Coppers and alloys

ENMAT101A Engineering Materials and Processes

Associate Degree of Applied Engineering

(Renewable Energy Technologies)

Lecture 16 – Copper and its alloys

TAFE NSW -Technical and Further Education Commission www.highered.tafensw.edu.au

Copper and its alloys

Reference Text

Higgins RA & Bolton, 2010. Materials for Engineers and Technicians,

5th ed, Butterworth Heinemann

Section

Ch 16

Additional Readings Section

TAFE NSW -Technical and Further Education Commission

EMMAT101A Engineering Materials and Processes

Copper and its alloys

Note: This lecture closely follows text (Higgins Ch16)



Copper

(Higgins 16.1)

READ HIGGINS 16.1

Some history…

Bronze-age weaponry http://en.wikipedia.org/wiki/File:Bronze_ag e_weapons_Romania.jpg

And for a bit more up-todate action…



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.



Copper Price

The price of copper is sensitive to production demands (set by manufacturing outlook: i.e. companies placing orders based on their projected production)

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 extraction copper

(Higgins 16.2)

READ HIGGINS 16.2

The 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.

Extraction of copper


Wikipedia


Properties of copper

(Higgins 16.3)

READ HIGGINS 16.3

Conductivity (electrical and thermal)

Corrosion resistance

Ductility http://www.sciencelearn.org.nz

http://www.reuters.com



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 alloys

2. Bronzes: copper-tin alloys

Phosphor bronzes: copper-tin-phosphorus alloys

Gunmetals: copper-tin-zinc alloys

3. Aluminium bronzes: copper-aluminium alloys

4. Cupro-nickels: copper-nickel alloys

Nickel silvers: copper-zinc-nickel alloys

5. Beryllium bronzes: copper-beryllium alloys



The brasses

(Higgins 16.5) Brass

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)



The brasses

(Higgins 16.5)

Complete c opper-zinc equilibrium diagram:

Phases: a up to 37% Zn:

Ductile: e.g. 70/30

Cold working b above to 37% Zn

Hot working

Tin: corrosion

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



The brasses

(Higgins 16.5)


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)



The brasses

(Higgins 16.5)


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



Higgins


The brasses

(Higgins 16.5)

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 16.6

Tin 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)



Bronzes

(Higgins 16.6)



Aluminium bronzes

(Higgins 16.7)


Two groups: coldworking 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)


Cu and Ni complete solubility. Corrosion resistant.

16.8.1 Nickel-silvers





Other copper alloys

(Higgins 16.9)


16.9.1 Beryllium bronze

Non-sparking tools

16.9.2 Copper-chromium

Conductive & strong.

16.9.3 Copper-cadmium

Drawn electrical wire

16.9.4 Copper-tellurium

Machined electrical

16.9.5 Arsenical copper

Thermal



Online Resources.

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

Extraction of copper



GLOSSARY

Brass

Bronze

Electrolysis

Phosphor bronzes

Gunmetals

Aluminium bronzes

Cupro-nickels

Nickel silvers

Beryllium bronzes



QUESTIONS

Moodle 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 brass

8. 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?



Coppers and alloys

ENMAT101A Engineering Materials and Processes

Associate Degree of Applied Engineering

(Renewable Energy Technologies)

Lecture 16 – Copper and its alloys

Copper and its alloys

Copper and its alloys

Note: This lecture closely follows text (Higgins Ch16)

Copper

Uses of copper

Worldwide Copper Production

Copper Price

The extraction copper

Properties of copper