Conference Paper Study of Rheological Properties of Industrial Lubricants Ajay Vasishth, 1 Piyush Kuchhal, 2 and Gagan Anand 2 1 Department of Physics, Chandigarh University, Chandigarh, Punjab 160017, India 2 Department of Physics, University of Petroleum and Energy Studies, Dehradun 248007, India Correspondence should be addressed to Gagan Anand; gagan4567@redifmail.com Received 11 February 2014; Accepted 11 March 2014; Published 14 May 2014 Academic Editors: R. K. Shivpuri and G. N. Tiwari Tis Conference Paper is based on a presentation given by Gagan Anand at “National Conference on Advances in Materials Science for Energy Applications” held from 9 January 2014 to 10 January 2014 in Dehradun, India. Copyright © 2014 Ajay Vasishth et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te most important rheological parameter for lubricants is viscosity as it also afects the tribological properties like friction between interacting surfaces and wear. Tis research intends to study the relationship between viscosity and temperature at diferent shear rates for multiple grades of three diferent categories of lubricants used for diferent applications viz. L1: MG20W50 (engine oil), L2: SAE20W50 (engine oil), L3: MC20W50 (mineral engine oil), L4: EP90 (gear oil), and L5: DXTIII (steering fuid). Constant high dynamic viscosity, shear stress, and low compressibility at diferent temperatures in multigrade as well as single grade industrial oil will help to maintain the surface flm over the period of time and hence the reduction in wear. Te dynamic viscosity of these chosen samples has been measured experimentally in temperature range of 20 to 50 ∘ C. Te measurements have been extended to observe the dependence of shear rate, time, and temperature on the dynamic viscosity. All the samples are observed to behave like Newtonian fuids in the entire temperature range of study. Further, all samples seem to obey the Arrhenius relationship with temperature. Shear stress shows linear variation with shear rate exhibiting uniform viscosity which is substantiated by almost no variation in dynamic viscosity with shear rate for value above 5 per second. 1. Introduction Te role of lubrication is an important part in the feld of tribology. Lubrication is to smoothen the movement of one surface over another and to maintain the viscoelastic behavior [1]. Lubricants are commonly used for lubrication to reduce the friction and wear of surfaces in contact [2] and efective heat transfer due to good thermal conductivity. Most lubri- cants are liquids (such as mineral oils, synthetic oil, silicon fuids, water, etc.). Selection of lubricant is very important for providing machine tools a longer life. To select an appropriate lubricant, it is necessary to know its properties, lubrication system of applied machinery, conditions of machinery, cost of lubricant [3]. Common properties of lubricating oil are: viscosity, viscosity index, density, compressibility, surface tension, cloud point, pour point or low temperature prop- erty, fash point, friction coefcient, high boiling point, low freezing point, thermal stability, corrosion prevention, high resistance to oxidation, and so forth. Te most important property is its viscosity. Viscosity is a function of temperature and pressure. Te relationship between the viscosity and temperature and the relationship between viscosities and pressure are also important in lubricant rheology as well as for the life of machine elements. Just as temperature rise reduces the viscosity of lubricating oil, also an increase in pressure produces a rise in its viscosity. Barus expressed a relation between viscosity and pressure introducing a constant  named pressure-viscosity coefcient [4]. In recent years, pres- sure viscosity relationship became an important parameter of lubricating oil to understand its performance, especially in high-temperature applications, so viscosity measurement becomes an important tool for doing so. Rheology is the study of the fow of matter: mainly liquids but also sof solids or solids under conditions in which they fow rather than deform elastically. It would be difcult to imagine any Hindawi Publishing Corporation Conference Papers in Science Volume 2014, Article ID 324615, 5 pages http://dx.doi.org/10.1155/2014/324615