Lecture non-ferrous

8/7/2019 Lecture non-ferrous

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LectureLectureNon ferrous metals and alloys and their heat

treatment


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MetalsMetalsy All metals belong to one of these two groups.

y Ferrous metals are metals, which are mainly made of ironwith small amounts of other metals or elements added inorder to give the correct properties. Almost all ferrous metalsare magnetic and can be picked up with a magnet. Thesemetals rust or oxidise if not treated as they contain iron.

y Non-Ferrous metals are those metals, which do notcontain iron. These metals are not magnetic and cannot be

attracted by a magnet. Examples of these are aluminium,copper, lead, zinc and tin. These metals do not oxidise as theydo not contain iron.


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New NonNew Non--metalsmetals

y Following metals have been available after

world war II.


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Common non ferrous metalsCommon non ferrous metals


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Material Type Uses Properties

Mild steel Ferrousmetal

Nails, screws, nuts and

bolts, girders, car bodies

Tough, malleable, high tensile

strength, easily joined, poor

resistance to corrosion,general-purpose metal.

Brass Non-ferrousmetal

Ornaments, boat fittings,

castings.

Corrosion resistant, polishes

well. Hard, easily joined, good

conductor of heat and

electricity.

Copper Non-

ferrousmetal

Hot water storage

cylinders, central heatingpipes, electrical wires,

copper clad electronics

boards

Good conductor of heat and

electricity, corrosion resistant,easily joined, polishes well,

solders and brazes well,

expensive to buy.

Stainlesssteel

Alloy Sinks, cutlery, dishes,teapots

Hard and tough, resists wear,

corrosion resistant, difficult to

cut and file.

Aluminium Non-ferrousmetal

Kitchen cooking utensils,

pans, packaging, cans,window frames

High strength to weight ratio,

light, soft, difficult to join, goodconductor of heat and

electricity, corrosion-resistant,

polishes well.


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Ti &Mg alloys Ni alloys

Superalloys

Non-ferrous

Metal Alloys

Ferrous

Cu alloys

Pure CuBrassesBronzesCupronickelBe-copperNickel silver

Al alloys

Alloying

ElementsCuMgMnSi

Zn

Alloying

Elemen

ts

AlZnMnV

Refractorymetals

Nb (2468rC)Ta (2996rC)W (3410rC)Mo (2617rC)

Fe-basedNi-based

Co-based

Monel

Inconel

Hastealloy

NonNon--ferrous Alloysferrous Alloys


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General Properties of Al

General Properties of Al

y Low density (2.3g/mm3) ~1/3 of that of steel

higher strength-to-weight ratio

y High electrical conductivity 60% of that ofCu

higher conductivity-to-weight ratio

High thermal conductivity

y

High oxidation resistancey Non-magnetic

y Non-toxic


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Properties of aluminiumProperties of aluminium


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General Properties of AlGeneral Properties of Al contdcontd

y Ductile and good formability - easy to process

y Easily machined, cast and most are weldable

y Most recyclable metal - only 5% of production

energy required.

y Al alloys are used mostly for four reasons:

specific strength

corrosion resistance

electrical conductivity

nontoxity.


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Containers andpackaging (non-

toxic)

Electricalconductors

(conductivity)

Architecturalconstruction(corrosionresistance)

Structuralapplications

(strength-to-weight ratio)

Aeroplane wing made of Al alloysfor their high strength-weight ratio

Al and its AlloysAl and its Alloys


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Wrought Al and its AlloysWrought Al and its Alloysy Pure Al is too soft for structural applications.

A single crystal of Al can not even support its own weight

y Therefore it is alloyed to improve strength.

y Common five elements (usually more than one):Cu,Mn,

Mg, Zn, Siy Al alloys are also hardened by cold working (rolling) and

by precipitation hardening (heat treatment).

y Typical mechanical properties:

Y

oungs modulus:~70

G

Pa (steel~

210G

Pa) Yield strength: 100~400MPa

UTS: 200-600MPa

Ductility: up to 30%


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Series Alloying

Elements

Property Overview Example Applications

A1xxx pure Al (>99%) yExtremely low strengthyHigh conductivity

119999.99% Al

Electrical conductorsChemical process equipment

Al foil

A2xxx Cu yHigh strength after

yheat treatment

yModerate ductility

yNot weldable

2014

Al-4.5Cu-1Si-0.6MgAircraft structures

Automotive body panels

A3xxx Mn yModerate strengthyHigh ductility

yExcellent corrosion

resistance

3003Al-1.5Mn

Al cansCooking utensils

Roofing sheet

A4xxx Si yModerate strength

yGood corrosion

resistance

yLow duct

ility

4043

Al-1.5MnArchitectural applications

A5xxx Mg yReasonable strengthyRapid work hardening

yHigh corrosion resistance

5005

Al-1.0MgBoat hullsStructural plate/flooring

A6xxx Si +Mg yMedium strengthyGood weldability

yGood corrosion resistance

6061

Al-1Mg-0.6SiArchitectural extrusionsGeneral extrusions

A7xxx Zn yHighest strengthyWeldable

7075Al-6Zn-2.5Mg-1.5Cu High strength aircraft components


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DivisionDivision


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Casting alloysCasting alloys

Sand CastingHigh Temperature Alloy,

Complex Geometry, Rough

Surface Finish

Investment CastingHigh Temperature Alloy, Complex

Geometry, Moderately Smooth

Surface Finish

Die CastingHigh Temperature Alloy,

Moderate Geometry,

Smooth Surface


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Sand CastingSand Castingy

Description: is used to make large parts.Moltenmetal is poured into a mold cavity formed out ofsand (natural or synthetic).

y Various core materials can be used.Molds are

broken to remove castings. Specialized bindersnow in use can improve tolerances and surfacefinish.

y Metals:Most castable metals. typically Iron, but

also Bronze, Brass, Aluminumy Size Range: Limitation depends on foundry

capabilities. Ounces to many tons.


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Die castingDie casting

y Description:Molten metal is injected,under pressure, into hardened steel dies,often water cooled. Dies are opened, and

castings are ejected.y Metals: Aluminum, Zinc,Magnesium, and

limited Brass.

y Size Range: Not normally over 2 feetsquare. Some foundries capable of largersizes.


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Die CastingDie Casting HotHot--ChamberChamber

CastingCasting

Cycle in hot-chamber casting:

(1) with die closed and plunger withdrawn,

molten metal flows into the chamber;

(2) plunger forces metal in chamber to flow into

die, maintaining pressure during cooling and

solidification; and

(3) plunger is withdrawn, die is opened, and

solidified part is ejected.

Finished part is shown in (4).


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Ti &Mg alloys Ni alloys

Superalloys

Non-ferrous

Metal Alloys

Ferrous

Cu alloys

Pure Cu

BrassesBronzesCupronickelBe-copperNickel silver

Al alloys

Alloying

ElementsCuMgMnSiZn

Alloying

Elemen

ts

AlZnMnV

Refractorymetals

Nb (2468rC)

Ta (2996rC)W (3410rC)Mo (2617rC)

Fe-based

Ni-based

Co-based

Monel

Inconel

Hastealloy

NonNon--ferrous Alloysferrous Alloys


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Production ofCuProduction ofCu

y First evidence ofCu ~5000BC

y Modern Smelting:

2CuFeS2 + 2SiO2 Cu2S + 2FeSiO3 + 2SiO2

thenCu2S + O2(air) 2Cu + SO2 (blister Cu)

y Blister Cu is refined by electrolysis to 99.99%Cu

heat

heat


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y Sufficient strength to beused analloyed.

y Density=8.93g/mm3

y Very ductiley Excellent electrical and

thermal conductivity

y Good corrosion

resistancey Forms oxide layer

which prevents itsfurther corrosion


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50% copper produced is madeinto electrical conductors

Cu

Cu

General Properties

General Properties

y Yield strength: 20-200MPa

y Tensile: 200-400MPa

y Youngs modulus: 117GPa

y Excellent formability

y temperature embrittlement

y Castable and weldable

y Corrosion resistant

y High thermal conductivityy High electrical conductivity


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Beryllium CopperBeryllium Copper

y Cu with 1.5-2.0%Be.

precipitation hardened, high strength, used for

springs and clips in electrical applications.

y

Properties: Yield Strength: up to 1000MPa

UTS: up to 1500MPa

Ductility:


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y It is used for,

y Instrument springs

y Flexible bellows

y Corrugated diaphrams

y Bourdon tubes of pressure guages


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BrassBrassy Cu with up to 50%Zn.

y Relatively easy to cast E-brass: up to 35%Zn

x Mallaeble and used in forgings (eg rivets,

red-brass: 2%Zn-10%Snx Gunmetal

yellow-brass: 30%Znx Used when sever plastic deformation is required

Naval Brass:40%Zn-1%Snx

Similar to -brass but with 1%Sn for corrosionresistance

brass:40-50%Znx Can only be worked hot.

x Strongest of all brasses.


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OtherC

uOtherC

u--alloysalloysy Copper-Nickel Alloys (Cupronickel, 90/10 and70/30)

High ductility and formability

Strengthened by cold working

y Copper-Zinc-Nickel Alloys (Nickel Silver)

Pale yellow at 10-12%Ni, silver white at 20-30%Ni

Decorative applications and silver plated dinnerware


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CuproCupro--nickel alloysnickel alloys

y These two metals are completely soluble

in liquid as well as in solid state.

y They are relatively expensive,but having

y High strength

y Ductility



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TinTin--bronze alloysbronze alloys

y Alloys of copper and tin together with thedeoxidiser.

y This is essential to prevent the tin content

oxidizing during casting or hot working,bcozoxidation of tin would result in a weak

scratchy bronze.

y Two deoxidisers commonly used are,

y Phosphorous in the phosphor bronze alloys.

y Zinc in the gunmetal alloys.


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y Tin-bronze alloys are more expensive

than brass alloys,but

y More stronger


yWear resistant

y Give sound pressure castings which are

widely used for steam and hydraulic valve

bodies and mechanisms.


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AlAl--bronze alloysbronze alloys

y Predominant metal present is copper.

y Al is alloying element.

y These alloys are more expensive then Tin-

bronze alloys but,

y Are more corrosion resistant at high

temperatures


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SummarySummary

y Aluminium

Used for lightweight, corrosion resistance,

conductivity or non-toxicity

Either wrought (common alloy6061

, 2014

, 500

5) Or cast (eg A380, 356)

y Cu

Pure Cu used for conductivity properties

Alloys used for strength, conductivity formability andcorrosion resistance.


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Magnesium alloysMagnesium alloys

y Mg is the lightest of engineering metals with a

density of1.7g/mm3

y

Electrical and thermal conductivity is abt60%

that of high conductivity copper.

y High affinity of oxygen and burns readily

y Not as strong as aluminum alloys,but these

alloys have much lower density so preferred

in the applications where high strength/weight

ratio is desired


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Zinc AlloysZinc Alloys

y Pure metal is relatively weak.

y Zinc based alloys have high fluidity,whichenables complex castings with thin

sections to be made.y Low meling point.

y Easy polishing and electroplatingproperties.

y Adequate strength for small components.

y Donot react with and erode the die steel.

Lecture non-ferrous

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