Engineering materials lab report (Lubricating & Insulating Material)s

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Lubricating & Insulating Materials Lab Report
Engineering Materials Lab Report
Submitted to: Sir Suleiman
Nabeel Sultan (2015-CH-244)
University of Engineering and Technology, Lahore KSK Campus

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LUBRICATING MATERIAL

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Introduction
Lubrication is the process or
technique employed to reduce friction
between surfaces in proximity and moving
relative to each other, by interposing a
substance called a lubricant in between them.
The lubricant can be a solid, (e.g.
Molybdenum disulfide 𝑀𝑜𝑆2) a solid/liquid
dispersion, a liquid such as oil or water, a
liquid-liquid dispersion (a grease) or a gas.
The science of friction, lubrication and wear is called tribology.
Importance of lubrication
 Adequate lubrication allows smooth continuous operation of equipment.
 Reduces the rate of wear.
 Prevents excessive stresses or seizures at bearings.
 When lubrication breaks down, components can rub destructively against each other,
causing heat, local welding, destructive damage and failure.
 Dissolving or transporting foreign particles and distributing heat.
 Another approach is to use ball bearings, roller bearing or air bearings which in turn
require internal lubrication themselves.
 Prevent corrosion.
Lubricants Materials
Compositions of lubricants
Typically, lubricants contain 90% base oil (most often petroleum fractions, called mineral
oils) and less than 10% additives. Vegetable oils or synthetic liquids such as hydrogenated
polyolefin, esters, silicones, fluorocarbons and many others are sometimes used as base oils.

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Types of lubricants:
Types of lubricants
Solid lubricants Semi solid Liquid Lubricants Synthetic lubricants
Wax Grease Polyglycols Imines
Talc Vaseline Silicones Amides
Mica
Additives used in lubricants
 Anti-oxidant: Aromatic amines, Phenols, Sulphides and phosphates
 Corrosion Inhibitor: Amino salts and salts of sulphonic acids
 Antiwear agents: Tricresyl phosphate
 Foam inhibitors: Glycerols
Properties of lubricants:
 A good lubricant generally possesses the following characteristics:
 high boiling point and low freezing point (in order to stay liquid within a wide range of
temperature)
 High viscosity index
 Thermal stability
 Hydraulic stability
 Corrosion prevention
 High resistance to oxidation.
Selection of Lubricants:
Roller chain lubricant is applied to the outer surfaces and allowed to flow into the pin-and-
bushing joint. For this reason, coating the chain with a heavy, thick grease does little toward
supplying the joint with the lubricant it needs. Oil does the job better.
The oil grade, viscosity, and purity are
the most important factors for proper
chain lubrication. Because some grades
of oil contain additives or detergents that
may foam or leave a residue in the
chain’s joints, it is best to use non-
detergent, single- viscosity petroleum
oils selected primarily for the drive
operating temperatures, Table 1. If available, antifoam, anti-rust, and extreme-pressure additives

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in the oil are beneficial. Impure or used oil may have degraded in service and may contain
contaminants which can increase wear or damage the chain components. Therefore, this oil
should be replaced.
Methods of applying Lubricants
 Drip feed: A more continuous form of lubrication, the drip method is also adequate
for low-speed drives. Oil is supplied to the chain from a reservoir or manifold system,
typically at rate of 4 to 20 drops per minute. As shown in figure below:
 Oil bath and slinger disc systems: For moderate-speeds, the entire drive is contained in a
housing with an oil sump. A short section of the chain travels through the sump to pick
up oil, Figure 2. This method is often used in conjunction with a slinger disc which picks
up small amounts of oil from the sump and slings it onto the chain.

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 Oil stream: For high-speed applications, a pump directs lubricant under pressure onto the
chain at a high flow rate, Figure 3.
 Manually: Appropriate for drives operating at low speed (defined by Table 2), manual
methods generally involve applying oil with a brush or spout-can approximately every 8
hr depending on the drive conditions and duty cycle. Oil should be applied to the inside
of the chain loop so it won’t be thrown off by centrifugal force.

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Commonly used lubricating materials
Synthetic oils
Petroleum-derived lubricant
can also be produced using synthetic
hydrocarbons (derived ultimately
from petroleum). These include:
1. Polyalpha-olefin (PAO)
2. Synthetic esters
3. Polyalkylene glycols (PAG)
4. Phosphate esters
5. Alkylated naphthalenes (AN)
6. Silicate esters
7. Ionic fluids
8. Multiply alkylated cyclopentanes (MAC)
Solid Lubricants
PTFE: polytetrafluoroethylene (PTFE) is typically used as a coating layer on, for example,
cooking utensils to provide a non-stick surface. Its usable temperature ranges up to 350 °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.
The use of some such materials is sometimes restricted by their poor resistance to oxidation (e.g.,
molybdenum disulfide degrades above 350 °C in air, but 1100 °C in reducing environments.
Metal/alloy: Metal alloys, composites and pure metals can be used as grease additives or the
sole constituents of sliding surfaces and bearings. Cadmium and Gold are used for plating
surfaces which gives them good corrosion resistance and sliding properties, Lead, Tin, Zinc
alloys and various Bronze alloys are used as sliding bearings, or their powder can be used to
lubricate sliding surfaces alone.
Aqueous lubrication:
Aqueous lubrication is of interest in a number of technological applications. Strongly hydrated
brush polymers such as PEG can serve as lubricants at liquid solid interfaces. By continuous
rapid exchange of bound water with other free water molecules, these polymer films keep the
surfaces separated while maintaining a high ﬂuidity at the brush–brush interface at high
compressions, thus leading to a very low coefﬁcient of friction.

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Bio lubricants:
Bio lubricants are derived from vegetable oils and other renewable sources. They usually are
triglyceride esters (fats_ obtained from plants and animals. For lubricant base oil use the
vegetable derived materials are preferred. Common ones include high oleic canola oil, castor oil,
palm oil, sunflower seed oil and rapeseed oil from vegetable, and Tall oil from tree sources.
Many vegetable oils are often hydrolyzed to yield the acids which are subsequently combined
selectively to form specialist synthetic esters. Other naturally derived lubricants include lanolin
(wool grease, a natural water repellent).
Whale oil was a historically important lubricant, with some uses up to the latter part of the 20th
century as a friction modifier additive for automatic transmission fluid.

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Insulating Materials

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Introduction
Thermal insulation is the reduction of
heat transfer (the transfer of thermal energy
between objects of differing temperature)
between objects in thermal contact or in range
of radiative influence. Thermal insulation can be
achieved with specially engineered methods or
processes, as well as with suitable object shapes
and materials.
Heat flow is an inevitable consequence of
contact between objects of differing
temperature. Thermal insulation provides a
region of insulation in which thermal conduction is reduced or thermal radiation is reflected
rather than absorbed by the lower-temperature body.
The insulating capability of a material is measured with thermal conductivity (k). Low thermal
conductivity is equivalent to high insulating capability (R-value). In thermal engineering, other
important properties of insulating materials are product density (ρ) and specific heat capacity (c).
Properties of Insulating materials
Insulations are defined as those materials or combinations of materials which retard the flow of
heat energy by performing one or more of the following functions:
1. Conserve energy by reducing heat loss or gain.
2. Control surface temperatures for personnel protection and comfort.
3. Facilitate temperature control of process.
4. Prevent vapor flow and water condensation on cold surfaces.
5. Increase operating efficiency of heating/ventilating/cooling, plumbing, steam, process and
power systems found in commercial and industrial installations.
6. Prevent or reduce damage to equipment from exposure to fire or corrosive atmospheres.
7. Assist mechanical systems in meeting criteria in food and cosmetic plants.
8. Reduce emissions of pollutants to the atmosphere.
The temperature ranges within which the term "thermal insulation" will apply, is from -75°C to
815°C. All applications below -75°C are termed "cryogenic", and those above 815°C are termed
"refractory".

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Classification of thermal insulation on the basis of temperature range
LOW TEMPERATURE THERMAL INSULATION
1. From15°C through 1°C - i.e. Cold or chilled water.
2. 0°C through -40°C - i.e. Refrigeration or glycol.
3. -41°C through -75°C - i.e. Refrigeration or brine.
4. -76°C through -273°C (absolute zero) - i.e. Cryogenic. (Not addressed in this manual).
Insulating materials for this range
a. Cellular Glass
b. Elastomeric Foamed Plastic
c. Glass Fiber
d. Mineral Fiber
e. Phenolic (foamed)
f. Polyethylene
g. Polyisocyanurate
h. Polyurethane
i. Polystyrene
INTERMEDIATE TEMPERATURE THERMAL INSULATION
1. 16°C through 100°C - i.e. Hot water and steam condensate.
2. 101°C through 315°C - i.e. Steam, high temperature hot water.
Insulating materials for this range
a. Calcium Silicate
b. Cellular Glass
c. Elastomeric Foamed Plastic
d. Expanded Silica, or Perlite
e. Glass Fiber
f. Mineral Fiber
g. Phenolic

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h. Polystyrene
i. Polyurethane
HIGH TEMPERATURE THERMAL INSULATION
1. 316°C through 815°C - i.e. Turbines, breechings, stacks, exhausts, incinerators, boilers.
Insulation materials used for this range
a. Calcium Silicate
b. Cellular Glass
c. Cements
d. Ceramic Fibers
e. Glass Fibers
f. Mineral Fiber
g. Perlite
TYPES OF INSULATIONS:
 Fibrous Insulation: composed of small diameter fibers which finely divide the air space.
The fibers may be perpendicular or parallel to the surface being insulated, and they may
or may not be bonded together. Silica, rock wool, slag wool and alumina silica fibers are
used. The most widely used insulations of this type are glass fiber and mineral wool.
Glass fiber and mineral wool products usually have their fibers bonded together with
organic binders that supply the limited structural integrity of the products.
 Cellular Insulation: composed of small individual cells separated from each other. The
cellular material may be glass or foamed plastic such as polystyrene (closed cell),
polyisocyanurate and elastomeric.
 Granular Insulation: composed of small nodules which may contain voids or hollow
spaces. It is not considered a true cellular material since gas can be transferred between
the individual spaces. This type may be produced as a loose or pourable material, or
combined with a binder and fibers or undergo a chemical reaction to make a rigid
insulation. Examples of these insulations are calcium silicate, expanded vermiculite,
perlite, cellulose, diatomaceous earth and expanded polystyrene.

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FORMS OF INSULATIONS
Insulations are produced in a variety of forms suitable for specific functions and applications.
The combined form and type of insulation determine its proper method of installation. The forms
most widely used are:
 Rigid boards, blocks, sheets, and pre-formed shapes such as pipe insulation, curved
segments, lagging etc. Cellular, granular, and fibrous insulations are produced in these
forms.
 Flexible sheets and pre-formed shapes. Cellular and fibrous insulations are produced in
these forms.
 Flexible blankets. Fibrous insulations are produced in flexible blankets.
 Cements (insulating and finishing). Produced from fibrous and granular insulations and
cement, they may be of the hydraulic setting or air drying type.
 Foams. Poured or froth foam used to fill irregular areas and voids. Spray used for flat
surfaces.
MAJOR INSULATION MATERIALS
The following is a general inventory of the characteristics and properties of major insulation
materials used in commercial and industrial installations. See the Insulation Property Tables at
the end of Section 2 for a comparative review.
CALCIUM SILICATE
Calcium silicate insulation is composed principally of hydrous calcium silicate which usually
contains reinforcing fibers; it is available in molded and rigid forms. Service temperature range
covered is 35°C to 815°C. Flexural and compressive strengths is good. Calcium silicate is water
absorbent. However, it can be dried out without deterioration. The material is non-combustible
and used primarily on hot piping and surfaces. Jacketing is field applied.
MINERAL FIBER
a. Glass: Available as flexible blanket, rigid board, pipe covering and other pre-molded shapes.
Service temperature range is -40°C to 232°C. Fibrous glass is neutral; however, the binder may
have a pH factor. The product is non-combustible and has good sound absorption qualities.
b. Rock and Slag: Rock and slag fibers are bonded together with a heat resistant binder to
produce mineral fiber or wool. Upper temperature limit can reach 1035°C. The same organic
binder used in the production of glass fiber products is also used in the production of most
mineral fiber products. Mineral fiber products are non-combustible and have excellent fire
properties.
CELLULAR GLASS
Available in board and block form capable of being fabricated into pipe covering and various
shapes. Service temperature range is -273C to 200°C and to 650°C in composite systems. Good

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structural strength, poor impact resistance. Material is non-combustible, non-absorptive and
resistant to many chemicals
EXPANDED SILICA, OR PERLITE
Insulation material composed of natural or expanded perlite ore to form a cellular structure;
material has a low shrinkage coefficient and is corrosion resistant; non-combustible, it is used in
high and intermediate temperature ranges. Available in pre-formed sections and blocks.
ELASTOMERIC FOAM
Foamed resins combined with elastomers to produce a flexible cellular material. Available in
pre-formed sections or sheets, Elastomeric insulation offer water and moisture resistance. Upper
temperature limit is 105C . Product is resilient. Fire resistance should be taken in consideration.
FOAMED PLASTIC
Insulations produced from foaming plastic resins create predominately closed cellular rigid
materials. "K" values decline after initial use as the gas trapped within the cellular structure is
eventually replaced by air. Check manufacturers' data. Foamed plastics are light weight with
excellent cutting characteristics. The chemical content varies with each manufacturer. Available
in pre-formed shapes and boards, foamed plastics are generally used in the lower intermediate
and the entire low temperature ranges. Consideration should be made for fire retardancy of the
material.
REFRACTORY FIBER
Refractory Fiber insulations are mineral or ceramic fibers, including alumina and silica, bonded
with extremely high temperature inorganic binders, or a mechanical interlocking of fibers
eliminates the need for any binder. The material is manufactured in blanket or rigid form.
Thermal shock resistance is high. Temperature limits reach 1750°C. The material is non-
combustible.
The use and design of refractory range materials is an engineering art in its own right and is not
treated fully in this manual, although some refractory products can be installed using application
methods illustrated here.
INSULATING CEMENT
Insulating and finishing cements are a mixture of various insulating fibers and binders with water
and cement, to form a soft plastic mass for application on irregular surfaces. Insulation values are
moderate. Cements may be applied to high temperature surfaces. Finishing cements or one-coat
cements are used in the lower intermediate range and as a finish to other insulation applications.
Check each manufacturer for shrinkage and adhesion properties

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