Engineering materials new

Workshop Processes Engineering Materials

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PROPERTIES OF MATERIALS

What do you think the phrase

“a materials properties”

means?

“A MATERIALS INDIVIDUAL CHARACTERISTICS”

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MATERIAL PROPERTIES Mechanical Properties Electromagnetic

Properties Chemical and

Durability Properties Classification of

Materials Ferrous Materials Non Ferrous Materials

Non Metallic Thermoplastics Thermosetting Plastics Organic Materials Smart Materials Symbols/Abbreviations Forms of Supply Identification Coding

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This is the property of a metal, which enables the work to withstand a stretching load without breaking

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TENSILE STRENGTH

The ultimate Tensile Strength (UTS) of a material is the maximum load that each unit of a cross sectional area can carry before it fails. We call this the tensile stress at failure.

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TENSILE STRENGTH

This is greatly defined as the ability of a metal to resist indentation or abrasion. The measurement of hardness is usually based on a metals resistance to the indentation of either a hardened steel ball or a diamond.

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HARDNESS

MALLEABILITY A material is considered Malleable when it can be easily pressed or forged into shape. Most metals have a greater malleability when worked in the hot condition. Rivets used in engineering have to be Malleable so that they can be formed.

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DUCTILEThis term implies that a metal has the ability to be drawn into rod or wire. The ductility of a metal is determined by the amount it will stretch lengthways before it becomes brittle and fails. Because ductility reduces as the temperature of the metal is increased, metals are usually drawn in the cold state.

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BRITTLENESS

This is the opposite of plasticity. It refers to the tendency of metal to break suddenly when under load without any prior warnings. Many metals in their cast state will fracture when subjected to a large enough impact. In some metals an increase in temperature can reduce brittleness, while in others it can be caused to occur.

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This is the ability of a metal to withstand loads, which are not in the same line of force.

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SHEAR STRENGTH

COMPRESSIVE STRENGTH

This is the property that enables a metal to withstand compressive loading without fracture

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PLASTICITY

This measures the ability of a metal to be formed into a given shape without fracture. As very few metals are plastic in cold form state heat is used in most cases to increase plasticity

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ELECTRICAL CONDUCTIVITY

This is the ease with which a material conducts electricity. The most common material used for this is copper. Copper has a high electrical conductivity which allows current to flow, it is also cheaper than gold which also has a very high EC.

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This is the ability of a material to withstand an electrical current. Plastics have a very low EC and a high EI which will not allow a current to flow. This is why plastics can be used as a good insulator

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ELECTRICAL INSULATION

FERROMAGNETISM

Any metal that contains large amounts of Iron, Nickel or Colbalt can be made magnetic. Metals that contain these elements can be made to make permanent and electromagnets

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If you heat a magnet to approximately 800°C the metals magnetism will disappear. This point is known as the CURIE TEMPERATURE Of the material

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FERROMAGNETISM

This is the ability of a material to resist chemical attack

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CORROSION RESISTANCE

SOLVENT RESISTANCESome rubbers and plastics are attacked by certain chemicals. These chemicals are called solvents. Materials that are not effected by solvents are said to have a High Solvent Resistence

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If we are designing equipment that may use Petrol, Diesel or certain lubricating oils in its operation. We have to ensure that we chose materials that may contact these substances that have a HIGH SOLVENT RESISTANCE

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SOLVENT RESISTANCE

ENVIRONMENTAL DEGRADATION

If we leave certain materials out in the elements they will degrade.

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Wood will rot if exposed to moisture. Some plastics will turn brittle if exposed to UV light. Certain Rubbers will also degrade when exposed to UV light.We can overcome this by choosing the correct materials or protecting the materials we select for various applications

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We can protect wood by painting or varnishing it before use.If we are using plastic for guttering, we could use one colored black as black plastic tends to stay more flexible for longer.

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If the application requires metals to be used we can protect them from corrosion by using jointing compounds between mating surfaces, or we could clad the metal in another metal so that it acts as a barrier (Galvanized Zinc Plating). Or we could just simply paint the surface of the metal

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WEAR RESISTANCE

As we know hardness is a property of Wear Resistance. However Wear Resistance can also be looked at as the durability of the property. Machine components that come into contact with each other need to have high Wear Resistance.

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WEAR RESISTANCE

Examples of components that require high Wear Resistance are:

Bearing Surfaces Gear Teeth Sealing/Forming plates Guillotine Blades

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CLASSIFICATION OF MATERIALS

Materials used in engineering are divided into 3 main groupsThese groups depend upon the properties which the materials have.The 3 classifications are:

Ferrous materialsNon-ferrous materialsNon-metallic materials

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Iron is the main constituent of FERROUS MATERIALS. They are called Ferrous as the Latin for iron is “Ferrum”

In its purest form Iron is a soft grey metal that has poor casting properties when molten and it will not give a good surface finish when machined.

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FERROUS MATERIALS

To overcome this and improve its properties we add small amounts of Carbon, this also gives us a wide range of Cast Irons and SteelsExamples are:

Cast ironLow carbon steelMedium carbon steelHigh carbon steelAlloy steel (stainless steel, high speed steel)

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FERROUS MATERIALS

Cast iron contains between 2-4% carbon

This means that it can be poured into complicated shapes easily when molten

The Carbon in Cast Iron is in the form of Graphite, this Graphite also makes the material easier to machine, when 2 pieces of Cast Iron rub together this Graphite acts as a lubricant. Because of this we can say that Cast Iron is self lubricating

Cast contains large voids in its make-up which adds to its brittleness (excess carbon)

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CAST IRON

Cast Iron does have a disadvantage, unless it is specially treated (ANNEALED developed in France in the 18th century) to make it more malleable. It is brittle and therefore should not be subjected to high tensile loading. It is however good at withstanding compressive loading

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CAST IRON

It is made by reducing iron ore in a blast furnace. The liquid iron is cast, or poured and hardened, into crude ingots called pigs, and the pigs are subsequently re-melted along with scrap and alloying elements in cupola furnaces and recast into molds for producing a variety of products.

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CAST IRON

Examples of uses are: Machine Beds Surface Tables/Angle Plates Extreme compression components Housings Crank Shafts/Cases Frames

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CAST IRON

STEEL

Steel is one of the most common ferrous metalsIt is available in many different forms and can be ordered in two different forms:

Black or

BrightSteel is dull grey in appearance until machined or treated

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Black Steel

Black steel is the cheaper of the twoIt has a black scaly surface that needs to be machined

Bright Steel

Bright steel is more expensiveIt is possible to leave the outer surface un-machined

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STEEL

PLAIN CARBON-STEEL

There are 3 main different varieties of steel and they are determined by the amount of iron and carbon present in each. They are:

Low-carbon steelMedium-carbon steelHigh-carbon steel

By adding different amounts of carbon to steel we can change its properties they are then called Plain Carbon-steel

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LOW CARBON STEEL

More commonly known as “mild steel”

It contains between 0.1% - 0.3% carbon

It has good Tensile Strength

It has a fair degree of malleability and ductility when cold worked

When heated to a bright red colour (1490°F 810°C it becomes more malleable and ductile which means it can be pressed or rolled easily into shape

It is cheap which makes it deal for low level engineering

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Mild Steel is one of the most widely used materials in engineering. Examples of its uses are:

Girders Ships Hulls Gates and Railings Pipes General Workshop purposes

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LOW CARBON STEEL

Contains between 0.3% - 0.8% carbon

Tougher and stronger than low-carbon steel, making them hard to cut or form

The higher carbon content means that it can be heat treated (using hardening and tempering) to gain improved properties

This make them more expensive

They are difficult to work in a cold state and could crack.

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MEDIUM CARBON STEEL

Properties: Strong Can be hardened by heat

treatment.

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MEDIUM CARBON STEEL

Examples of use are: Hammers Chisels Punches Gears/Couplings Components that require a high

degree of wear and impact resistance.

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MEDIUM CARBON STEEL

HIGH CARBON STEEL

High-carbon steels are the hardest steels and the most expensive to produce but they are less ductile

Contains between 0.8% - 1.4% carbon

They respond well to heat treatment.

Very poor at cold working and fracture easily in this state

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Properties: Strong Can be made very hard by heat

treatment

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HIGH CARBON STEEL

Examples of use are:Wood Cutting ChiselsFilesTaps and DiesCraft Knives

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HIGH CARBON STEEL

STAINLESS STEEL

In addition to the iron and carbon in steels, Stainless Steel has Chromium and Nickel in its make-up. It is part of the Ferrous Metal groups called ALLOY STEELS. The extra added constituents mean that Stainless Steel is more corrosion resistant than other Steels

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Properties: Corrosion Resistant. Strong

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STAINLESS STEEL

Examples of use are: Food Preparation Counters Medical Applications Pharmaceutical Applications Cutlery Automotive Trim

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STAINLESS STEEL

NON-FERROUS MATERIALS

Non-Ferrous materials DO NOT CONTAIN IRON

Examples are:

Aluminium

Copper

Brass

Tin

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ALUMINIUM

Aluminium is the most common non-ferrous material.

Aluminium is light grey in appearance, unless it has been treated or made into an alloy, silvery when polished.

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Properties:

Light weight

Good conductivity

Corrosion resistance

Malleable

High weight to strength ratio

In its natural state is weak and ductile

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ALUMINIUM

Examples of uses are: Cylinder Heads Small Machine parts Tools Utensils Castings/Housings

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ALUMINIUM

Copper Aluminum Alloy with only a 5-10% Aluminum content.

Strong Fluid when molten

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ALUMINIUM BRONZE

Examples of uses are: Boiler and Condenser components

in heating systems Chemical plant componnets Boat Propellers

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ALUMINIUM BRONZE

As Aluminum use has grown there has been a wide range of Aluminum Alloys developed. By adding small amounts Silicon, Copper, Magnesium and Manganese you can greatly increase the strength of Aluminum. Within Aviation the most widley used Aluminum Alloy is DURALUMIN. This 4% Copper and 1% Magnesium added to it

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ALUMINIUM ALLOYS

Properties: Ductile Malleable Good Strength Good Fluidity when molten

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ALUMINIUM ALLOYS

Examples of uses: Electrical powerlines Ladders Aircraft and Motor Vehicle

components Light sand and Die Casting

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ALUMINIUM ALLOYS

LEAD

Lead is a heavy grey metal that is very malleable, it has a low tensile strength but it is highly resistant to corrosion and chemical attack. It conducts both heat and electricity with ease.

When mixed with Tin it produces a range of alloys known as SOFT SOLDERS

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Properties: Extremely soft. Heavy Low tensile strength Highly resistant to corrosion Malleable

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LEAD

Examples of uses are: Roofing. Chemical Tank liners. Balance Weights. Jointing Compounds for electrical

joints.

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LEAD

COPPER

Copper has excellent conductivity

Lightweight & very malleable

Corrosion Resistant

Excellent conductor of heat and electricity

Average Tensile Strength (this can be improved by alloying with other metals)

Copper is the main ingredient in many alloys, such as brass

In its natural state it is orangey-red appearance

Polishes well and easily joined

More costly than Aluminium.

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Examples of use are: Cooking Utensils Water Pipes Electric Cables/Wires.

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COPPER

TIN

Tin is soft and malleable Highly corrosion resistant

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Examples of use are: Tin Cans Protective coating for Mild Steel this

is known as TINPLATE Used in the production of some

solders Used with Copper to produce

Bronzes

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TIN

ZINC

Zinc is a soft brittle metal It is highly corrosion resistant. When used to “coat” other metals

it has a feathery appearance

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ZINC

Examples of uses are: Acting as a protective coating for

Mild Steel (this is then said to be Galvanized)

Building Materials Buckets/Waste Bins

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STANDARD BRASS

Standard Brass is made up of 65% copper & 35% Zinc

Cheaper than most other brass alloys

Standard brass is gold/yellow in appearance

The High Copper content means that Brass is very Ductile

The High Zinc content means that it is more fluid when molten making it suitable for casting

It is only possible to harden brass alloy through cold working (work hardening).

Heating softens the brass (the annealing processes) 69

Examples of uses: Tubes Cartridge Cases Castings

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STANDARD BRASS

Bronze is an alloy of Copper an Tin the amounts of each vary from 96% Copper and 4% Tin to 78% Copper to 22% Tin

The high Copper content means that it is malleable, ductile and elastic when forming when cold.

The high Tin content means that it is more fluid when molten allowing it to pour easily

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BRONZE

Examples of uses are: High Copper content

Electrical contactsInstrument Parts

High Tin contentPump and Valve components

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BRONZE

NON-METALLIC MATERIALS

Non-Metallic materials contain NO METALS

Examples are:

Wood

Thermosetting plastics

Thermoplastics

Rubber

Ceramics

Glass

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PLASTICS

There are many different types available. They all fall into 1 of 2 different categories

Thermosetting plastics

Thermoplastics

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THERMOPLASTICS Thermoplastics do not undergo a chemical change when heated, this means they can be reheated and re-softened over and over again

These plastics are not as hard as thermosetting plastics but they do resist impact better and are tougher

Used for tubing, film, cable insulation

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Polychloroethene AKA Poly Vinyl Chloride (PVC).

PVC is a very good material, It can be made hard or soft and it can be used in a variety of ways dependent on its application.

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THERMOPLASTICS

PVC This material can be made solvent

resistant for use in manufacturing When made hard and tough it can

be used in the manufacture of window frames, guttering and drain pipes

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THERMOPLASTICS

PVC When soft it will age harden over

time. Used as cable and wire insulation, or as upholstery. Both types can be coloured to suit the use they are intended for.

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THERMOPLASTICS

Polyamide (AKA Nylon) Nylon has a multitude of uses. It is

a tough strong flexible material that is solvent resistant. The downside to this material is that is absorbs water and it will deteriorate when exposed to the elements

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THERMOPLASTICS

Examples of uses are: Bearings Gears Cams Brush Bristles Textiles

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THERMOPLASTICS

Methyl-2 methylpropenoate (AKA Perspex)

A strong rigid transparent material that is easily scratched, a material that is not resistant to petrol based solvent attack.Perspex can be easily softened and moulded into complex forms

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THERMOPLASTICS

Examples of uses are: Aircraft Canopies Aircraft transparencies Lenses Corrugated Roofing lights Machine guards

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THERMOPLASTICS

Polytetroflouroethane (AKA PTFE or Teflon)This material has a very smooth surface with a low coefficient of friction which means it is excellent bearing material.

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THERMOPLASTICS

Properties of PTFE Teflon. Tough Flexible Heat Resistant Solvent Resistant Low coefficient of friction

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THERMOPLASTICS

Examples of uses are: Bearings Seals and Gaskets in hydraulic

systems Tape Non stick coatings

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THERMOPLASTICS

Thermosetting plastics or thermo-sets as they are sometimes known start life as either a liquid OR a powder. They sometimes have fillers added to the mixture to improve the mechanical properties of the material. They are molded into shape using heat and pressure. It is whilst this process is happening that they undergo a chemical change.

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THERMOSETTING PLASTICS

The polymers within the material become cross-linked together once they are formed they cannot be broken.

This means that once we have shaped the Thermo-set we cann6t change it

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THERMOSETTING PLASTICS Thermosetting plastics do undergo a chemical change when they are heated, and once this change takes place the plastic can never again be softened.

This means thermosetting plastics tend to be hard and brittle

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They are used mainly when heat is going to be present during operation.

Mainly used in resin base (Epoxy Resins) plastics like glass enforced plastic (fibre-glass), and for mouldings

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Phenolic Resin (AKA Bakelite) Not that commonly used anymore

this was one of the first Thermo-sets. It has limited decorative value as its colors are limited to either brown or black

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Properties of Bakelite: Hard Solvent resistant Good electrical insulator Machinable

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Examples of uses are: Electrical fittings Electrical components Insulated handles Old radio outercases

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Urea methanol resin (AKA Formica) This is very similar to Bakelite

however it is naturally transparent

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Properties of Formica are: Can be coloured Hard Solvent resistant Good electrical insulator

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Examples of uses of Formica are: Electrical fittings Kitchen fittings Bathroom fittings Kitchen hardware Laminates

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Methanal- Melamine resin (AKA Melamine)

Again this material has similar properties to both Bakelite and Formica, however when moulded this material has a smooth finish

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Properties of Melamine Harder than both Bakelite and

Formica More heat resistant than both

Bakelite and Formica Can be moulded and machined

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Examples of uses are: Electrical equipment Tableware Control knobs Handles Laminates

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EPOXY RESIN

Epoxy resins come in a variety of forms (SYSTEMS) and are made of:-

• EPOXY RESIN • HARDENER They can cure rapidly or slowly, permitting

the selection of any form designed for an application. Depending on the epoxy selected, cure can be achieved at any temperature range from 5°C to over 200°C. Epoxy resin systems

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They can be poured into moulds or applied to Glass Fibre, Carbon Fiber or Kevlar Fiber matting in /on moulds.

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EPOXY RESIN

GLASS FIBRE

Glass Fibre Reinforced Plastic (GFRP) has a much higher elasticity than metals, GFRP was only used structurally where this characteristic was beneficial, or of little consequence.

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Examples of uses for GFRP are: Radomes and aerials (as a result of its Radar transparency)

Helicopter rotor blades Skin of honeycomb structure

where stiffness is either unimportant or imparted sub-structurally.

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GLASS FIBRE

CARBON FIBRE

Carbon fibre is produced by a special burning process. The result of this process are fibres which are 8 to 10 microns in diameter, (a human hair is 60 microns in diameter,).

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Carbon, whilst possessing enormous tensile strength along the length of the fibre are relatively easily damaged in shear. They are formed into a ‘tow’ (twist free bundle fibres). And a size (epoxy based coating) is applied.

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CARBON FIBRE

This protects the fibres and also helps bonding to the relevant resin system at a later stage.

The tows can also be woven into matting's making them easier to handle and work with, the resin system being added later (after mixing) in a messy process known as wet lay-up.

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CARBON FIBRE

In addition to conventional dry fibres, carbon can be supplied in a form known as “pre-preg”. In this condition the manufacturer has already added the resin system. The advantages are that health and safety risks are lower, in so far as no resin mixing is required (fume extraction etc.)

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CARBON FIBRE

Disadvantages are that specialist storage facilities are required to prolong the life of the pre-preg (typically 30 days at 20° C; up to 1 year at -18° C.).

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CARBON FIBRE

When carbon fibre is used as a repair medium for metallic structures, galvanic corrosion can be a problem. Scrim cloths, adhesive films and Ballatine balls are the common barrier methods of alleviating this problem.

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CARBON FIBRE

Properties of Carbon Fibre are: High strength High stiffness Low density Good fatigue Good vibration resistance X-ray transparency an Chemical inertness Brittle

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CARBON FIBRE

Examples of uses of Carbon Fibre are:

Aircraft Wings Aircraft Structures Formula 1 Nosecones/Rear Wings

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CARBON FIBRE

Kevlar is a yellow coloured Aramid fibre (an organic polymer). The structural grade Kevlar fibre, Kevlar 49, is characterized by excellent tensile strength and toughness but significantly inferior compressive strength compared to carbon.

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KEVLAR

The stiffness, density and cost of Kevlar are all lower than carbon; hence Kevlar may be found in many secondary structures as a hybrid with fibreglass.

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KEVLAR

Advantages of Kevlar The primary reason Kevlar is

becoming widespread in the aircraft industry is the materials excellent impact resistance. Although damage will occur under impact, it is localised and will not spread, unlike laminates of carbon or glass.

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KEVLAR

The result of an impact test in which a panel of glass fibre and a panel of Kevlar of equal stiffness were repeatedly hit to a load of 907kg, using a hemispherical rod, were as follows:

5 ply GFRP failed after 836 hits 5 ply Kevlar survived 10,000 hits

with only minor damage

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KEVLAR

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A Kevlar composite will fail via a ‘NON-CATASTROPHIC YIELDING MECHANISM’, (similar to metal), rather than the fracture mechanism typical of glass or carbon composites. When impacted, Kevlar has an initial elastic phase, where the material stretches to absorb the “impact energy” rather than fracturing of the structure as occurs in carbon and glass.

KEVLAR

This ability of Kevlar to withstand impact and continuous static loads results in excellent fatigue resistance.

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KEVLAR

Examples of uses for Kevlar are: Aircraft applications. Ranging from

interior mouldings, wing and body fairings, access panels, leading and trailing edges, landing gear doors, instrument panels and radomes, propellers, cargo bay liners and containers, engine noise absorption pads and engine blade containment rings.

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KEVLAR

Properties of Kevlar are: fibres can deteriorate under ultra-

violet light. Excellent fatigue resistance. Impact resistant. Energy absorbent. Poor compressive strength. Good Tensile Strength

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KEVLAR

ORGANIC MATERIALS

When using the term Organic Materials we are referring to materials that have come from nature. Such as:

Leather Sinew Bone Timber

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HARDWOODS

We get our hardwoods from broad leafed trees. The term hardwood can be misleading. It does not mean that they are “harder” than softwoods but because of their relatively short fibres they tend to be denser than softwoods

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Hardwood Density (kg/m³)

Moisture content %

Uses

Elm 550 12 Lock Gates Piles Outdoor Cladding

Oak 720 12 Ship Building House Building Furniture

Mahogany 720 12 Furniture

Ash 810 12 Vehicle Bodies Tool Handles

Teak 900 11 Indoor/Outdoor Furniture

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HARDWOODS

SOFTWOODS

About 80% of the wood used today is Softwood. It comes from quick growing trees with long spikey leaves such as conifers. These woods tend to have long fibres making them less dense than hardwoods

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Softwood Density (kg/m³)

Moisture content %

Uses

Spruce 420 13 General Construction work Boxes Cases

Scots Pine 510 12 General Construction work Furniture Flooring

Douglas Fir 530 12 Heavy Construction work Plywood

Larch 810 12 Outdoor Purposes Mining General Purposes

SOFTWOODS

These composites fall into 3 catorgries Laminated Boards

Particle Boards Fibre Boards

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WOOD COMPOSITES

WOOD COMPOSITES

Plywood is the most commonly known Laminated Board. It consists of thin layers of wood bonded together. To prevent warping and to give strength these boards are layered in such a way that their grains run 90° to each other.

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Particle Board is made from recycled materials such as sawdust or shavings that have been bonded together to form Chip Board. This Chip Board is used in the manufacturer of Kitchen Units

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WOOD COMPOSITES

Fibre Board is made from compressed fibres of differing length that have been bonded together. They include both Hardboards and Medium Density Fibreboard (MDF)

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WOOD COMPOSITES

WHAT ARE SMART MATERIALS?

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SMART MATERIALS

Smart materials are materials that CAN undergo a change to their properties WHEN there is a change to its working environment

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SMART MATERIALS

What Smart Materials do you know of in common everyday use?

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Piezoelectric Materials When you apply a force to certain

materials such as quartz you are causing a potential difference to be set up across the faces of the material at 90° to the force. This effect is known as the PIEZOELECTRIC EFFECT

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SMART MATERIALS

This effect is used in pressure sensors on sealing machines used in pharmaceutical manufacture, vibration recorders used on Health Usage Monitoring Systems and microphones

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SMART MATERIALS

We can also use this effect in reverse if we apply a voltage. This produces a stress in the material which can cause it to twist or indeed bend by a controlled amount. Aircraft manufactures are using these smart materials in the manufacture of new aircraft.

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SMART MATERIALS

SHAPE MEMORY ALLOYS (AKA MEMORY ALLOYS)

When deformed these materials will return to their original shape when heated OR when the external force is removed.

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SMART MATERIALS

These alloys contain special combinations of Copper, Zinc, Nickel, Aluminium and Titanium. They are used in medical applications as VASCULAR STENTS that are place in blocked or narrowing blood vessels. They use your bodies temperature to enlarge which opens the vessels improving flow. They are also used in the manufacture of Dental braces where the bodies temperature causes them to contract and exert pressure on the teeth

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SMART MATERIALS

MAGNETO-RHEOSTATIC FLUIDS Within these fluids are microscopic

magnetic particles that are suspended in a type of oil. When we apply a magnetic force these particle align themselves along the magnetic flux lines. This greatly restricts the flow of the fluid. This can cause the fluids viscosity to rapidly change from a fluid to almost a solid

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SMART MATERIALS

These fluids have been used in fast acting clutches, shock absorbers and flow control systems.

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SMART MATERIALS

ELECTRO-RHEOSTATIC FLUIDS These are very similar to Magneto-

Rheostatic Fluids in that they will become viscous in the presence of a static electric field, again they line themselves up with the flux lines which opposes the flow of the fluid

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SMART MATERIALS

These liquids are extremely fast acting and can change from a fluid to a stiff gel and back again in milliseconds. They are used in similar applications to Magneto-Rheostatic Fluids

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SMART MATERIALS

Material Recognition Assessment

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HOW ARE MATERIALS IDENTIFIED

As engineers you will need to be able to interpret the material requirements given on engineering drawings, plans and processes . This information is often given in abbreviated form.

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There may be occasions that you will have to draw material from stores when the storekeeper is not present for these reasons you have to have an understanding of how to identify different materials used within engineering.

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HOW ARE MATERIALS IDENTIFIED

The constituents of the different metals and alloys in use are specified by the British Standards Institution (BSI),they will also state the most appropriate use and operating conditions (especially high temperatures/pressures) for the material

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IDENTIFICATION CODING

There is also the European BS EN 10277 standards for steels

Previous identification methods for steels include:

BS 970 issued in 1991 BS 970 issued in 1955

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Material BS EN 10277:1999

BS 970:1991 BS 970:1995

Mild Steel 1.7021 210M15 EN 23M

Medium Carbon Steel

1.0511 080M40 EN 8

Tool Steel 1.3505 534A99 EN 31

Free Cutting Steel

1.0715 230M07 EN 1A

High Tensile Steel

1.0407/1.1148 605M36T EN 16T

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Supplier Manufactures often have their own coding systems, metal bars are often painted on their ends so that they can be easily identified at a glance, some use tags that correlate to certain information. Whatever system is used in your work place YOU should familiarise yourself with it.

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Material Colour Code

Mild Steel Red

Medium Carbon Steel Yellow

High Carbon Steel Purple/White

Free Cutting Steel Green

High Tensile Steel White

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Certificates of Conformity, (COCs) are issued by the Manufacture of the material and come in the form of a certificate, A-4 size, which should be attached to the material

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The COC itself gives a range of information of which some examples are:

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The Manufactures Name and address. The Manufactures QA Stamp. Dimensions and thickness of material. Composition of material. COC reference number. Batch number. Reference to which material conforms to, usually in the form of material specification.

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Batch Numbers are similar to use as serial numbers of components but are no longer stamped/etched or painted onto materials such as sheet metals due to the fact that the process of stamping such numbers induces stress, and paint can easily be erased in transit. Batch numbers are now found on the COC.

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SYMBOLS AND ABBREVIATIONS

The following is part of a typical title block used on an engineering drawing, containing the information on the material to be used

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TITLE BLOCK

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Title

Connector

Scale 1:1

Projection

Drawn: FB

Date: 25.10.13

Date: 25.10.13

Checked: MJ

Material:BDMS toBS070:040A.10

The material specified in this example is

BRIGHT DRAWN MILD STEEL BDMS The other information BS 070:040A.10

relates to it’s British Standards (BS) specification. This specifies the % of each of the ingredients of a material and its recommended uses

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TITLE BLOCK

The drawing itself may also give you some further information, such as the surface finish, heat treatment, surface hardness.

For Bar Stock, Sheet or wire it may also give you some dimensional information

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TITLE BLOCK

ABBREVILE TABLE FOR SOME COMMON METALS

Abbreviation Material

CI Cast Iron

SG Iron Spheroidal graphite Cast Iron

MS Mild Steel

BDMS Bright Drawn Mild Steel

CRMS Cold Rolled Mild Steel

SS Stainless Steel

Alum Aluminium

Dural Duralumin

Phos Bronze Phospher Bronze

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Abbreviation/Symbol Interpretation

ISO International Organisation for Standardisation

BS British Standard

BSI British Standard Institution

BH Brinell Hardness number

VPN Vickers pyramid hardness number

SWG Standard Wire Gauge

Ø 50 50 mm diameter

MS, Hex Hd Bolt-M8x1.25x50 Mild Steel Hexagonal headed, metric bolt 8mm diameter,1,25mm pitch,50mm long 158

ABBREVILE TABLE FOR SOME COMMON METALS

MEANINGS

Surface hardness is tested by pressing some form of indenter into the surface of the material and then using the dimensions of the indentation to calculate a hardness number

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Standard Wire Guage (SWG) is a means of classifiying a wires diameter or the thickness of sheet metal.

The higher the number the thinner the material.

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MEANINGS

FORMS OF SUPPLY

How do engineering materials begin their life?

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Metals begin their life as ores Plastics are derived from the by

products of oil distillation and from vegetable sources.

Timber is obtained from Forestry.

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FORMS OF SUPPLY

The ores for metals are smelted or otherwise extracted and produced into ingots. These then go on to secondary processing. This may occur at the same site.

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FORMS OF SUPPLY

Plastics are converted into powders, granules and resins

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FORMS OF SUPPLY

Timber is transported to mills for cutting and seasoning before use.

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FORMS OF SUPPLY

Once all of the manufacturing processes have been undertaken the materials are stored ready to be distributed to various engineering companies and merchants for use

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FORMS OF SUPPLY

METALS POLYMERS TIMBER

Ingots Powders Planks

Castings Granules Boards

Forgings Resins Composite Sheets

Pressings Sheet Rods

Bars Mouldings

Sheet Pipe/Tube

Plate Film

Pipe/Tube

Wire

Rolled Sections

Extrusions

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FORMS OF SUPPLY