Tribology in Industry

341-347

Authors: M. Banjac, A. Vencl, S. Otović

Tribology, as the scientific and professional discipline within the mechanical engineering, studies phenomena and processes on the interacting surfaces, in direct and indirect contact and in relative motion. It includes the study and application of the principles of friction, wear and lubrication, as well as phenomena connected with these processes. Given that a process involving friction is always accompanied by transformation of energy, more precisely an energy dissipation process which generates entropy, the concept of thermodynamic entropy production analysis represents one of appropriate tools for studying and analysing the behaviour of complex friction and wear processes. This paper presents a review of published works in which the thermodynamic approach was used in analysing the friction and wear processes in tribosystems.

354-360

Authors: S. Petrović Savić, D. Adamović, G. Devedžić, B. Ristić, A. Matić

Total knee replacement (TKR) is considered, during last years, as a very successful surgical technique for removing knee joint deformities and eliminating pain caused by cartilage damage. In literature, as primary causes for knee joint endoprothesis damage are cited complex movements which cause occurrences of complex stress conditions, sagital radius conformity, sliding, types of materials etc. Aim of this study is analysis of contact stresses that occur on tibial implant for 15°, 45° and 60° knee flexion and 50 kg, 75 kg, 100 kg and 125 kg weight. Knee joint prosthesis model and finite elements method (FEM) analysis are done in software Catia V5. For this analysis we used ultra-high molecular weight polyethylene (UHMWPE) for tibial implant material and AISI 316, AISI 317, AISI 321, 17-4PH, CoCrMo, Ti6Al4V and SAE A-286 for femoral component materials. Results show that area of maximal contact stress is identified in medial and lateral part of tibial implant. Von Mises stress values vary regarding of flexion degree and weight, but values are approximate for types of chosen materials. Contact stress location corresponds to damage that occur on tibial implant during exploitation.

375-383

Authors: D. Kekes, P. Psyllaki, M. Vardavoulias, G. Vekinis

Composite coatings with five different proportions of WC-Co/Cr and NiCrFeBSiC components were deposited on stainless steel by HVOF spraying. Cavitation erosion tests were performed and the material removal micro-mechanisms were identified by SEM of both the eroded areas and the specimens’ cross-sections. Waves’ propagation and deflection at the weak interfaces within the coatings resulted in local tensile stresses perpendicular to the interface direction that eventually led to material removal. Such weak interfaces are the boundaries of the carbide particles with the metal binder within the same splat, those between splats along the same layer and those between successively deposited layers.

394-405

Authors: M.S. Priyan, P. Hariharan

In this study, commercially available FeSiNiCr and FeBCr alloy powders were designed with suitable compositions, gas atomized and then coated on gray cast-iron substrate. The microstructures of the feed stock Fe based alloy powders and the coatings were investigated by means of optical microscopy (OM), X-Ray diffraction (XRD), Thermogravimetric analysis (TGA) and Scanning Electron Microscopy (SEM). In the present study, both the coating materials experienced two-body wear mechanisms. The results showed that for loads of 0.05 N, 0.1 N and 0.2 N, the wear resistance of FeBCr coating was less than FeSiNiCr by 44 %, 40 % and 31 %, respectively. The results indicated that the coated substrates exhibited lower corrosion current densities and lower corrosion rates, when placed in 20 wt.% H2SO4 solutions. In addition, the use of optimal spraying parameters/conditions gave improvements to the corrosion resistance of the substrates that had been treated with the crystalline coating.

419-427

Authors: M. Bastiurea, M.S. Rodeanu Bastiurea, G. Andrei, D. Dima, M. Murarescu, M. Ripa, A. Circiumaru

Some polymers show low thermal properties which can be improved by adding various types of materials. Using nanoparticles, an enhancement of thermal properties can be obtained, even for small contents of additives. The evaluation of thermal properties of polymer composites with graphene can be achieved relying on Differential Scanning Calorimetry tests (DSC). This work presents a few conclusions resulting from DSC tests of the polyester composites with graphene and graphite.

437-450

Authors: L.L. Badita, G. Gheorghe, L. Capitanu

Hip prosthesis is a complex mechanical biotribosystem with multiple functions. Under the action of cyclic dynamic loadings, developed in a biological adversely environment, it can lose the optimal functionality during the time. To improve mechanical characteristics of hip prostheses we deposited TiN films on SS316Lsteel substrates by pulse laser deposition method (PLD). Adhesion strength of the layer on the substrate was evaluated by scratch tests accompanied by different microscopy methods. Following these studies, we believe that the essential factor for increasing the hardness of femoral heads with thin layers is to provide a strong adherent coating to the substrate using PLD.

465-474

Authors: C. Cristescu, C. Dumitrescu, R. Radoi, L. Dumitrescu

The article presents some aspects of developing, within INOE 2000-IHP, of an experimental research on the determination of frictional forces that occur in the mobile sealings of the pistons, between the piston sealings and the inner liner of hydraulic cylinders. In the first part of the paper, are presented some specific elements of the experimental device and of the testing stand which have been developed, while in the second part are presented some graphical results obtained in experimental research, as well as some comments on them. This developed experimental research marks the continuing of a major action on the tribological behavior of mobile hydraulic seals, which are frequently used in the construction of hydraulic cylinders.

229-235

Authors: G.N. Krishna, S.K. Roy Chowdhury, A. Biswas

A good deal of work carried out in recent past has shown that the triboelectromagnetic radiation produced during peeling of a scotch tape, breaking rock sugar with a hammer, peeling of mica sheets etc. may extend even to X-ray energies. Work on peeling of scotch tape has been particularly successful in demonstrating visible X-ray emission in modest vacuum. The present work looks at the possibility of X-ray emission during rubbing of metals and other selected material pairs in air. Experimental results indicate that X-ray emission indeed occurs during rubbing of even common engineering metals and also other selected material pairs under certain restricted rubbing configurations. It was observed that X-rays could be detected when one of the rubbing surfaces was a thin metal sheet. It was also observed that with the increase in sliding speed X-ray emission increased whereas the increase in load did not have much influence on the emission. Vibration at the contact was found to be an important influential parameter. With the increasing vibration X-ray emission increased. This X-ray emission at the rubbing contact between common engineering materials, if exploited properly, can be of significant use in in-situ monitoring of tribological processes.

244-258

Authors: D. Prasad, S.V. Subrahmanyam, S.S. Panda

Hydrodynamically heavily loaded rigid cylindrical rollers, lubricated by a thin compressible fluid film, are investigated for normal squeezing motion and cavitations. The lubricant is assumed to follow the non-Newtonian power-law fluid model where consistency and density of the lubricant vary with one dimensional pressure and temperature. The modified Reynolds pressure equation and thermal energy equation are derived and solved simultaneously by R-K Fehlberg method. Secant method is also applied in order to enforce the boundary condition at the outlet. It is observed that temperature has significant effects on consistency and density both. It is also to be noted that compressibility effect is even more significant when squeezing is taken into account.

269-280

Authors: P.C. Mishra

This paper presents studies related to piston compression ring tribology and the theoretical and experimental works developed to analyze ring-liner contact friction. The literatures revealed that the simulation and experimental work are more independently investigated. The correlation of modeling output with experimental output is presented in limited number of research works. The experimental work to capture data from a running engine is also in basic level.

287-292

Authors: V. Lazić , R. Čukić, S. Aleksandrović, D. Milosavljević, D. Arsić, B. Nedeljković, M. Đorđević

Research in the field of hard-facing of various parts mechanical systems' are being done for technical and techno-economic reasons. The reasons for introducing the new reparation technologies by hard-facing are numerous: three quarters of all the mechanical parts of engineering could be regenerated or manufactured by hard facing; the working life of the repaired part reaches or even exceeds the working life of a new part, while the working life of the hard faced manufactured part surpasses several times the working life of the new part manufactured by some other technology. Large number of damaged and, frequently even broken parts, cause terminations of the working process. Thus, due to difficulties in procurement of new, mainly imported parts, the alternative solution must be applied. It is sown that the a proper choice of the hard-facing technology is related to the complex procedure of checking the quality of the hard faced layer, what indicates that the reparatory operations could be performed only in specialized regeneration workshops, which are furnished with adequate equipment and corresponding expert and skilled staff. The estimated net benefit for the analyzed parts is exceptionally high, regardless of the fact that the additional external and internal effects have not been quantified.

300-307

Authors: M. Jeremić, M. Matejić, B. Bogdanović, B. Tadić, D. Miloradović, D. Miljanić

This paper is analyzing the impact of the construction element position of ship winch drum on the effects of torque transmission by friction in the mechanization welding process. The driving and driven wheels (construction elements) were examined for the general case of the load distribution. Based on this examination, the construction of the device that should provide the reliable torque transmission and the movement of the drum in the process of its welding are proposed. This construction is characterized by a high level of flexibility and ability to change the friction torque based on changing drum position in regard to the driving and driven wheels (construction elements). With this new construction, problems related to the movement synchronization are avoided, unlike the all previously known constructions of this type, which lead to the positive impact on the wear intensity of friction gears.

316-325

Authors: D. Ćatić, J. Glišović, J. Miković, S. Veličković

The introduction of the paper gives the basic concepts, historical development of methods of Fault Tree Analysis - FTA and Failure Modes, Effects and Criticality Analysis - FMECA for analysis of the reliability and safety of technical systems and importance of applying this method is highlighted. Failure analysis is particularly important for systems whose failures lead to the endangerment of people safety, such as, for example, the braking system of motor vehicles. For the failure analysis of the considered device, it is necessary to know the structure, functioning, working conditions and all factors that have a greater or less influence on its reliability. By formation of the fault tree of drum brakes in braking systems of commercial vehicles, it was established a causal relation between the different events that lead to a reduction in performance or complete failure of the braking system. Based on data from exploitation, using FMECA methods, determination of the criticality degree of drum brake’s elements on the reliable and safe operation of the braking system is performed.

109-116

Authors: A. Mukhopadhyay

Ethylene Propylene Diene Monomer (EPDM) rubber emerges as a dominant elastomer for major engineering applications. The major properties of EPDM are its outstanding heat, ozone and weather resistance ability. It has a good resistance to polar substances and steam condition too. In automobiles EPDM rubber has a common use as seals. This includes door seals, window seals, trunk seals and sometimes hood seals. Frequently these seals are the source of noise due to the movement of the door versus the car body. This is due to friction between the EPDM rubber parts and the mating surfaces. Thus, the contact iteration between the rubber sealing and the indenting object must be known to optimize the performance of rubber sealing. However, it is need less to mention that the behaviour of any viscoelastic material is very difficult to be predicted. In the present work various tribo-characteristics of EPDM rubber of different hardness have been evaluated utilizing the available laboratory test facilities in the Jadavpur University, Kolkata, India. Compression tests have been carried out using ‘Instron’ to determine the flow behaviour of EPDM rubber of different hardness both in dry as well as under different conditions of lubrication. The flow behaviour like load -vs.- elongation curves, true stress -vs.- elongation curves and true stress -vs.- true strain curves have been drawn from the experimental data. Abrasive wear behaviour has been evaluated using a two-body abrasion tester and the pattern abrasion has been appraised through SEM/EDAX study. Experimental results reveal that the hardness of EPDM rubber has significant effect on the flow behaviour and wear characteristics. The hardness, again, depends on the proportion of carbon black (CB) content. Thus it can be stated that the flow behaviour can be governed by controlling the CB concentration in the EPDM rubber. Based on the experimental results conclusion has been drawn accordingly. Some of the important tribo-characteristics of EPDM have been highlighted. Light has also been shed on various possible areas of further researches those should be undertaken in the future to come.

127-133

Authors: S. Baskar, G. Sriram

The friction and wear behavior of journal bearing material has been investigated using pin on disc wear tester with three different lubricating oils i.e. synthetic lubricating oil (SAE20W40), chemically modified rapeseed oil (CMRO), chemically modified rapeseed oil with Nano CuO. Wear tests were carried out at maximum load of 200 N and sliding speeds of 2 – 10 m/s. The results showed that the friction and wear behavior of the journal bearing material have changed according to the sliding conditions and lubricating oils. The journal bearing material has a lower friction coefficient for CMRO with Nano CuO than other two oils. Higher wear of journal bearing material was observed in SAE 20W40 and CMRO. Worn surfaces of the journal bearing material with three lubricating oils were examined using scanning electron microscope (SEM) and wear mechanisms were discussed.

144-154

Authors: U.A. Zia, A.A. Baqai, W. Akram

Frictional wear is one of the most common causes of material failure. One of the most common techniques to overcome this is to lubricate the surfaces in contact using an optimum amount of appropriate lubricant. Same technique is utilized in the present case to overcome the problem of frictional wear between two parallel surfaces subjected to high acceleration. The lubrication solution proposed is a modification of “Numerical model for mixed lubrication” presented in 1990s. Present research is an extension of author’s previous work in the same. Here the smooth surfaces of the previous research have been replaced with rough surfaces having same surface roughness value. Also in order to study the effect of temperature the viscosity of lubricant is taken for different temperatures. Keeping in view the problem constraints as explained in section 3, certain modifications are proposed in the model of mixed lubrication. Outcome of the research is a graphical pattern showing the lubricant film thickness required at different positions between the contacting surfaces. Different grades of Krytox are used for the solution as it is nonflammable, anticorrosive Perfluoropolyether based grease, commonly used for high temperature cases. The results obtained by the numerical model are compared and found well-in-accordance with the experimental data available and with the analytical predictions made by scholars in the past, which verifies the applicability of the model chosen for solution.

163-171

Authors: H.M. Mobarak, M. Chowdhury

Increasing environmental awareness and demands for lowering energy consumptions are strong driving forces behind the development of the vehicles of tomorrow. Without the advances of lubricant chemistry and adequate lubricant formulation, expansion of modern engines would not have been possible. Considering environmental awareness factors as compared to mineral oils, vegetal oil based biolubricants are renewable, biodegradable, non-toxic and have a least amount of greenhouse gases. Furthermore, improvement in engine performance and transmission components, which were impossible to achieve by applying only lubricants design, is now possible through diamond like carbon (DLC) coatings. DLC coatings exhibit brilliant tribological properties, such as good wear resistance and low friction. In this regard, tribological performance of a-C: H DLC coating when lubricated with Canola vegetal oil has been investigated by the help of a ball-on-flat geometry. Experimental results demonstrated that the a-C: H DLC coating exhibited better performance with Canola oil in terms of friction and wear as compared to the uncoated materials. Large amount of polar components in the Canola oil significantly improved the tribological properties of the a-C:H coating. Thus, usage of a-C: H DLC coating with Canola oil in the long run may have a positive impact on engine life.

181-187

Authors: M. Kandeva, D. Karastoianov, B. Ivanova, V. Pojidaeva

Friction and wear of 10 types Ni chemical coatings, with and without heat treatment, containing nano-diamond particles of various size – 0;5 nm; 100 nm; 200 nm and 250 nm, are studied in the paper. Procedure and laboratory device for friction investigation in starting regime were developed. Experimental results for the influence of the particle size on the static friction force and the change of friction coefficient have been obtained. Abrasive wear has been studied by means of the procedure developed by the authors for the study of above coatings under conditions of dry friction on surfaces with fixed abrasive. The obtained results are related to the parameters linear wear, wear rate and wear-resistance. A part of this study is connected with the tasks on the 7 FP Project „Acom In (Advanced Computing Innovations)” coordinated by the Institute of Information and Communication Technologies at the Bulgarian Academy of Sciences, and the other part is carried out under the Project ДУНК-01/3 “University R&D Complex for innovation and transfer of knowledge in micro/nano-technologies and materials, energy efficiency and virtual engineering” funded by the Bulgarian Ministry of Education and Science.

195-203

Authors: K.K. Alaneme, B.O. Fatile, J.O. Borode

The mechanical and corrosion behaviour of Zn-27Al alloy based composites reinforced with groundnut shell ash and silicon carbide was investigated. Experimental test composite samples were prepared by melting Zn-27Al alloy with pre-determined proportions of groundnut ash and silicon carbide as reinforcements using double stir casting. Microstructural examination, mechanical properties and corrosion behaviour were used to characterize the composites produced. The results show that hardness and ultimate tensile strength of the hybrid composites decreased with increase in GSA content. Although the % Elongation somewhat decreased with increase the GSA content, the trend was not as consistent as that of hardness and tensile strength. The fracture toughness of the hybrid composites however, increased with increase in the GSA content of the composites. In 3.5 % NaCl solution, the composites were resistant to corrosion with some of the hybrid composite grades containing GSA exhibiting relatively superior corrosion resistance to the grades without GSA. In 0.3M H2SO4 solution, the composites were generally a bit more susceptible to corrosion (compared to 3.5 % NaCl solution), but the effect of GSA content on the corrosion resistance of the composites was not consistent for the Zn-27Al alloy based composites.

211-219

Authors: P.C. Mishra

Performance characteristics of a rough elliptic bore journal bearing are studied. The bearing bore of isotropic roughness orientation is characterized by stochastic function and the film geometry is quantified to elliptic shape. There after the Reynolds equation and energy equation are descretized for pressure and temperature respectively. A finite difference model is developed to evaluate hydrodynamic pressure and oil temperature. Solution to this model is done using effective influence Newton-Raphson method. Performance parameters such as load bearing ability, friction, flow-in and side leakages are computed and discussed.

3-8

Authors: E. Zdravecká, M. Marton, A. Gmiterko, J. Tkáčová

The application of hard wear-resistant coatings is expanding into various sectors of industry to protect tools and other components from failure caused by wear and corrosion. However, in forming industry it is still rather an exception than a rule to find coated forming dies. This study has objectives to investigate wear behaviour of P/M Vanadis 6 ledeburitic steel with PVD-TiN and TiCN coatings. The tests were carried out in the laboratory and industrial process conditions. The obtained results under operating conditions show that the application of PVD coatings appears as a very effective method for increasing the lifetime and wear resistance of cold stamping dies.

17-21

Authors: C. Georgescu, L. Deleanu, C. Pirvu

This study presents the influence of the normal force on the surface quality of the friction couple steel – polybutylene terephthalate (PBT) + 10 % polytetrafluoroethylene (PTFE). There were calculated the average values of the amplitude and functional parameters, as obtained from investigating square areas on the wear tracks, with the help of a proposed methodology, for initial and tested surfaces generated on the blocks and on counterpart ring made of rolling bearing steel, for the following test conditions: three normal forces (F = 1 N, F = 2.5 N and F =5 N), three sliding speeds (v = 0.25 m/s, v = 0.50 m/s and v = 0.75 m/s) and a sliding distance of L = 7500 m. The conclusion of the research study was that the tested normal force range has an insignificant influence on the surface quality for the tested materials and parameters. This friction couple could be recommended for variable conditions (speed and load) in dry regimes.

33-39

Authors: B. Bobić, A. Vencl, M. Babić, S. Mitrović, I. Bobić

The influence of corrosion on the microstructure of ZA27/SiCp composites was examined. The composites were produced by compo casting technique and then subjected to the thermal treatment (T4 regime). Microstructural examinations were performed after 30-day exposure of thermally treated composites in the sodium-chloride solution. Corrosion processes have occurred in the composite matrix. Corrosion did not affect SiC particles in the composites. The local progress of corrosion in depth of the composite matrix was noticed in micro-cracks. Corrosion resistance of ZA27/SiCp composites was evaluated based on the mass loss of composite samples during the immersion test. It was found that corrosion resistance of the composites decreased with increase in content of SiC particles. The applied thermal treatment had a negative influence on the corrosion resistance of ZA27/SiCp composites.

49-66

Authors: A. Belhocine, A.R.A. Bakar, M. Bouchetara

Safety aspect in automotive engineering has been considered as a number one priority in development of new vehicle. Each single system has been studied and developed in order to meet safety requirement. Instead of having air bag, good suspension systems, good handling and safe cornering, there is one most critical system in the vehicle which is brake systems. The objective of this work is to investigate and analyse the temperature distribution of rotor disc during braking operation using ANSYS Multiphysics. The work uses the finite element analysis techniques to predict the temperature distribution on the full and ventilated brake disc and to identify the critical temperature of the rotor by holding account certain parameters such as; the material used, the geometric design of the disc and the mode of braking. The analysis also gives us, the heat flux distribution for the two discs.

74-78

Authors: J. Kaleicheva

The microstructure and properties of austempered ductile iron (ADI) strengthened with nanosized addtives of titanium nitride + titanium carbonitride (TiN + TiCN), titanium nitride TiN and cubic boron nitride cBN are investigated. The TiN, TiCN and cBN, nanosized particles are coated by electroless nickel coating EFTTOM-NICKEL prior to the edition to the melt. The spheroidal graphite iron samples are undergoing an austempering, including heating at 900 оС for an hour, after that isothermal retention at 280 оС, 2 h and 380 оС, 2h. The metallographic analysis by optical metallographic microscope GX41 OLIMPUS and hardness measurements by Vickers Method are performed. The structure of the austempered ductile iron consists of lower bainite and upper bainite.Experimental investigation of the wear by fixed abrasive are also carried out. The influence of the nanosized additives on the microstructure, mechanical and tribological properties of the austempered ductile irons (ADI) is studied.

90-96

Authors: M. Matejić, M. Blagojević, V. Marjanović, R. Vujanac, B. Simić

Proper winding of the steel rope around the winch drum is great importance, mostly for: prolonging the service life of the rope, reduction of deformations of the body and the sides of the drum if the winding of the rope is multilayered, increasing of the safety factors, easier unwinding of the rope while lowering the load, even running of the drive unit, etc. The focus of this paper is on the analysis of the friction which occurs in the process of winding and unwinding the rope around the winch drum. Friction force is in its highest intensity when the rope passes from one layer to another, if the winding of the rope is multilayered. As the result of the research, certain mechanisms of winding of the rope from the aspects of the friction force were obtained, and the effects of the forces on the sides of the drum were analyzed.