Letteratura scientifica selezionata sul tema "Surfaces (Technology) Mechanical wear. Metal-cutting"
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Articoli di riviste sul tema "Surfaces (Technology) Mechanical wear. Metal-cutting"
1
., Nagaraja, Raviraja Adhikari e T. Yasir. "An investigation into tapping of Al6061/SiC metal matrix composite with straight flute HSS machine tap". Journal of Mechanical Engineering and Sciences 13, n. 1 (29 marzo 2019): 4575–95. http://dx.doi.org/10.15282/jmes.13.1.2019.16.0386.
Testo completoAbstract (sommario):
The present study deals with tapping of Al6061/SiC metal matrix composite. Stir casting technique was used for the fabrication of composite. Castings were produced by varying weight percentages of SiC (5%, 7.5% and 10%) of 23μm size in Al6061. The tapping experiments were conducted for the machinability study of Al6061/SiC metal matrix composite using M8 x 1.25 HSS machine taps. The tapping operation was performed under dry condition with different cutting speeds. Torque required for tapping was measured using piezoelectric based 4-component drill tool dynamometer. Surface morphology and profile of thread surfaces were analysed using Scanning Electron Microscope (SEM) and metallurgical microscope. Estimation of progressive flank wear of machine taps was undertaken using profile projector. The performance of HSS machine tap was evaluated in terms of tapping torque, tool flank wear, and surface characteristics of thread surfaces. The flank wear of uncoated HSS machine tap increased with the increase in weight percentage of SiC in Al/SiC composite for a particular cutting speed. Further, when the matrix materials were reinforced by the same kind and the same weight percentage of SiC particles, the flank wear of the tool was found to increase with cutting speed. In addition, the damage caused to thread profiles increased with the increase in cutting speed and weight percentage of SiC.
2
Pang, Minghua, Xiaojun Liu e Kun Liu. "Effect of conical micro-grooved texture on tool–chip friction property and cutting performance of WC-TiC/Co cemented carbide tools". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 233, n. 5 (4 ottobre 2018): 791–804. http://dx.doi.org/10.1177/1350650118804907.
Testo completoAbstract (sommario):
Purpose This study aimed to clarify the influence mechanism of conical micro-grooved texture on the tool–chip friction property and cutting performance of WC-TiC/Co cemented carbide tools under flood lubrication conditions. Design/methodology/approach Conical micro-grooved texture was fabricated on the tool rake face using laser texture technology. Metal cutting tests were conducted on AISI 1045 steel with conventional and developed tools for various cutting speeds (80 m/min to 160 m/min) and conical angles of micro-grooved texture (2 ° to 5 °) under flood lubrication condition. The effect of conical micro-grooved texture on the tool cutting force, tool–chip friction coefficient, surface roughness of the machined workpiece, and wear of the tool rake face was determined. Findings Unlike the conventional tools, the conical micro-grooved tools successfully resulted in reductions in metal cutting force, tool–chip frictional coefficient, surface roughness of the machined workpiece, and wear of the tool rake face. These reductions were more noticeable than those of conventional tools with increases in the cutting speed and conical angle of the micro-grooved texture. Detailed research indicated that conical micro-grooved channel exhibits a directional motion characteristic of liquid, which accelerated the infiltration of cutting fluid at the tool–chip interface. Substantial cutting fluid was supplied and stored at the tool–chip interface for the conical micro-grooved tools. Therefore, the conical micro-grooved texture on the tool rake face showed evident advantages in improving tool–chip friction and tool cutting performance. Originality/value The main contribution of this study is proposing a new conical micro-grooved texture on the tool rake face, which improved tool–chip friction and tool cutting performance.
3
Astarita, Antonello, Silvio Genna, Claudio Leone, Fabrizio Memola Capece Minutolo, Valentino Paradiso e Antonino Squillace. "Laser Cutting of Aluminium Sheets with a Superficial Cold Spray Titanium Coating". Key Engineering Materials 611-612 (maggio 2014): 794–803. http://dx.doi.org/10.4028/www.scientific.net/kem.611-612.794.
Testo completoAbstract (sommario):
In the manufacturing of metal components both wear and corrosion have to be considered. In particular, corrosion is a primary problem in the aeronautic field, where the aluminium alloys are affected by several corrosion typologies. Furthermore, nowadays carbon fibre reinforced plastics (CFRP) are finding an increasing use, but they can induce galvanic corrosion phenomena when coupled with aluminium alloys. To overcome this problem, corrosion resistant coatings are used on aluminium components. On these premises, the realization of a titanium coating on aluminium components could allow the coupling of CFRP and aluminium alloys, improving the corrosion resistance. Cold Spray Deposition is a recent technology to realize these coatings. This technology allows the production of near fully dense coatings on metallic surfaces. In many applications the coated aluminium sheets have to be machined (cut or drilled). Machining with conventional cutting methods leads to both tool wear and damages in the coating. Laser cutting represents a promising alternative: it does not involve any mechanical cutting force or tool wear and, thanks to the small laser beam spot, it allows to realize complex shapes. In this paper, laser cutting of an Al alloy sheet (0.6 mm thick) coated with Ti Alloy, was studied. The adopted laser source was a 150 W, lamp pumped Nd:YAG, specifically developed for micro-machining operations on metals. During the tests, the process parameters (cutting speed, pulse duration and entrance side) were changed and the kerf geometry was analysed as a function of the process parameters.
4
Tian, Xinli, Long Wang, Wanglong Wang, Yongdong Li e Kaiwen Ji. "Tool wear characteristics of cutting and extrusion processing technology based on the edge-chipping effect". Industrial Lubrication and Tribology 68, n. 2 (14 marzo 2016): 191–96. http://dx.doi.org/10.1108/ilt-04-2015-0051.
Testo completoAbstract (sommario):
Purpose – The cutting and extruding processing technology for ceramics based on the edge-chipping effect is a new contact removal machining method for hard, brittle materials such as engineering ceramics. This paper aims to provide an important reference to understand the tool wear mechanism and the wear law of this new processing technology. Design/methodology/approach – The real-time temperature monitoring and the observation of micro-morphology are used to analyse the wear characteristics of the tool face. In addition, the research focuses on the influence of three processing parameters (axial feed rate, thickness of flange and depth of groove) on characteristics including tool wear. Findings – The temperature variation shows that the new processing technology improves the tool temperatures condition. The tool is worn mainly by mechanical friction including abrasive wear, and the flank face also suffers the sustained scratching of residual materials on the rough machining surface. With increased feed rate, the wear of the rear face of the major flank initially decreased and then increased. As the depth of the retained flange increases, the wear became worse. The wear initially decreased and then increased with increasing depth of groove. Research limitations/implications – Study on the new processing technology is still in its early stages. Therefore, researchers are encouraged to test the proposed propositions further. Practical implications – The machining process itself destroys materials, albeit a controllable manner: based on this principle, the authors proposed a new machining technology based on cracks driven by edge chipping. In this way, the surface of such ceramics is removed. Therefore, the research provides a new method for reducing processing costs and promoting the extensive application of engineering ceramic materials. Originality/value – The cutting and extruding processing technology based on cracks driven by edge-chipping effect makes full use of the stress concentration effect caused by prefabricated defects, and the edge-chipping effect which occurs during machining-induced crack propagation. The wear mechanism and law of its tool is unique than other machining ways. This paper provides an important reference to understand the tool wear mechanism and the machining mechanism of this new processing technology. With the application of this study, the ceramics could be removed with less energy consumption and the tools with the hardness of lower than its own one. Therefore, it could not only reduce the processing costs but also promote the extensive applications of engineering ceramic materials.
5
Zhang, Hui, Jian Xin Deng, Gui Yu Li, Xing Ai e Jun Zhao. "Effect of Ambient Temperature on Wear of Cemented Carbide Tool Material". Advanced Materials Research 148-149 (ottobre 2010): 276–79. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.276.
Testo completoAbstract (sommario):
Cemented carbide has relatively good mechanical properties, so it is widely used as cutting tools. In this paper, a sliding wear test at high ambient temperature between cemented carbide tool material and ceramic was carried out using a ball-on-disc wear-test machine. The characteristics as to wear rate and friction coefficient were investigated. The special wear rate increased with an increase in operating temperature. The cemented carbide material with addition of TiC phase gave better wear resistance than cemented tungsten carbides at elevated temperature. SEM technology was adopted to observe the worn surfaces of specimens and wear mechanism were simultaneously discussed.
6
Li, Kuan Ming. "Experimental Study on Minimum Quantity Lubrication in Mechanical Micromachining". Advanced Materials Research 579 (ottobre 2012): 193–200. http://dx.doi.org/10.4028/www.scientific.net/amr.579.193.
Testo completoAbstract (sommario):
Mechanical micromachining is a promising technique for making complex microstructures. It is challenging to apply mechanical micromachining in the industry due to the low strength of micro tools. Therefore, it is not easy to accurately control the product dimension error and to raise the production rate. In this paper, the applications of minimum quantity lubrication (MQL) in micro-milling and micro-grinding are presented. MQL is considered as a green manufacturing technology in metal cutting due to its low impact on the environment and human health. This study compares the tool wear and surface roughness in MQL micromachining to completely dry condition based on experimental investigations. The supply of MQL in vibration-assisted grinding is also studied. It is found that the use of MQL results in longer tool life and better surface roughness in mechanical micromachining.
7
Weiser, Ingo Felix, Andreas Feuerhack e Thomas Bergs. "Investigation of the Micro Hardness at the Cut Surface of Fine Blanked Parts with Variation of Sheet Material and Cutting Temperature". Key Engineering Materials 883 (aprile 2021): 269–76. http://dx.doi.org/10.4028/www.scientific.net/kem.883.269.
Testo completoAbstract (sommario):
Fine blanking is a production technology of high importance especially for the automotive industry. As a procedure of sheet metal separation, it is possible to produce complex parts in a single stroke. As a difference to conventional punching, the cutting surface of fine blanked parts can often be used as a functional surface without further process steps. However, fine blanking as a forming process changes the microstructure of the metal sheet to a higher extend than cutting or machining processes. Due to this, it is of utmost importance to investigate the cause-effect-relations between the fine blanking process parameters and the resulting properties of the fine blanked part. Especially the condition of the cut surface as an important quality criterion has to be investigated. The quality characteristics of the cut surface of fine blanked parts are often subject of investigations. In addition, it would be of importance to investigate how the material properties in the shear zone are changed by the fine blanking process. This on one hand in turn can enable conclusions to be drawn about possible punch wear. If, on the other hand, hardening of the cut surface takes place as a result of fine blanking, then this could have a positive influence on the application properties of fine blanked components. Thus, an experimental fine blanking investigation of the micro hardness of the cutting surface has been made with variation of steel material and cutting temperature. It could be demonstrated that the micro hardness increases in direction towards the burr. This is independent on material and cutting temperature.
8
Umanath, K., S. T. Selvamani, K. Palanikumar e Ram G. Dinesh. "Worn Surface Analysis of Hybrid Metal Matrix Composite". Advanced Materials Research 984-985 (luglio 2014): 546–50. http://dx.doi.org/10.4028/www.scientific.net/amr.984-985.546.
Testo completoAbstract (sommario):
Metal to the metal wear analysis of Aluminium (Al6061grade) alloy, dis-continuously reinforced with ceramic particles of SiC and Al2O3deliver this paper. The Al matrix with 5 to 25% of vol. Fractions of SiC and Al2O3particulate reinforcements were formed in Hybrid Metal Matrix Composite (HMMC) by stirring casting technology. They are finding applications in automotive, aeronautical and sport goods. For the proper use of these composites, its mechanical properties and wear properties are to be evaluated. The dry sliding behavior of these SiC and Al2O3particulates HMMCs and that of Al alloy at atmosphere was analyzed with a pin on disc type wear testing machine. The result indicates that, the scanning electron micrographs of the worn surfaces of the hybrid composites show the worn surface of the composite alloy is rougher than the unreinforced Al6061alloy.
9
BELASHOVA, I. S., L. N. RABINSKI e O. V. TURSHAVINA. "EVALUATION OF HARDENING EFFICIENCY WITH CONVECTIVE HEAT AND MASS TRANSFER MECHANISM DURING LASER SURFACE ALLOYING IN REFLOW MODE". Periódico Tchê Química 16, n. 33 (20 marzo 2019): 498–504. http://dx.doi.org/10.52571/ptq.v16.n33.2019.513_periodico33_pgs_498_504.pdf.
Testo completoAbstract (sommario):
The modern stage of equipment development imposes increased requirements for the performance characteristics of parts. Different components and parts of machines, metal-cutting tools and metal structural elements work in the conditions of high friction, high specific loads, high temperatures, a wide range of speeds and impact of aggressive media, for instance. Therefore, improvement the quality, reliability, economical efficiency and productivity of machines, tools, equipment and other engineering products as well as reduction of their specific material consumption and energy consumption is achieved primarily by the use of materials and progressive strengthening technology that improve the hardening, wear resistance, corrosion resistance and other physical and mechanical properties of machine parts and tool. Therefore, the main objective of the paper was to evaluate the mass-transfer during laser surface alloying in the reflow mode. To evaluate the effectiveness of surface hardening technology, it was proposed to use two new parameters – reduced wear and reduced integrated micro hardness of the modified surface layer. Based on an analysis of the experimental data on the wear of a cutter made of HVG and U10 steel, processed by a laser with smears in the reflow mode, the existence of a correlation between the entered parameters is demonstrate and the regression equation is obtained. The proposed approach to evaluating the effectiveness of surface hardening can be used not only in the special case of laser modification but also for any other technology for creating gradient and functional coatings.
10
Seong, Yeonuk, Donghyeon Lee, Jihye Yeom e Junhong Park. "The Feature Extraction through Wavelet Coefficients of Metal Friction Noise for Adhesive and Abrasive Wear Monitoring". Applied Sciences 11, n. 9 (21 aprile 2021): 3755. http://dx.doi.org/10.3390/app11093755.
Testo completoAbstract (sommario):
Friction between metals is a physical phenomenon that occurs in manufacturing machine tools. This annoying noise implies unnecessary metal contact and deterioration of a mechanical system. In this study, for the monitoring of the friction between two metal surfaces, the acoustic signature was extracted by applying the wavelet transform method to the noise measured from the change in contact force for each state of adhesive and abrasive wear. Experiments were conducted with a constant relative speed between the contacting metal surfaces. For the adhesive wear, the peak signal-to-noise ratio (PSNR) calculated by the wavelet transformation increases with the increasing contact pressure. Opposite trends were observed for the abrasive wear. The proposed index formed a group within a specific range. This ratio exhibited a strong relationship with the wear characteristics and the surface condition. From the proposed index calculated by the wavelet coefficients, the continuous monitoring of the wear influence on the failure of the machine movement operations is achieved by the sound radiation from the contacting surfaces.
Tesi sul tema "Surfaces (Technology) Mechanical wear. Metal-cutting"
1
Yen, Yung-Chang. "Modeling of metal cutting and ball burnishing prediction of tool wear and surface properties /". Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1073065455.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xxviii, 254 p.; also includes graphics. Includes abstract and vita. Advisor: Taylan Altan, Dept. of Industrial and Systems Engineering. Includes bibliographical references (p. 240-248).
2
Aguiar, Herbert César Gonçalves de. "Contribuição ao estudo do torneamento do aço inoxidável superduplex empregando ferramentas de metal duro com revestimentos". [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264548.
Testo completoAbstract (sommario):
Orientador: Amauri HassuiDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-21T02:22:26Z (GMT). No. of bitstreams: 1 Aguiar_HerbertCesarGoncalvesde_M.pdf: 11222250 bytes, checksum: a22406ca3de132e13522314dd3490816 (MD5) Previous issue date: 2012
Resumo: Os aços inoxidáveis superduplex são materiais de estrutura bifásica contendo ferrita e austenita, que garantem ao material boa resistência à corrosão por pitting, resistência mecânica e outras características que tornam o material atrativo para as indústrias: petrolífera, óleo/gás, papel/ celulose e química. As mesmas características que tornam o aço inoxidável superduplex mais resistente dificultam a sua usinagem. Portanto, a definição dos parâmetros de usinagem deve atender ao compromisso de por um lado garantir alta produtividade e por outro não comprometer as características do material na sua aplicação. O presente trabalho consiste no torneamento com lubrificação do aço inoxidável superduplex, variando os parâmetros de usinagem e utilizando ferramentas de metal duro da classe M05-M20 revestidas com TiN/Al2O3/TiCN, Al2O3/TiCN e TiAlN, com o objetivo de investigar os efeitos dos parâmetros de usinagem sobre o mecanismo de desgaste da ferramenta através de micrografias obtidas por microscopia eletrônica de varredura (MEV) e de micro-análise semi-quantitativa através do sistema de espectroscopia de energia dispersiva (EDS), a tensão residual induzida no material usinado medida por difração raio-X e a rugosidade na peça. As análises do desgaste da ferramenta mostraram a predominância do mecanismo de adesão/attrition com surgimento de entalhe causado pelo martelamento da rebarba gerada no cavaco durante o torneamento. Isso por sua vez contribuiu ainda mais com a adesão dificultando a remoção do material que aumentou os esforços de corte gerando tensões residuais superficiais compressivas. A ferramenta revestida com TiN/Al2O3/TiCN se destacou por apresentar melhor resultado em termos de vida da ferramenta e menores tensões residuais superficiais de tração no início de vida da ferramenta em relação às ferramentas revestidas com TiAlN e Al2O3/TiCN. A condição de vc = 80 m/min e f = 0,4 mm/rev se destacou dentre todas as classes testadas em termos de produtividade. No entanto, o f = 0,4 mm/rev é prejudicial à integridade superficial gerando tensões trativas e maiores rugosidades
Abstract: The super duplex stainless steels are materials of biphasic structure containing ferrite and austenite, which guarantee a good pitting corrosion resistance, mechanical resistance and other characteristics that make the material attractive to industries: petroleum, oil/gas, paper/cellulose and chemical. The same characteristics that make the super duplex stainless steel more resistant make its machining more difficult. Therefore, the definition of machining parameters should comply with the commitment on the one hand of guaranteeing high productivity and on the other of not compromising the characteristics of the material in its application. This work consists on the turning with lubrication of the super duplex stainless steel, varying the machining parameters and using carbide tools of the grade M05-M20 coated with TiN/Al2O3/TiCN, TiAlN and Al2O3/TiCN, with the objective of investigating the effects of the machining parameters over the tools wear mechanism was also analyzed through micrographs obtained by scanning electron microscopy (SEM) and by semi-quantitative micro-analysis through the system energy dispersive spectroscopy (EDS), the residual stress induced into machined material measured by X-ray diffraction and the parts roughness. The tool wear analysis showed a predominance of the adherence/attrition mechanism with the appearance of grooves caused by the hammering of the burr generated in the chip during the turning. This, in its turn, contributed even more with the adhesion, making it difficult to remove the material which increased the effort in cutting, generating superficial compressive residual stress. The tool coated with TiN/Al2O3/TiCN highlighted itself for presenting better result in terms of the life of the tool and lower surface residual stresses of tensile at the beginning of tool life in relation to the tools coated with TiAlN and Al2O3/TiCN. The condition of vc = 80 m/min and f = 0,4 mm/rev highlighted itself among all the tested classes in terms of productivity. However, the f = 0,4 mm/rev is prejudicial to the superficial integrity, generating tensile stress and greater roughness
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
3
Campos, José Alexandre de. "Avaliação experimental do desgaste de canto durante o processo de eletroerosão do AISI H13". Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/1165.
Testo completoAbstract (sommario):
A fabricação de moldes e matrizes são ricas em detalhes e geometrias complexas, exigindo tecnologias mais inovadoras e precisas. Um dos processos que se destaca na fabricação de moldes e matrizes, é o de eletroerosão por penetração (Electrical Discharge Machining - EDM). A usinagem por descargas elétricas é classificada como um processo de fabricação de geometria não definida, onde a remoção de material é realizada por repetidas descargas elétricas entre dois eletrodos eletricamente condutores. O desgaste da ferramenta é um dos principais parâmetros de medida no desempenho da usinagem por EDM. O maior problema ocasionado pelo desgaste de canto do eletrodo é a mudança de geometria da ferramenta no decorrer da usinagem, alterando a tolerância geométrica e o dimensional da cavidade. O presente trabalho propõe avaliação dimensional do desgaste de canto do eletrodo, no decorrer da usinagem do processo de EDM, variando o ângulo de superfície frontal do eletrodo. Outro propósito é a criação de um índice, chamado de taxa de arredondamento, que leva em consideração as áreas de desgaste de canto do eletrodo em função da área removida de material da peça. Os resultados mostraram que os eletrodos de cobre, cobre tungstênio e grafite, tem um grande crescimento de raio de canto no inicio da usinagem, estabilizando esses valores com tempo maiores de processo. O ângulo de superfície frontal do eletrodo influência diretamente no desgaste de canto do eletrodo. Os eletrodos de grafite não apresentaram comportamento de arredondamento de desgaste de canto durante os ensaios. Para o índice de taxa de arredondamento os eletrodos de cobre tungstênio tiveram o menor valor apresentado na usinagem do AISI H13.The manufacture of molds and dies are rich in detail and complex geometries, requiring more innovative and precise technologes. One of the processes that stands out in the manufacture of molds and dies, is to EDM by penetration (Electrical Discharge Machining - EDM). The cutting by electrical discharge is classified as a non-defined geometry manufacturing process where material removal is carried out by repeated electrical discharge between two electrodes electrically conductive. The tool wear is a major measurement parameters in machining performance by EDM. The biggest problem caused by the electrode corner wear is the tool geometry change during the machining by changing the geometric tolerance and dimensional cavity. This paper proposes dimensional evaluation of the electrode corner wear, during the machining of the EDM process, varying the front surface of the electrode angle. Another purpose is to create an index, called rounding rate, which takes into account the areas of electrode corner wear due to the removed area of the workpiece material. The results showed that the copper electrode, copper tungsten and graphite, has a large corner radius growth at the beginning of machining, stabilizing these values with higher process time. The front surface of the electrode angle influence directly on the electrode corner wear. Graphite electrodes showed no corner wear rounding behavior during the tests. For rounding rate index tungsten copper electrodes had the lowest value presented in the machining of AISI H13.
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Vale, João Luiz do. "Influência da microestrutura de ferros fundidos na ocorrência de metal dobrado e no comportamento tribológico de superfícies brunidas". Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/2740.
Testo completoAbstract (sommario):
O presente trabalho discute a influência da microestrutura dos ferros fundidos, cinzento (FFC) e vermicular (FFV), na ocorrência de metal dobrado (FM) em superfícies brunidas e no comportamento tribológico em ensaio lubrificado do tipo anel sobre cilindro. As amostras de ferro fundido foram extraídas diretamente de um bloco de motor de combustão interna, em regiões de diferentes espessuras. O anel de pistão utilizado foi de aço inoxidável martensítico nitretado com perfil assimétrico e o óleo lubrificante foi o SAE 30 CF monoviscoso. A quantificação de sulcos e de metal dobrado (FM) foi realizada empregando-se uma metodologia baseada na literatura. Para a execução dos ensaios tribológicos foi projetada e construída uma adaptação para a montagem das amostras e controle de temperatura do óleo lubrificante. Um parâmetro para avaliação do desempenho tribológico foi proposto – índice de mérito tribológico (IMT) – que leva em conta coeficiente de atrito (COF) e alterações de topografia. Os ferros fundidos apresentaram microestruturas típicas. Contudo, observaram-se diferenças de morfologia e distribuição da grafita; com maior número de grafitas e menor fração de grafita para os materiais de parede fina. Observou-se FM nos platôs e nos sulcos das superfícies brunidas em todas as amostras. Quantificações mostraram que as larguras dos sulcos foram estatisticamente iguais e com alto percentual de obstrução. A quantificação de FM dos materiais mostrou maiores valores presentes na região do Spk (FMspk) para os FFC's. Os materiais de parede grossa apresentaram maiores valores de % FM dentro do sulco (%FM/Sulco) e este parâmetro teve forte e positiva correlação estatística com a fração de grafita. Evidências, obtidas em avaliações de seções transversais, corroboraram a relação entre FM e grafita. Constatou-se que o FM pode ser formado diretamente sobre a grafita ou, ainda, de forma indireta devido à extrusão desta fase. Ademais, verificou-se que a morfologia e orientação da grafita têm influência na formação do FM. Realizaram-se ensaios preliminares de curta duração de anel sobre cilindro para a avaliação da repetibilidade dos resultados de COF, os quais indicaram menor dispersão para condições com menores frequências e maiores forças normais. Avaliações da dinâmica do ensaio tribológico permitiram apontar relações de redução de COF durante os semi-ciclos de movimento e associá-las à teoria de lubrificação hidrodinâmica. O COF para ensaios de longa duração apresentou comportamento cíclico com transições. Estas transições foram associadas a mecanismos de formação-remoção-formação de tribofilmes de ZDDP. Os ensaios impuseram alterações nos parâmetros de rugosidade (principalmente com alisamento das superfícies) e redução do parâmetro de filme. O IMT evidenciou pouca influência da espessura do material; e melhor desempenho tribológico para os FFV's. A rotina de quantificação de FM mostrou limitação técnica devido ao alisamento da superfície, o que causa mudança na referência de alturas das superfícies brunidas. Ainda assim, verificou-se redução do %FM/Sulco e tendência de desobstrução do sulco. Contatou-se pouca influência do FM no comportamento do COF devido à similaridade dos parâmetros de FM entre os materiais. Contudo, o FM foi associado a um agente de abrasão à três corpos e apresentou forte correlação positiva do parâmetro de FMspk (no início do ensaio) com o parâmetro do IMT relacionado com a alteração de topografia.The present work discusses the influence of the microstructure of gray cast iron (GCI) and compacted graphite iron (CGI) on the occurrence of folded metal (FM) on honed surfaces and its tribological behavior in ring-on-cylinder test under lubrication. The cast iron samples were taken directly from an internal combustion engine block in regions of different thicknesses. The piston ring used was a nitrided martensitic stainless steel with asymmetrical profile and the lubricant oil was the SAE 30 CF. The quantification of grooves and folded metal (FM) was carried out using a methodology based on the literature. For the execution of the tribological tests an adaptation was designed and built for assembling the samples and for controlling the oil temperature. One parameter to evaluate the tribological performance was proposed - tribological merit index (TMI) - which considers the coefficient of friction (COF) and changes in topography. Each cast iron presented typical microstructures. However, differences in morphology and graphite distribution were observed; the samples from thinner wall presented higher number of graphite and less fraction of graphite. FM was observed on the plateaus and grooves of the honed surfaces in all samples. Quantification showed that the widths of the grooves were statistically similar and with a high percentage of obstruction. GCIs present a higher amount of FM in the Spk region (FMspk).The thicker wall samples presented a higher amount of FM in the grooves (% FM / Groove) and this parameter had a strong and positive statistical correlation with the graphite fraction. Evidences, obtained in cross section evaluations, corroborated the relationship between FM and graphite. It was verified that FM can be formed directly on graphite or indirectly due to the extrusion of this phase. In addition, its morphology and orientation influenced the occurrence of FM. Preliminary short-term tests were performed to evaluate the repeatability of COF results. These tests indicated less dispersion for conditions with lower frequencies and higher normal forces. Evaluations of the dynamics of the tribological test allowed to point out conditions to reduce the COF during the half-cycles of movement and to associate them to the theory of hydrodynamic lubrication. The COF for long-term tests presented cyclical behavior with transitions. These transitions were associated with formation-removal-formation mechanisms of ZDDP tribofilms. The tribological tests imposed changes on the roughness parameters (mainly with smoothness of the surfaces) and reductions on the film parameter. The thickness of samples affected little the TMI; and a better tribological performance of CGIs was detected. The FM quantification routine showed a technical limitation due to surface smoothing, which causes a change in the reference of heights of honed surfaces. Nevertheless, there was a reduction in %FM/Groove and tendency to clear the grooves. There was little influence of FM in COF behavior due to the similarity of FM parameters among the materials. However, FM was associated as a three-body abrasive agent and a strong positive correlation between the FMspk parameter (at the beginning of the test) and the TMI parameter was described.
Capitoli di libri sul tema "Surfaces (Technology) Mechanical wear. Metal-cutting"
1
Das, Suman Kalyan, Supriyo Roy e Prasanta Sahoo. "Corrosion and Wear Behavior of Electroless Nickel Coatings". In Handbook of Research on Developments and Trends in Industrial and Materials Engineering, 210–27. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1831-1.ch010.
Testo completoAbstract (sommario):
This chapter describes how corrosion is the degradation of a material due to a reaction with its environment. Wear is another deteriorating phenomenon which erodes the contacting surfaces of any mechanical component gradually. Although corrosion and wear are two different phenomenon they are often interdependent and in most practical situations take place simultaneously. Fortunately, several surface modification methods exist which can protect the surface of metal against corrosion and wear. Among them, electroless nickel coatings is a technology where a coating is applied without the use of external current source. The primary advantages of electroless coatings include uniform coating and ability to coat non-conductive materials. Electroless nickel coatings possess excellent properties such as high hardness, good wear resistance and corrosion resistance. The corrosion and wear behavior of these coatings mainly depend on bath ingredients, deposition conditions, heat treatment temperature, etc.
2
Méausoone, Pierre-Jean, e Alfredo Aguilera. "Inventory of Experimental Works on Cutting Tools’ Life for the Wood Industry". In Research Developments in Wood Engineering and Technology, 320–42. IGI Global, 2014. http://dx.doi.org/10.4018/978-1-4666-4554-7.ch009.
Testo completoAbstract (sommario):
Woodworking is based on a trinomial machine/piece/tool. For maximum quality of the manufactured piece, it is important not to separate this trinomial, but the limited life of tools prevents that permanent contact. This phenomenon is due to the wear of the cutting parts of the tools. The prevention of wear is based on two methods. The first is to anticipate the end point of tool wear, changing these after a fixed period, no matter what. The other school is to recognize the tool wear at the event: the tools are changed once they are really worn out, finding faults on manufactured parts. A worn tool generates pieces with non-compliant quality or even unusable. A deeper understanding of wear and its consequences would change the tool at the right time. The tool wear for wood is due to several phenomena interacting with each other. The first dominating phenomenon is a corrosive attack that decreases the mechanical strength of the surface. The second is an abrasive attack whose work is facilitated by the reduced resistance of the surface. Repeated shocks can be in the degradation of the cutting edge, temperature acting as amplifier to wear. Understanding of the wear patterns can characterize the life of tools by wear measurement to find ways to extend this period with development of tool coatings, while maintaining optimal conditions for woodworking to get the best finish.
Atti di convegni sul tema "Surfaces (Technology) Mechanical wear. Metal-cutting"
1
Henerichs, M., C. Dold, R. Voß e K. Wegener. "Performance of Lasered PCD- and CVD-Diamond Cutting Inserts for Machining Carbon Fiber Reinforced Plastics (CFRP)". In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62675.
Testo completoAbstract (sommario):
Carbon fiber reinforced plastics (CFRP) combine superior mechanical properties with a low weight. Consequently, this material is highly interesting for the aircraft as well as the automotive industry, leading to a massively increased application over the last years. However machining CFRP still faces different difficulties: The material is highly abrasive, most tool substrates and coatings face massive abrasive wear. Machining CFRP often results in many material defects like delamination, fiber pull-out, high surface roughness and burnt matrix material. Several technologies have been developed to combine ultra-hard tool surfaces and most adaptable cutting edge geometries. One of the most interesting approaches is laser machining of diamond cutting edges. The technology combines the wear resistance of thick layer diamonds with a geometrical flexibility so far known only for carbide tools. In the presented study, the wear resistance of different Polycrystalline Diamond (PCD) and Chemical Vapor Deposition (CVD)-Diamond grades machined with two different laser systems has been tested for machining CFRP. In comparison state-of-the-art grinded PCD cutting inserts are being tested. The comparison of machining characteristics is done by machining CFRP in a continuous turning process with a single fiber orientation. Machining forces are measured to evaluate tool wear. The resulting work piece quality is analyzed by measuring the surface roughness. The machined CFRP is a M21 resin system with an IMA-12K fiber from Hexcel©. Laser machined cutting inserts show equal or superior wear resistance compared to the grinded cutting inserts. In result today lasered cutting inserts are the machining tools available with the highest tool life time. In combination with the freely adaptable tool geometry, lasered cutting inserts are the superior tool system for upcoming machining tasks.
2
Bardetsky, Alexander, Helmi Attia e Mohamed Elbestawi. "Evaluation of Tool Wear Suppressive Ability of Lubricants Usein in Minimum Quantity Lubrication Application in High Speed Machining of Cast Aluminum Alloys". In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80597.
Testo completoAbstract (sommario):
The disadvantages of conventional metalworking fluids such as disposal problems, health problems and economic factors have led to the development of strategies to reduce their amount in metalworking. Recently, Minimum Quantity Lubrication (MQL) technology was developed and it seems to be a suitable alternative for economically and environmentally compatible production. It combines the functionality of lubrication with an extremely low consumption of lubricant and has a potential to replace metalworking fluids application in machining operations. The MQL lubricants are formulated with two major groups of additives; anti-wear (AW) additives and extreme pressure (EP) additives. When such lubricants are applied to the cutting zone, protective layers are formed on the interacting surfaces of the workpiece and the cutting tool. These layers prevent direct contact between the tool and chip surfaces, and, therefore reduce friction forces and tool wear. In order to utilize MQL to its full potential, it is essential to select appropriate lubricant composition for particular work material and machining parameters. The experimental study of different compositions of MQL lubricants is reported. The effectiveness of the lubricants are determined in terms of their ability to protect the cutting tool in high speed machining of cast aluminum alloys, which are widely used in automotive industry. The main objective of this research is to quantitatively evaluate the ability of lubricant’s additive composition to reduce the tool wear. This is reached through the comparison between the tool wear rate measured during the machining of aluminum cast alloy with the application of MQL, and the tool wear rate obtained in dry machining of the same alloy. Two kinds of the lubricants are evaluated; vegetable and synthetic. The content of AW and EP additives in each kind of lubricant was varied on three levels in order to capture the effect of the lubricant’s composition on tool wear. The result of the MQL lubricants evaluation is discussed and the recommendations for optimal lubricant composition are made.
3
Anand, M., M. Hadfield, JL Viesca e B. Thomas. "Experimental Study on the Effect of Marine Engine Lubricant Degradation on Tribological Performance of Cylinder Liner and Piston Rings Contact Using a Tuning Fork Technology Based Oil Sensor". In International Conference on Marine Engineering and Technology Oman. London: IMarEST, 2019. http://dx.doi.org/10.24868/icmet.oman.2019.009.
Testo completoAbstract (sommario):
An investigation was carried out to study the effect of changes in oil quality on its tribological performance using a tuning fork technology based oil sensor. In this research, a tribological testing system was commissioned, to simulate the piston ring-cylinder liner sliding contact, and to measure the lubricant condition in real-time using an oil sensor. Tribological contact between cylinder liners and piston rings in marine engines is the most affected region due to excessive thermo-mechanical stresses. At top dead centre, the effect of such stresses is at a maximum where piston-sliding speed is lowest, while the temperature is high due to fuel combustion, and radial load behind the piston rings compressing against the cylinder liner surface is at a maximum due to gas pressure and the compression fit of piston rings within the cylinder liner. At bottom dead centre, this effect is less severe due to a reduction in temperature and gas pressure on the piston rings, as the piston is positioned away from the combustion chamber. These two regions experience boundary lubrication conditions, where anti-wear and anti-friction additives are responsible for forming a protective lubricious film on sliding surfaces. At mid-stroke, piston-sliding speed is maximum, therefore, a full hydrodynamic film is formed in this region separating the piston rings and cylinder liner. The formation of oil film depends upon, the physical properties of oil (such as viscosity and density) under hydrodynamic lubrication conditions, and the oil chemistry (such as presence of additives in oil) under mixed or boundary lubrication conditions. Lubricants in marine engines undergo intense degradation in quality due to contamination with wear particles, water, soot, un-burnt fuel, coolant, and additives depletion. Such degradation of lubricants leads to a reduction in their capability to form a minimum thickness of oil film between two moving engine components to avoid direct metal-to-metal contact, which may cause wear. Therefore, monitoring the condition of marine engine lubricants is vital in order to predict any significant change in its quality. The results obtained from tribology testing and oil condition monitoring in the current research showed a good correlation and are useful to understand the performance of lubricants for piston ring-liner contacts.
4
Gopinath, Muvvala, Debapriya Patra Karmakar e Ashish Kumar Nath. "Monitoring of Molten Pool Thermal History and its Significance in Laser Cladding Process". In ASME 2017 12th International Manufacturing Science and Engineering Conference collocated with the JSME/ASME 2017 6th International Conference on Materials and Processing. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/msec2017-2657.
Testo completoAbstract (sommario):
The current study focuses on the process monitoring of thermal history and its significance in laser cladding technology. Thermal history of the molten pool during laser cladding was monitored using an IR-pyrometer and the molten pool life time, solidification shelf duration and cooling rates were calculated. Effect of these on three different cases was studied in brief: (a) Elemental segregation in nickel based super alloy, (b) Wettability between metal matrix and WC particles and (c) Decomposition of TiC particles in metal matrix. It was found that with slow cooling rate, formation of Laves phases in Inconel 718 became dominant which is detrimental to the mechanical properties. Also, slow cooling resulted in the decomposition of TiC particles resulting in poor wear properties of the coating. In contrast to the above two cases where slow cooling was found to be detrimental for mechanical properties of the coating, it increased wettability as well as bonding through diffusion between the WC particles and the metal matrix. Also the effect of presence of TiC and WC in metal matrix on molten pool thermal history was studied. The microstructures, elemental segregations and fractured surfaces were characterized using SEM and EDS analyses.
5
Dues, Joseph Francis. "Connecting With Industry". In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42489.
Testo completoAbstract (sommario):
In an era of tight budgets, Universities must plan their capital spending on lab equipment carefully. This process is even more critical for smaller colleges and satellite locations. To address the problem of a limited budget for lab equipment but a strong need for expanded labs to meet minimum course requirements, faculty contacted local industry to ask for help. The Mechanical Engineering Technology department includes a metallography lab as one of its core learning objectives in the freshman level Materials I course. The metallography lab consists of mounting, grinding, polishing and etching a metallographic specimen to identify features of the specimen’s microstructure. Unfortunately, lab equipment was not available for these tasks at one of the University’s satellite locations. However, through contacts with the school’s Industrial Advisory Board, a local company offered to host the laboratory and allow students to use its metallography facility. Conforma Clad, in New Albany, IN, applies very hard coatings to protect metal surfaces subject to wear and abrasion. For quality control purposes, they perform metallographic examinations of the applied coatings. Conforma Clad engineers demonstrated the preparation of the metallographic specimens and the analysis of their microstructure and then let students prepare and view their own specimens. This experiment showed the students the procedures and equipment needed to create pictures of a metal’s microstructure. By preparing the samples themselves, they gained an appreciation of the skill and technique required to successfully view the microstructure. This paper describes the collaboration the MET faculty used to add laboratory experiments without capital expenditures by connecting with local industry. Students benefited by gaining access to the operations and facilities of a local company as well as the knowledge gained by performing the metallography lab. The paper concludes with an evaluation of the experience and the improvements planned for the coming year.
6
Wang, Yachao, Jing Shi e Xinnan Wang. "Influences of Silicon Crystal Anisotropy in Nano-Machining Processes Using AFM". In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65674.
Testo completoAbstract (sommario):
Atomic force microscope (AFM) machining has the potential to become an essential technology for manufacturing micro/nano-scale devices. In literature, this technique has been successfully employed to machine various types of materials, including semiconductor materials and metals. However, the effect of material anisotropy in terms of crystal direction is rarely considered in the existing studies. In this paper, we conduct nano-scratching experiments on the (1 0 0) plane of single crystal silicon surface with a diamond tip in an AFM machine. Three levels of crystal direction of nano-scratching are considered. Four levels of normal loading are applied. Machining performances are mainly evaluated by the groove morphology. Also, the wear coefficients and scratch ratio are calculated to the anti-wear performance. Based on the pile up volume and cutting volume respectively, the presence of the ploughing and cutting mechanisms is determined. The experiment results indicate that the applied normal load significantly affect the groove depth and debris morphology. The scratching direction has a pronounced effect on the friction coefficient and the calculated scratching hardness. By observing the debris morphology and cracks formation, the dependence of ductile to brittle transformation mechanism of silicon machining on the crystal direction is also discussed.
7
da Silva, Hebert Roberto, Valtair Antonio Ferraresi e Rosenda Valdes Arencibia. "Operational Aspects of Coatings Welds: Erosive Wear and Cavitation". In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70169.
Testo completoAbstract (sommario):
The GMAW process using two wires is an alternative to a coating process when high productivity is desired. The potential variants emerging from this process are GMAW cold wire and GMAW double wire. One of the greatest difficulties is the setting of its parameters, which duplication compared to conventional GMAW and also act in a dependent manner. A greater understanding of the technology applied to coatings on turbines in various positions is critical to master the process and its variables for enhancing industrial applications. This study involves an experimental evaluation to verify the influence of some variables on the profile of cord and wear resistance. This paper proposes making deposits with weld metal AWS 308LSi stainless steel and alloys of cobalt (Stellite 6 and 21) plates in carbon steel SAE 1020 in the flat positions. The wear characterization in the lining is used to determine the hardness and surface topography. It is concluded that cobalt alloys have superior resistance to erosive damage, with emphasis on Stellite 21 with respect to erosion and Stellite 6 with respect to cavitation. Mixtures of austenitic stainless steel and cobalt alloys have intermediate wear values. Therefore, it is essential to study welding processes with multiple wires, as proposed in this paper, to determine the optimal combination of alloys for resistance to cavitation-erosion phenomena.
8
Zhao, Zheng, Beibei Feng, Xingtuan Yang e Yanfei Sun. "Prospect of MAO Technology Application in Nuclear Power Industry". In 2013 21st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icone21-15435.
Testo completoAbstract (sommario):
Micro arc oxidation (MAO) technology known as a newly surface treatment technology has got a widely application in the field of aviation, aerospace, automotive, electronics, and medical industry. Strength, toughness, hardness and corrosion of valve metal such as aluminum, magnesium, copper, zinc, zirconium and their alloys can be greatly improved by MAO technology. This paper tries to probe into the feasibility of using MAO technology in nuclear power industry. Aluminum and its alloys are used as structural materials such as the cladding of reactor fuel and all kinds of pipes in the low nuclear reactor. Zirconium alloys are widely used for the fuel cladding, cannula, catheter and other components of the fuel assemblies. Titanium and its alloys offer a unique combination of desirable mechanical properties which makes them to be the candidate materials for structural application in the field of nuclear energy. The surface of all these materials may be destroyed which increasing the risk of the nuclear accident due to the severe serving conditions. As a result, it is necessary to improve the corrosion and wear resistance behavior. With the urgent requirements of safety and durability of nuclear reactor, MAO technology must have a broad prospect in nuclear industry.
9
Hildering, Sven, Markus Michalski, Ulf Engel e Marion Merklein. "Tool Load Sensitivity Against Multidimensional Process Influences in Microblanking of Thin Metal Foils With Silicon Punches". In ASME 2015 International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/msec2015-9206.
Testo completoAbstract (sommario):
The continuous trend towards miniaturization of metallic micro parts of high quality at low costs results in the need of appropriate production methods. Mechanical manufacturing processes like forming and blanking meet these demands. One major challenge for the application of them are so called size effects. Especially the downsizing of the required manufacturing tools and adequate positioning causes higher effort with increasing miniaturization. One promising approach for downsizing of tools is the transfer of knowledge from microsystems technology. This study shows the process behavior of etched silicon punches in microblanking operations. For the application as tool material especially the brittle material behavior and sensitivity against tensile stresses have to be considered. These mechanical loads favor wear in form of cracks and breaks at the cutting edge of the punch and decrease tool life. In a special test rig these wear phenomena were observed in microblanking of copper foils. Although high positioning accuracy between tools and workpiece can be assured within this test rig, scatter of tool life is observable. Therefore, a finite element analysis of the tool load in the microblanking process with special respect to tensile stresses was performed. Within the 3D finite element model multidimensional positioning errors like tilting between punch and die were integrated. Their influence on the tool load in form of increasing tensile stresses is evaluated with respect to the type and magnitude of positioning error. Furthermore, the effects of small outbreaks at the cutting edge on the process behavior and tool load are analyzed.
10
Ochmann, Lukas, Moh'd M. Amro, Bernd Gronde, Gundula Fischer, Silke Weber e Dirk Martin. "Development of Plasma Sprayed Coatings to Improve the Erosion Resistance of Wire Wrapped Screens". In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21158-ms.
Testo completoAbstract (sommario):
Abstract The installation of sand screens in wells can fail in one of two ways: by causing an unacceptable high pressure drop in the near wellbore area or by losing the ability to retain particles. Four mechanisms can lead to a failure: plugging, corrosion, erosion and mechanical deformation. To increase the lifetime under erosive conditions, a coating for wire wrapped screens was developed and tested. Erosion occurs, when formation particles hit the screen surface with high velocities or by continuous production of fines through the screen openings. The screen openings must keep a specified size in order to control the formation sand or gravel pack. If the opening size increases due to erosion, more particles are produced and erosion increases. A newly developed coating is put on the outside (i.e. facing the formation) of standard wire wrapped screens to make the slots resistant against erosion. The coating consists of ceramic or hard metal and is applied by plasma spraying. An extensive development and verification program was conducted to guarantee defined slot widths, corrosion resistance and mechanical strength of coating and screen. A test facility was built to investigate the erosion resistance of sand screens. It consists of a flow loop to circulate a slurry of water and particles through 2″ coupons. Samples of standard wire wrapped, metal mesh and coated screens were tested. The tests were conducted with flow velocities of up to 18.5 m/s and particles of up to 100 micrometer for up to 60 h. The screens where compared under consideration of optical criteria, mass loss and functionality. The coated screens showed no sign of wear on the outside and kept their initial slot size. The slots of uncoated wire wrapped screens more than doubled in some places, when eroded under the same conditions. To test the functionality of the samples, sand retention tests were conducted before and after erosion. Since there were no changes in slot width, the coated screens show the same retention capabilities before and after erosion, while metal mesh screens that were eroded under the same conditions lost their ability to retain sand. The newly developed coating improves the resistance against erosion, is able to withstand corrosive well environments and has mechanical properties suitable to be safely installed in any well. Therefore the coating has the ability to improve the lifetime of screens under erosive conditions.