copper and its alloys

TAFE NSW -Technical and Further Education Commission

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ENMAT101A Engineering Materials and ProcessesAssociate Degree of Applied Engineering (Renewable Energy Technologies)Lecture 16 – Copper and its alloys


Copper and its alloys

EMMAT101A Engineering Materials and Processes

Reference Text Section

Higgins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th ed, Butterworth Heinemann

Ch 16

Additional Readings Section


Copper and its alloys


Note: This lecture closely follows text (Higgins Ch16)


Copper (Higgins 16.1)


READ HIGGINS 16.1

Some history…

And for a bit more up-to-date action…

Bronze-age weaponryhttp://en.wikipedia.org/wiki/File:Bronze_age_weapons_Romania.jpg


Uses of copper


http://www.inmetmining.com


Worldwide Copper Production


Worldwide Copper Production may be nearing its peak.

Copper is closely linked to demands of industrial expansion– needed for both infrastructure and electrical products.

http://en.wikipedia.org/wiki/Peak_copper


Copper Price


It is also magnified by tightening supply as China and India increase demand.

So copper price rises on optimism.

Note the GFC drop.

http://www.kitcometals.com

The price of copper is sensitive to production demands (set by manufacturing outlook: i.e.

companies placing orders based on their projected production)


The extraction copper (Higgins 16.2)


READ HIGGINS 16.2The extraction of copper

Extraction of copper

The 2010 Copiapó mining accident in Chile’s San José

copper–gold mine. The 33 miners were trapped 700m

underground, surviving for a record 69 days before their

rescue through drilled holes.

Wikipedia

http://en.wikipedia.org/wiki/San_Jos%C3%A9_Mine

http://en.wikipedia.org/wiki/San_Jos%C3%A9_Mine

http://en.wikipedia.org/wiki/Copper_extraction_techniques

http://en.wikipedia.org/wiki/2010_Copiap%C3%B3_mining_accident


Properties of copper (Higgins 16.3)


READ HIGGINS 16.3

Conductivity (electrical and thermal)Corrosion resistanceDuctility

http://www.reuters.comhttp://www.sciencelearn.org.nz


Coppers and alloys (Higgins 16.4)


READ HIGGINS 16.4

Oxygen-free high-conductivity (OFHC) copper: Electrolytically refined: Electrical uses

'Tough-pitch' copper: Heat refined. Lower conductivity.

Deoxidised copper: Tough pitch copper deoxidised with phosphorus which improves weldability, but worse electrically. The Xstrata copper electrorefining tankhouse at

Copper Refineries in Townsville, Queensland, Australia.


Coppers and alloys (Higgins 16.4)


READ HIGGINS 16.4.1: Alloys of copper

1. Brasses: copper-zinc alloys2. Bronzes: copper-tin alloys

Phosphor bronzes: copper-tin-phosphorus alloysGunmetals: copper-tin-zinc alloys

3. Aluminium bronzes: copper-aluminium alloys4. Cupro-nickels: copper-nickel alloys

Nickel silvers: copper-zinc-nickel alloys5. Beryllium bronzes: copper-beryllium alloys


The brasses (Higgins 16.5)


READ HIGGINS 16.5: CAREFULLY!Brass: Up to 45% Zn, also some Sn, Pb, Al, Mn, Fe

Figure 16.1 The section of the copper-zinc equilibrium diagram which covers brasses of engineering importance. (Higgins)

Brass

http://en.wikipedia.org/wiki/Brass




Complete copper-zinc equilibrium diagram:Phases: a up to 37% Zn: Ductile: e.g. 70/30Cold working

b above to 37% ZnHot working

Tin: corrosionLead: machinablilty

http://pwatlas.mt.umist.ac.uk




READ HIGGINS 16.5: CAREFULLY!70/30 Brass: That’s copper/zinc ratio

(i) 70-30 brass as cast with cored crystals of a solid solution(ii) 70-30 brass, cold worked and then annealed at 600°C. The coring of the original cast structure has been removed by this treatment and recrystallisation has produced small crystals (twinned) of the solid solution a (Higgins Fig 16.2)




READ HIGGINS 16.5: CAREFULLY!Brass: Up to 45% Zn, also some Sn, Pb, Al, Mn, Fe

(iii) 60-40 brass as cast. This shows a typical Widmanstdtten structure and, on cooling, small a crystals (light) have precipitated from the b phase (dark).

(Higgins Fig 16.2)



Higgins




READ HIGGINS 16.5.1 'Shape memory' alloys'Shape memory' alloys have two distinct crystal structures that revert at a critical transformation temperature. Below the CTT structure is like martensite, and reverts back when heated above CTT.The shape change can be used to operate temperature-sensitive devices: automatic greenhouse ventilators, thermostatic radiator valves, de-icing switches, electric kettle switches and valves in solar heating systems.

Note:The most widely used shape memory alloy is the equi-atomic Nickel Titanium alloy known commercially as Nitinol.

http://www.doitpoms.ac.uk/tlplib/superelasticity/uses.php





Tin bronzes (Higgins 16.6)


READ HIGGINS 16.6Tin bronzes, contain up to 18% Sn (Tin) with smaller amounts of P, Zn, Pb

1. Wrought tin bronzes up to 7% tin. Sheet, wire, drawn rod.

2 Cast tin bronzes with 10 to 18 % tin, used mainly for bearings.


Bronzes (Higgins 16.6)



Aluminium bronzes (Higgins 16.7)


READ HIGGINS 16.7Two groups: cold-working alloys, and the hot-working alloys.

1. Wrought tin bronzes up to 7% tin. Sheet, wire, drawn rod.

2 Cast tin bronzes with 10 to 18 % tin, used mainly for bearings.

33 tonne propellor made from nickel aluminum bronze.qe-carrier.blogspot.com


Aluminium bronzes (Higgins 16.7)



Copper-nickel alloys (Higgins 16.8)


READ HIGGINS 16.8Cu and Ni complete solubility. Corrosion resistant.

16.8.1 Nickel-silvers


Other copper alloys (Higgins 16.9)


READ HIGGINS 16.9

16.9.1 Beryllium bronzeNon-sparking tools

16.9.2 Copper-chromiumConductive & strong.

16.9.3 Copper-cadmiumDrawn electrical wire

16.9.4 Copper-telluriumMachined electrical

16.9.5 Arsenical copperThermal



Online Resources.

Cast Iron

http://www.msm.cam.ac.uk/phase-trans/2001/adi/cast.iron.html

Extraction of copper



http://en.wikipedia.org/wiki/Copper_extraction_techniques


GLOSSARY

BrassBronzeElectrolysisPhosphor bronzesGunmetalsAluminium bronzesCupro-nickelsNickel silversBeryllium bronzes



QUESTIONSMoodle XML: Some questions in 10105 Steel

1. Define all the glossary terms.2. Describe the name, uses and properties of 70/30 brass.3. What constituents determine the names brass and bronze?4. Describe how electrical grade copper is made.5. Explain why applications that used copper alloys (e.g. cartridge brass) are being

replaced with aluminium and mild steel.6. Using current prices from LME (London Metals Exchange), determine the cost of

ingredients for 1 tonne of High-tin bronze – Higgins Table 16.2.7. Describe the following copper-based alloys and their uses. Monel, gunmetal,

gilding metal, cartridge brass, free-cutting brass8. What ingredient is added to brasses and bronzes to improve machability. Describe

how this works in reference to microstructure.9. Silver is the most conductive metal. By comparison, copper is 97%, gold 71% and

aluminium 58%. Using current prices of each metal, rank conductivity per dollar. 10.Research the advantages and disadvantages of using aluminium vs copper for

use as electrical conductors. Why is strength and conductivity difficult?


copper and its alloys

Documents

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