International Conference on Mechanical, Industrial and Materials Engineering 2013 (ICMIME2013) 1-3 November, 2013, RUET, Rajshahi, Bangladesh.

Paper ID: AB-000

Tribological Research and Industrial Applications in Bangladesh

Sobahan Mia*1, Md. Mahamudur Rahman1, Dipayan Mondal1, Muhsia Tabassum1 1

Dept. of Mechanical Engineering, Khulna University of Engineerint & Technology

Khulna, Bangladesh. E-mail: [email protected]

Abstract Tribology is the science and technology of interacting surfaces in relative motion and of related subjects and practices. Industries and their productions are most important in a country’s economy. Industrial machineries are the life of an industry for their production but friction and wear is the main enemy of the machineries as it is the cause of mechanical failure and hampers the production. Tribological practice is necessary in the industry to increase the production as well as the GDP in a country. In this study tribological investigation has been done on research and industrial applications in Bangladesh. Different types of gear mechanisms, bearing, conveyors, roller mechanisms and workshop machineries have been found. Maintenance departments of respective industry usually maintain machineries on daily, weekly, monthly or as required basis. Greases and Mineral oils are mainly used as lubricant in different gear mechanisms. Investigation has found that most of the industries do not use the lubricant according to standard with respect to the application. In case of large gears, extreme pressure lubricating oil is essential and also now a days synthetic oil have sufficiently good properties to improve the life of machineries. So practicing the tribology in industrial sector may leads to great plant efficiency, better performance, fewer breakdowns and significant savings. Collaboration of research and industrial application is necessary for the improvement the performance and life of machineries in Bangladesh. Keywords: Tribology, Friction, Wear, Lubrication.

1. Introduction The word tribology was first reported in a landmark report by Jost [1] in 1966. The word is derived from the Greek word tribos meaning rubbing, so the literal translation would be “the science of rubbing”. Its popular English language equivalent is friction and wear or lubrication science, alternatively used. The latter term is hardly all inclusive. Dictionaries define tribology as the science and technology of interacting surfaces in relative motion and of related subjects and practices. Tribology is the art of applying operational analysis to problems of great economic significance, namely, reliability, maintenance, and wear of technical equipment, ranging from spacecraft to household appliances. Surface interactions in a tribological interface are highly complex, and their understanding requires knowledge of various disciplines including physics, chemistry, applied mathematics, solid mechanics, fluid mechanics, thermodynamics, heat transfer, materials science, rheology, lubrication, machine design, performance and reliability. Historically, Leonardo da Vinci (1452–1519) was the first to enunciate two laws of friction. According to da Vinci, the frictional resistance was the same for two different objects of the same weight but making contacts over different widths and lengths. He also observed that the force needed to overcome friction is doubled when the weight is doubled. Similar observations were made by Charles-Augustin de Coulomb (1736–1806).

2. Industrial Significance of Tribology Tribology is crucial to modern machinery which uses sliding and rolling surfaces. Examples of productive friction are brakes, clutches, driving wheels on trains and automobiles, bolts, and nuts. Examples of productive wear are writing with a pencil, machining, polishing, and shaving. Examples of unproductive friction and wear are internal combustion and aircraft engines, gears, cams, bearings, and seals. According to some estimates, losses resulting from ignorance of tribology amount in the United States to about 6% of its gross national product (or about $200 billion dollars per year in 1966)[2], and approximately one-third of the world's energy resources in present use appear as friction in one form or another. Thus, the importance of friction reduction and wear control cannot be overemphasized for economic reasons and long-term reliability. According to Jost (1966, 1976), the United Kingdom could save approximately 500 million pounds per annum, and the United States could save in excess of 16 billion dollars per annum by better tribological practices. The savings are both substantial and significant, and these savings can be obtained without the deployment of large capital

investment. Tribology plays an important role in manufacturing. In metal-forming operations, friction increases tool wear and the power required to work a piece. This results in increased costs due to more frequent tool replacement, loss of tolerance as tool dimensions shift, and greater forces are required a piece. A layer of lubricant which eliminates surface contact virtually eliminates tool wear and decreases needed power by one third. In Bangladesh, there is a vast significance of tribology in various industries. Various machineries are present in the industry where friction and wear of the machine parts are mostly important. Here the research in tribology is needed for the minimization and elimination of losses resulting from friction and wear at all levels of technology where the rubbing of surfaces is involved. It may be noticed that research in tribology leads to greater plant efficiency, better performance, fewer breakdowns, significant savings and consequently an increased GDP of our country.

Fig 1. Practical objectives of Tribology

3. Research and Development of Tribology Research on tribology included the development of lubrication and lubricant properties, friction and wear behavior of different materials and its development. Perhaps as much as one third of our global energy consumption is consumed wastefully in friction; at a time, when energy resources are at a premium the contribution that can be made to their efficient utilization, as well as to the reduction of pollution, by making use of the tribological practices is obvious. In addition to this primary saving of energy there are very significant additional economies to be made by reductions in the cost involved in the manufacture and replacement of prematurely worn components. This study has been conducted on tribological investigation of industrial machineries in Bangladesh. Tribological practice in Bangladesh is not very well known but it is well known area in developed countries also in India. India already formed a society of tribologist in India and doing research to improve the machine and machineries life. Bishas [3] reviewed the current research and development of tribology in India. There are many organization in different countries related to tribology such as Society of Tribologist and Lubrication Engineers (STLE), Japan Society of Tribologist (JAST), Australian Society of Tribologist (AUSTRIB). The types of industries involved in tribological development are Steel; rolling mills, Nuclear energy, Thermal power, Aircraft, Cement, Oil & Grease, Machine tools; cutting oil, Automobile and Oil & testing and lubrication system. Researcher [4] found that in fluid film lubrication, the effects of surface irregularities on the lubricating performance and increase in friction in high speed bearings due to turbulent flow are highlighted to date. Elastohydrodynamic lubrication and its related problems such as traction play an important role in the lubrication of cams and followers, rolling contact bearings and traction drives. The rheology of lubricants at

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high pressures is one of the most important properties governing lubricated concentrated contacts. Regarding basic studies on wear, the mechanism of the adhesive wear process is being studied. The chemical reactions of lubricating oil additives with frictional surfaces play important roles in lubricated concentrated contacts. Recently there have been many studies on the correlation between the lubricating properties and the chemical reactivity of lubricant additives. Now a day tribological researches are going on every industries in Japan. Idemitsu Oil Company, Japan Energy, etc Oil manufacturing companies introducing new oils for the specific applications. They are also extended their research in Space tribology and Bio-tribology. China and Korea also developed their industries by improving tribological applications and practice in industries and tribological education [5,6]. Large technology development programs were carried out in Finland to integrate the tribological knowledge into condition monitoring, diagnostic and prognostic methods for improvement of industrial reliability and availability. The Finnish industry has all the time been actively involved in all these tribological activities. The steel companies Rautaruukki & Imatra Steel have developed new products and used tribological knowledge for the development of new wear resistant materials such as Kymenite, a new wear resistant spherical graphite cast iron for components, and M-steel for improved machinability.

4. Tribology in Bangladesh There are many industries such as steel re-rolling industry, cement industry, jute industry, paper industry etc are important in the economy in Bangladesh. Few industries were visited for this study and observed the tribological application. All the machineries and their lubrication system of the industries were investigated. Especially lubricants system was properly investigated where friction and wear are involved. Various lubricants are used in these industries for the minimization and elimination of losses resulting from friction and wear at all levels of technology where the rubbing of surfaces is involved. In the jute mill industry, most commonly lubricant Energol CS-150, 30 (A range of high quality, solvent refined, non-additive oils which possess inherently high resistance to oxidation and emulsification, and therefore offer long service life with minimum deterioration of properties during use) is used in reduction gears, plain bearings and also as machine oils. Advantages of this lubricant are Good natural oxidation stability for long service life, Good demulsibility, the highest viscosity index, Low pour point, enabling the oil to flow readily at low temperatures, thus minimizing the risk of overloading electric motors and switchgear, ensuring rapid flow to all parts of the system at startup. However Grease (a high performance, highly water resistant, extreme pressure, lithium soap grease) is used for medium speed bearings, pins, universal joints. In the cement industry, common lubricants are used such as Mobilgear SHC XMP Series, Mobilith SHC 1500, Mobilgear SHC 22M/46M for the machineries Crushers (Jaw Type), Slurry Basins / Wash Mills, Conveyors, Drive, Exhaust Fan for motor, bearings, gear boxes, pivots etc. The advantages wear protection, high load capability, wide operating temperature range, extended lubrication interval are the common. But in our investigation the lubricants generally used for all machineries are SP-100 (Mineral Extreme Pressure (EP) gear oil, ISO VG 100), 220 (Mineral Extreme Pressure (EP) gear oil, ISO VG 220), 320 (Mineral Extreme Pressure (EP) gear oil, ISO VG 320), 460 (Mineral Extreme Pressure (EP) gear oil, ISO VG 460). These lubricants are formulated for heavy duty applications. It is found from our investigation that, each industry has a systematic maintenance schedule in its hand, but in some cases they fail to maintain that schedule properly. In some cases, a lubricant is used for more than one time without refining it or mixing proper additives with it. These may cause break down of machineries, or the life cycle of a machine may deemed out. No industry can provide documents about the failure rate or wear rate of machineries and the cause of these occurrences. But frequently they face the wearing out or breaking down of machinery parts. But in most cases these failures do not go under any kind of investigation. They simply keep out the damaged parts, machining it and use it again. Engine tribology is another important field of tribology. Tribology is a key contributor to these efforts through the control of frictional energy losses, wear and oil consumption. The automobile consists of many hundreds of tribological components, from bearings, pistons, transmissions, clutches, gears, to wiper blades, tyres, and electrical contacts, many of which rely on the interaction of their surfaces to function. Reduction of sulphur, phosphorous, CO, CO2 and NOx in exhaust emissions has been the priority of automobile manufacturers without compromising the desired tribological performance. In general, a reduction in noxious exhaust emissions from automobiles can be achieved through tribology either by developing new engine oils that reduce friction and have low or no sulphur, phosphorous and ash containing additives and/or by developing new surface materials (alloys/coatings) that are less dependent on sulphur and phosphorous containing engine oils. The application of tribological principles is essential for the reliability of the vehicle, and even the smallest improvements in engine efficiency, emission levels, and durability can have a major effect on the world economy and the environment in the medium to long term given the huge size of the global vehicle population.

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Automobile and oil manufacturers are under increasing pressure from consumers and competitors to design efficient engines capable of running on environmentally friendly engine oils. Increasing demand for improved fuel economy and environmental protection has meant that there has been increased focus on the use of novel non-ferrous surface materials and coatings which have excellent tribological properties. As engine lubricants have historically been formulated for ferrous materials and react chemically with the surface, it is highly unlikely that they will perform well on alternative surfaces. It is therefore crucial to understand how the existing lubricants interact with non-ferrous coatings to be able to sensibly approach the design of new additives for such surfaces. Priest and Taylor [7] expressed their result for automobile engine tribology and typical tribological performance parameter is shown in Table 1. Table 1 : Typical tribological and performance parameter for a gasoline engine [7] Parameter

Engine bearing

Minimum lubricant film thickness Maximum temperature Maximum pressure/specific loading Maximum shear rate Power loss (typical) Minimum dymanic viscosity Composite surface roughness

< 1m 180C 60 MPa 108 s-1 0.25 kW 0.0025 Pa.s 0.35 m Ra

Piston ring/ liner compression ring) <0.2 m 200C groove, 120C liner 70 MPa 107 s-1 0.15 kW 0.0065 Pas 0.2 m Ra

(top

Cam/follower (nose) 0.1 m 150C 600 MPa 107 s-1 0.04 kW EHL 0.3 m Ra

A piston ring tribology model incorporating prediction of the change in ring face profile with wear in the engine has recently been reported by Priest et al.[8]. It assumes that the wear of the ring profile may be described by the Archard wear equation, in the form proposed by Lancaster [9]. V = kWx where, V = worn volume (m3), k = wear factor (m3 m-1 N-1), W =load (N) and x = sliding distance (m) The wear factor k is a function of the interacting materials, their surface topography, the lubricant and the operating conditions. Bangladesh can save a lots of money by using proper lubricant for different engines.

5. Conclusion Over the years, the subject of tribology came to be recognized as a very important aspect in all industrial operations. The application of correct tribological practices can protect and enhance the life of plants and machinery, improves efficiency of operations, reduce energy consumption and prevent expensive breakdowns. We see that tribology can be an important factor that can play a significant role in promoting major industries in Bangladesh. Different types of gear mechanisms, bearing, conveyors, roller mechanisms and workshop machineries have been found. The lubrication systems and type of lubricants used in the machineries have also been investigated. Maintenance departments of respective industry usually maintain machineries on daily, weekly, monthly or as required basis. Greases and Mineral oils are mainly used as lubricant in different gear mechanisms. The application of correct tribology practices can protect and enhance the life of plants and machines improves efficiency of operations, reduces energy consumption and prevents expensive breakdowns. So practicing the tribology in industrial sector and automobile engines may leads to great plant efficiency, better performance, fewer breakdowns and significant savings.

6. References [1] Jost, P., Lubrication (tribology): A Report on the Present Position and Industry's Needs, Dept. of Education and Science, HMSO, London, 1966. [2] Bhushan, B., Principles and Applications of Tribology, John Wiley and Sons, Canada, 1999 [3] Sakurai, T., Recent research on tribology in Japan, Journal of Wear, Vol. 100, No. 1-3, pp. 543-560, 1984. [4] Bishas, SK, Research & Development in Tribology in India, Tribology Online, Vol. 2, No.1, 2007. [5] Qunji Xue, Yongzhen Zhang,jian Li, Development of industrial tribology in China, Tribology online Vol. 2, No. 1, pp.10-13, 2007. [6] Dae-Eun Kim, Industrial Tribology in Korea: Past, Present & Near Future, Tribology online, Vol. 2, No.1, pp. 5-9, 2007. [7] Priest, M. and Taylor, C.M., Automobile engine tribology – approaching the surface, Wear, Vol. 241, pp. 193-203, 2000. [8] M. Priest, D. Dowson, C.M. Taylor, Predictive wear modelling of lubricated piston rings in a diesel engine, Wear Vol. 231, pp 89–101, 1999. [9] J.K. Lancaster, Dry bearings: a survey of materials and factors affecting their performance, Tribology, Vol. 12 (December), pp. 219–251, 1973.

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