more excellent performance than the latter.
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Authors: Wen Feng Ding, Jiu Hua Xu, Z.Z. Chen, Hong Hua Su, Yu Can Fu, Y. Chen
Abstract: Brazing experiments of polycrystalline CBN abrasive grains and AISI 1045 steel matrix using 95(72Ag-28Cu)-5Ti (wt.%) filler alloy were carried out at the heating temperature of 900 °C for the dwell time of 8 min. The microstructure of the brazing interface among PCBN grain, Ag-Cu-Ti alloy and steel matrix, was characterized with optical microscope, scanning electron microscope and X-ray diffraction equipment. Grinding performance of the brazed polycrystalline CBN abrasive tools was evaluated experimentally by comparison with monocrystalline CBN counterparts. The results show that the reaction layer between polycrystalline CBN abrasive grain and Ag-Cu-Ti filler layer consists of the compounds of Ti-nitride, Ti-borides and Ti3AlN. The resultants have played an important role in terms of strong chemical joining at the grain-filler interface. The brazed abrasive tools with polycrystalline CBN grains have given higher material removal rate and longer service life than that with monocrystalline CBN ones.
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Authors: Zheng Cai Zhao, Jiu Hua Xu, Yu Can Fu, Zhi Wei Zhang
Abstract: This article studies the performance of ceramic grinding wheel made of micro-crystalline alumina in the creep feed grinding of nickel-based superalloy Inconel 718. The effects of abrasives and specific pore volume on the performance of wheels are experimentally discussed. Grinding force and temperature were measured and analyzed during grinding tests. The surface roughness was used to describe the quality of ground surfaces. The results indicate that the micro-crystalline alumina SG abrasive wheel with large specific volume has good grinding properties when grinding Inconel 718 in comparison of the wheels with PA abrasives or SG abrasives of small specific pore volume.
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Authors: Ying Fei Ge, Jiu Hua Xu, Yu Can Fu
Abstract: High speed milling tests were performed on the SiCp/2009Al composites to investigate the cutting forces by using PCD tools in the speed range of 600-1200m/min. The results showed that the peak value of the cutting force Fy (in the tool radial direction) was in the range of 700-1450N under the present cutting condition. The maximum amplitude of cutting force vibration in the tool radial direction can reach 700N. Cutting forces increased with increasing feed rate or radial depth of cut and decreased with increasing cutting speed. Negative rake angle and relatively large tool nose radius were recommended as far as cutting forces was concerned. Materials with higher volume fraction or smaller reinforcement particle size had the bigger cutting forces. T6 heat treatment can increase the cutting forces significantly but the using of coolant can decrease the cutting forces evidently.
871
Authors: Guo Sheng Geng, Jiu Hua Xu, Yu Can Fu, Y.F. Ge, C. Su
Abstract: Cutting temperature has direct effects on tool wear and tool life, as well as machining accuracy and machining quality. Titanium alloys, however, are generally machined at lower cutting speeds with cemented carbide tools due to its low thermal conductivity and high chemical reactivity with cutting tool materials. This paper deals with cutting temperature in high-speed milling of a near alpha titanium alloy. The measuring principle of cutting temperature by the workpiece-constantan thermocouple method was illustrated and the physical meaning of the electromotive force (EMF) signals was described in the paper. The effects of cutting parameters and wear status on cutting temperature were studied, and the temperature distribution along the cutting edge was investigated.
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Authors: Ying Fei Ge, Jiu Hua Xu, Yu Can Fu
Abstract: High-speed milling tests were performed on SiCp/2009Al composites in the speed range of 600-1200m/min using PCD tools to investigate the cutting temperatures and the influence factors. The results showed that the cutting temperature could reach 580°C under the given cutting conditions. Graphitization took place on the PCD tools under the high cutting temperature coupled with the effects of abrasive wear of SiC particles and catalysis of copper in the 2009 aluminum matrix. Cutting parameters, tool materials, workpiece materials and tool wear condition had significant effect on the high speed milling temperature while tool geometries had the minor effect. Among these influence factors, cutting speed was the most significant factor. Reinforcement volume fraction was the less significant factor and followed by radial depth of cut, feed rate and tool materials.
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Authors: Bei Zhang, Hong Jun Xu, Yu Can Fu, Hong Hua Su
Abstract: This study has developed a new kind of high performance monolayer brazed diamond tool for ceramic grinding. The grit size of the diamond brazed in the grinding wheel surface is 300m, which has never been reported in diamond tools for ceramic precision machining. The experiment has achieved wonderful surface finish of Zirconia workpiece. This does owe to the designed and precision conditioned topography of the new developed grinding wheel. The topography of the grinding wheel before and after dressing has been measured by means of laser triangulation method. Then the Zirconia workpiece has been ground. The obtained Ra value decreases with no spark grinding times and the minimum Ra of the ground surface is 0.11m. The study proved that the brazed large grit diamond tools would realize high efficiency and precision grinding, namely, high performance of ceramic grinding.
388
Authors: Hong Hua Su, Yu Can Fu, Jiu Hua Xu, Wen Feng Ding, Hong Jun Xu
Abstract: The monolayer brazed diamond tools have recently been used increasingly in hard-brittle materials grinding because of their excellent grinding performances as long tool life, high material removal rate and large inter-grit chip space, etc. However, they possess an inherent shortcoming of the high roughness of the grinding surface. This work is an attempt to reduce the over-protruded grits of the monolayer brazed diamond wheel so that precision grinding operations can be executed effectively. In this investigation, the monolayer brazed diamond wheels with regular distribution pattern of grit have been dressed by a special conditioning process and used in precision grinding experiments on Li-Ti ferrite. The outcome of this attempt appeared highly encouraging. A substantial improvement of the ground surface roughness could be achieved with the dressed monolayer brazed diamond wheels.
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Authors: Bo Ping, Yu Can Fu, Zhi Wei Zhang, Zheng Cai Zhao
Abstract: An investigation is reported of the effect of grinding speed on energy partition for grinding of Inconel 718 with virtrified CBN wheels. Temperature was measured in the ground surface of Inconel 718 with semi-natural thermalcouple. The energy partition and heat flux distribution within the grinding zone were estimated and analyzed. The result indicates that low energy partitions were found to be convected into the workpiece and wheel, both were lower than 10%, and the energy partition into the coolant decreases greatly from 75% to 25% while the one into the grinding chips increases from 15% to 70% with the increasing speed.
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