Dry sliding friction and wear response of WC-Co hardmetal pairs in linearly reciprocating and rotating contact

This paper presents an experimental evaluation of friction and wear properties of WC-Co cemented carbides. A comparison is made between unlubricated rotating and linearly reciprocating pin-onplate sliding pairs. The plate specimens were WC-10wt%Co grades surface finished by polishing or sequential wire-EDM steps, whereas WC-6wt%Co pins were used as counter body. The tests were carried out at room temperature using a sliding speed of 0.30m/s and mean Hertzain contact pressures of 1.76 and 2.08 GPa, i.e., normal contact loads of 15N and 25N, respectively. The worn surfaces on plate samples were quantified in terms of 2–D wear profiles obtained by means of surface topography scanning equipment. Wear mechanisms such as polishing and abrasion were identified using optical microscopy. Inferior tribological characteristics for wire-EDM surface finish compared to polishing were found. Higher friction coefficient and wear levels were measured in unidirectional rotating sliding experiments compared to linearly reciprocating test conditions

Tribological behavior of wire-EDM'ed ZrO2-composites and cemented carbides

Five ZrO2-based composites (ZrO2-WC, ZrO2-TiCN and ZrO2-TiN grades) and five WC-Co cemented carbide grades were machined by wire-EDM and tested on a linearly reciprocating sliding pin-on-flat tribometer PLINT TE77 in dry conditions against WC-6wt%Co pins. Measurement of friction coefficient and penetration depth due to wear was performed continuously. The results revealed a strong influence of the secondary phase, surface finish, chemical and mechanical properties on the tribological characteristics of the ZrO2-based composites and cemented carbides. WC10Co(Cr/V) displayed superior wear resistance compared to the other grades. The lowest coefficient of friction was encountered with ZrO2-WC

Correlation between Microstructural Alteration, Mechanical Properties and Manufacturability after Cryogenic Treatment: A Review

Cryogenic treatment is a supplemental structural and mechanical properties refinement process to conventional heat treatment processes, quenching, and tempering. Cryogenic treatment encourages the improvement of material properties and durability by means of microstructural alteration comprising phase transfer, particle size, and distribution. These effects are almost permanent and irreversible; furthermore, cryogenic treatment is recognized as an eco-friendly, nontoxic, and nonexplosive process. In addition, to encourage the application of sustainable techniques in mechanical and manufacturing engineering and to improve productivity in current competitive markets, cryo-treatment can be considered as a promising process. However, while improvements in the properties of materials after cryogenic treatment are discussed by the majority of reported studies, the correlation between microstructural alteration and mechanical properties are unclear, and sometimes the conducted investigations are contradictory with each other. These contradictions provide different approaches to perform and combine cryogenic treatment with pre-and post-processing. The present literature survey, mainly focused on the last decade, is aimed to address the effects of cryogenic treatment on microstructural alteration and to correlate these changes with mechanical property variations as a consequence of cryo-processing. The conclusion of the current review discusses the development and outlines the trends for the future research in this field

Reciprocating friction and wear behavior of WC-Co based cemented carbides manufactured by electro-discharge machining

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An investigation of sliding wear of Ti6Al4V

Thesis (MScEng)--Stellenbosch University, 2012.ENGLISH ABSTRACT: Sliding wear is a complicated form of wear involving different factors. The factors affecting the process are the mechanical properties of the materials, sliding distance, sliding speed, and normal force applied to the contact. An experimental study was conducted to assess the performance of Ti6Al4V in self-mated and various counterface material contact couples subjected to linear reciprocating dry sliding motion. The normal force was varied for all the experiments to understand the effect it had on specific couples. Sliding wear experiments were also conducted on cemented carbides coupled with Ti6Al4V. In certain applications carbide coatings are used and could possibly come into contact with Ti6Al4V. Cemented carbides used in the study were manufactured through spark plasma sintering and liquid phase sintering. An in depth study was conducted to assess the spark plasma sintered materials and compare these to those manufactured through liquid phase sintering. The experimental study revealed that an increase in normal force, in sliding experiments, led to an increase in friction and wear volume loss of the Ti6Al4V pin. In addition the experiments found that Ti6Al4V was prone to adhesion and surface oxidation.AFRIKAANSE OPSOMMING: Glyslytasie is 'n gekompliseerde slytasievorm wat verskillende faktore behels.Die faktore wat die proses beïnvloed is die meganiese eienskappe van die materiale,gly-afstand,glyspoed en normale druk(krag) wat op die kontakoppervlakte toegepas word. 'n Eksperimentele studie om die werksverrigting van Ti6Al4V in verenigde en verskeie teenwerkende materiaal kontakpare wat onderwerp is aan lineêre omgekeerde droë gly-aksie te assesseer is uitgevoer.Die normale krag vir al die eksperimente om die effek wat dit op die spesifieke pare gehad het te verstaan is gevarieer. Glyslytasie-eksperimente is ook op gesementeerde karbiedes wat met Ti6Al4V gekoppel is,uitgevoer. In sekere toepassings is karbiedlae gebruik en kon moontlik met Ti6Al4V in kontak gekom het. Gesementeerde karbiedes wat in die studie gebruik is, is deur vonkplasmasinter en vloeibare fase-sinter vervaardig. 'n Indieptestudie is ook uitgevoer om die vonkplasmasintermateriale en dié materiale wat deur vloeibare fasesinter vervaardig is te vergelyk. Die eksperimentele studie het getoon dat 'n toename in normale krag in glyeksperimente gelei het tot 'n toename in wrywing en slytasievolumeverlies van die Ti6Al4V pin. Bykomend tot die eksperimente is gevind dat Ti6Al4V geneig was tot adhesie en oppervlakteoksidasie

Tungsten Carbide

Tungsten Carbide - Processing and Applications, provides fundamental and practical information of tungsten carbide from powder processing to machining technologies for industry to explore more potential applications. Tungsten carbide has attracted great interest to both engineers and academics for the sake of its excellent properties such as hard and wear-resistance, high melting point and chemically inert. It has been applied in numerous important industries including aerospace, oil and gas, automotive, semiconductor and marine as mining and cutting tools, mould and die, wear parts, etc., which also has a promising future particularly due to enabling to resist high temperature and are extremely hard

An experimental and simulation study on parametric analysis in turning of inconel 718 and GFRP composite using coated and uncoated tools

Process simulation is one of the important aspects in any manufacturing/production context because it generates the scenarios to gain insight into process performance in reasonable time and cost. With upcoming worldwide applications of Inconel 718 and Glass Fiber Reinforced Polymer (GFRP) composites, machining has become an important issue which needs to be investigated in detail. In turning of hard materials (such as Inconel 718), cutting tool environment features high-localized temperatures (~1000ºC) and high stress (~700 MPa) due to contact between cutting tool and work piece. The tool may experience repeated impact loads during interrupted cuts and the work piece chips may chemically interact with the tool materials. Therefore, the use of coated tool is preferred for turning of Inconel 718. It is observed that performance of machining process is influenced by different machining parameters such as spindle speed, depth of cut and feed rate as in case of turning. Material removal rate (MRR) and flank wear in turning of Inconel 718 using physical vapour deposition (PVD) and chemical vapour deposition (CVD) coated on carbide insert tool are reported. A simulation model based on finite element approach is proposed using DEFORM 3D software. The simulation results are validated with experimental results. The results indicate that simulation model can be effectively used to predict the flank wear and MRR in turning of Inconel 718. For simultaneous optimization of multiple responses, a fuzzy inference system (FIS) is used to convert multiple responses into a single equivalent response so that uncertainty and fuzziness in data can be addressed in an effective manner. The single response characteristics so generated is known as Multi Performance characteristic Index (MPCI). A non-linear empirical model has been developed using regression analysis between MPCI and process parameters. The optimal process parameters are obtained by a recent population-based optimization method known as imperialistic competitive algorithm (ICA). Analysis of variance (ANOVA) is performed to identify the most influencing factors for all the performance characteristics. The optimal conditions of process parameters during turning of Inconel 718 and GFRP composites are reported. It is observed that flank wear is combatively less when machined with PVD coated tool than CVD coated tool in turning of both Inconel 718 and GFRP composite