Lubricant Wikipedia. A lubricant is a substance, usually organic, introduced to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity. In addition to industrial applications, lubricants are used for many other purposes. Hot Girl From Canada S Worst Driver. Other uses include cooking oils and fats in use in frying pans, in baking to prevent food sticking, bioapplications on humans e. HistoryeditLubicants have been in some use for thousands of years. Calcium soaps have been identified on the axles of chariots dated to 1. BC. Building stones were slid on oil impregrated lumber in the time of the pyramids. In the Roman era, lubricants were based on olive oil and rapeseed oil, as well as animal fats. Fundamentals Of Tribology Book Free' title='Fundamentals Of Tribology Book Free' />The growth of lubrication accelerated in the Industrial Revolution with the accompanying use of metal based machinery. Relying initially on natural oils, needs for such machinery shifted toward petroleum based materials early in the 1. A breakthrough came with the development of vacuum distillation of petroleum, as described by the Vacuum Oil Company. This technology allowed the purification of very nonvolatile substances, which are common in many lubricants. PropertieseditA good lubricant generally possesses the following characteristics A high boiling point and low freezing point in order to stay liquid within a wide range of temperatureA high viscosity index. Thermal stability. TEXTBOOK GCSE PHYSICS OCR GATEWAY ANSWERS FOR WORKBOOK PDF EBOOKS architecture foundation keegan edward universe2008 paperback. Hydraulic stability. Demulsibility. Corrosion prevention. Fundamentals Of Tribology Book Free' title='Fundamentals Of Tribology Book Free' />A high resistance to oxidation. FormulationeditTypically lubricants contain 9. Vegetable oils or synthetic liquids such as hydrogenated polyolefins, esters, silicones, fluorocarbons and many others are sometimes used as base oils. Additives deliver reduced friction and wear, increased viscosity, improved viscosity index, resistance to corrosion and oxidation, aging or contamination, etc. Non liquid lubricants include powders dry graphite, PTFE, molybdenum disulphide, tungsten disulphide, etc., PTFE tape used in plumbing, air cushion and others. History of Materials in the ASME Boiler and Pressure Vessel Code 3. Basis for Acceptance of Materials for Code Construction Section II, Part A Ferrous. If looking for the book Vehicle Noise and Vibration Refinement Woodhead Publishing in Mechanical Engineering in pdf form, then youve come to loyal. Since 1995 The HERRING GROUP Inc has specialized in heat treat consulting industrial education, technical writing and help solving industrial Heat Treating problems. Tribology in Engineering by Hasim Pihtili ed. EBooks Directory. You can download the book or read it online. It is made freely available by its. Mechanical Engineering books at EBooks Directory documents with free access on the Internet. These books are made freely available by their respective authors and. Dry lubricants such as graphite, molybdenum disulphide and tungsten disulphide also offer lubrication at temperatures up to 3. C higher than liquid and oil based lubricants are able to operate. Limited interest has been shown in low friction properties of compacted oxide glaze layers formed at several hundred degrees Celsius in metallic sliding systems, however, practical use is still many years away due to their physically unstable nature. AdditiveseditA large number of additives are used to impart performance characteristics to the lubricants. Modern automotive lubricants contain as many as ten additives, comprising up to 2. Pour point depressants are compounds that prevent crystallization of waxes. Long chain alkylbenzenes adhere to small crystallites of wax, preventing crystal growth. Anti foaming agents are typically silicone compounds which lower surface tension in order to discourage foam formation. Despicable Me 2 Full Movie In Hindi Free Download In Hd. Virtual Villagers 5 Full Version. Viscosity index improvers VIIs are compounds that allow lubricants to remain viscous at higher temperatures. Typical VIIs are polyacrylates and butadiene. Antioxidants suppress the rate of oxidative degradation of the hydrocarbon molecules within the lubricant. At low temperatures, free radical inhibitors such as hindered phenols are used, e. At temperatures 9. C, where the metals catalyze the oxidation process, dithiophosphates are more useful. In the latter application the additives are called metal deactivators. Detergents ensure the cleanliness of engine components by preventing the formation of deposits on contact surfaces at high temperatures. Corrosion inhibitors rust inhibitors are usually alkaline materials, such as alkylsulfonate salts, that absorb acids that would corrode metal parts. Anti wear additives form protective tribofilms on metal parts, suppressing wear. They come in two classes depending on the strength with which they bind to the surface. Popular examples include phosphate esters and zinc dithiophosphates. Extreme pressure anti scuffing additives form protective films on sliding metal parts. Design for lifetime performance and reliability Advanced engineering design Lifetime performance and reliability This book contains 472 pages in fullcolorand over. These agents are often sulfur compounds, such as dithiophosphates. Friction modifiers reduce friction and wear, particularly in the boundary lubrication regime where surfaces come into direct contact. Types of lubricantseditIn 1. Automotive applications dominate, but other industrial, marine, and metal working applications are also big consumers of lubricants. Although air and other gas based lubricants are known e. Lubricants are generally composed of a majority of base oil plus a variety of additives to impart desirable characteristics. Although generally lubricants are based on one type of base oil, mixtures of the base oils also are used to meet performance requirements. Base oil groupseditMineral oil term is used to encompass lubricating base oil derived from crude oil. The American Petroleum Institute API designates several types of lubricant base oil 5Manufactured by solvent extraction, solvent or catalytic dewaxing, and hydro finishing processes. Common Group I base oil are 1. SN solvent neutral, 5. SN, and 1. 50. BS brightstockGroup II Saturates 9. SAE viscosity index of 8. Manufactured by hydrocracking and solvent or catalytic dewaxing processes. Group II base oil has superior anti oxidation properties since virtually all hydrocarbon molecules are saturated. It has water white color. Group III Saturates 9. SAE viscosity index over 1. Manufactured by special processes such as isohydromerization. Can be manufactured from base oil or slax wax from dewaxing process. Group IV 3 b Polyalphaolefins PAOGroup V All others not included above such as naphthenics, PAG, l 8. The lubricant industry commonly extends this group terminology to include Group I with a viscosity index of 1. Group II with a viscosity index of 1. Group III with a viscosity index of at least 1. Can also be classified into three categories depending on the prevailing compositions Paraffinic. Naphthenic. Aromatic. Lubricants for internal combustion engines contain additives to reduce oxidation and improve lubrication. The main constituent of such lubricant product is called the base oil, base stock. While it is advantageous to have a high grade base oil in a lubricant, proper selection of the lubricant additives is equally as important. Thus some poorly selected formulation of PAO lubricant may not last as long as more expensive formulation of Group III lubricant. Synthetic oilseditPetroleum derived lubricant can also be produced using synthetic hydrocarbons derived ultimately from petroleum. These include Solid lubricantseditPTFE polytetrafluoroethylene PTFE is typically used as a coating layer on, for example, cooking utensils to provide a non stick surface. Its usable temperature range up to 3. C and chemical inertness make it a useful additive in special greases. Under extreme pressures, PTFE powder or solids is of little value as it is soft and flows away from the area of contact. Ceramic or metal or alloy lubricants must be used then. Inorganic solids Graphite, hexagonal boron nitride, molybdenum disulfide and tungsten disulfide are examples of solid lubricants. Some retain their lubricity to very high temperatures.