ENMAT101A Engineering Materials and Processes
Associate Degree of Applied Engineering
(Renewable Energy Technologies)
Lecture 7 – Mechanical shaping of metals
www.highered.tafensw.edu.au
TAFE NSW -Technical and Further Education Commission
Mechanical Deformation of Metals
Reference Text
Section
Higgins RA & Bolton, 2010. Materials for Engineers and Technicians,
5th ed, Butterworth Heinemann
Ch 7
Additional Readings
Section
Sheedy, P. A, 1994. Materials : Their properties, testing and selection
Ch 13
Callister, W. Jr. and Rethwisch, D., 2010, Materials Science and
Engineering: An Introduction, 8th Ed, Wiley, New York.
N.A.
Ashby, M.F., 2011. Materials Selection in Mechanical Design, 4th Ed,
Butterworth Heinemann, Oxford, UK.
Ch 13
EMMAT101A Engineering Materials and Processes
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Ashby: Fig 13.2
The classes of
processes
EMMAT101A Engineering Materials and Processes
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Hot-working processes (Higgins 7.2)
Hot Working processes are carried out above the recrystallisation
temperature of the material.
7.2 Hot Working Processes
7.2.1 Forging
7.2.2 Hot-rolling
EMMAT101A Engineering Materials and Processes
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Hot-working processes: Forging (Higgins 7.2.1)
VIDEO:
Open-die forging can produce forgings from a kg to more than 150
tonnes.
“Open-die” means the metal is not confined laterally during forging.
The process works progressively from the starting stock into the desired
shape. Flat-faced dies are usual.
Wide range of shapes and sizes are possible, especially suited to large
custom parts like a ship’s propeller shaft.
Seamless Rolled Ring Forging: Starts with a cast
billet, then upset and punched to form a donut shape,
then rolling and squeezing (or in some cases,
pounding) the donut into a thin ring. Ring diameters
can be anywhere from a 100mm to 10m.
EMMAT101A Engineering Materials and Processes
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Hot-working processes: Hot-Rolling (Higgins 7.2.2)
Hot Rolling (Billet to plate/sheet):
Dalarna University www.du.se
(Creative Commons)
Breaking down billets (large thick slabs
cast from the furnace) into successively
thinner plate, and finally sheet.
Fun and Games with Hot Rolling…
“Cobble” = British terminology
“Miss-roll = US terminology
HD-720
Cobble: http://www.youtube.com/watch?v=NnqZ-ybpdhQ
Cobble 2: http://www.youtube.com/watch?v=v4p-YCtbhMQ
EMMAT101A Engineering Materials and Processes
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Hot-working processes: Extrusion (Higgins 7.2.3)
Like squeezing toothpaste from a tube, material is forced through a die
and is plastically deformed into the cross-section of the die.
The die hole can be almost any shape, (e.g. a circular die will make a rod)
Mostly used for low
temperature metals: copper
pipes, aluminium extrusions.
Steel can only be drawn or
hot rolled, but not extruded in
the same way as aluminium.
Pity. Would have been a nice
way to make steel pipe.
openlearn.open.ac.uk
EMMAT101A Engineering Materials and Processes
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Hot-working processes: Extrusion (Higgins 7.2.3)
Extruding a hollow shape is an obvious problem. How do you hold the die
that forms the hole?
Extrusion bridge die making a
hollow section product.
Note: in reality, the die and
ring are held together.
http://openlearn.open.ac.uk/mod/oucontent/view.php?id=399740&section=3.5
EMMAT101A Engineering Materials and Processes
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Hot-working processes: Extrusion (Higgins 7.2.3)
Aluminium dominates the extrusion industry because the metal has
excellent ductility without the need for extreme temperatures. It is also an
obvious choice for window frames, structural and decorative parts, and
almost anything of a constant cross-section.
Heated to about 900oF (480oC) to
keep it well above the
recrystallisation temperature
(150oC).
The design of the extrusion profile
effects extrusion performance. (E.g.
Better to have symmetry, avoid long
flats, minimize internal holes, etc…)
PBCLinear
EMMAT101A Engineering Materials and Processes
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Hot-working processes 3 (Higgins 7.2)
Other Hot Working Processes
Hot forming of Coil Springs:
http://www.youtube.com/watch?v=6BplSiK8qK8
Friction Welding:
http://www.youtube.com/watch?v=5JbnDXw-0pM
EMMAT101A Engineering Materials and Processes
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Cold-working processes (Higgins 7.3)
Cold Working processes are carried out below the recrystallisation
temperature of the material.
See text:
7.3 Cold Working Processes
7.3.1 Cold-rolling
7.3.2 Drawing
7.3.3 Cold-pressing and deep-drawing
Bolts: http://www.youtube.com/watch?v=7PQyant3mCc
7.3.4 Spinning
7.3.5 Stretch-forming
7.3.6 Coining and embossing
7.3.7 Impact-extrusion
EMMAT101A Engineering Materials and Processes
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Cold-working processes: Cold Rolling (Higgins 7.3.1)
Cold Rolling Steel Sheet:
Steelmaking: Cold Rolling
by CorusBCSATraining
Roll Curving Steel plate for Wind Turbine Tower
http://www.tsgnorthamerica.com
EMMAT101A Engineering Materials and Processes
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Cold-working processes: Drawing (Higgins 7.3.2)
Cold Drawing of Hexagonal Bar
http://www.youtube.com/watch?v=72JWZAWZp5Q
EMMAT101A Engineering Materials and Processes
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Cold-working processes:
Cold Pressing and Deep Drawing (Higgins 7.3.3)
Forming Bolts
http://www.youtube.com/watch?v=7PQyant3mCc
EMMAT101A Engineering Materials and Processes
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Cold-working processes:
Spinning (Higgins 7.3.4)
Metal Spinning
http://www.youtube.com/watch?v=7PQyant3mCc
EMMAT101A Engineering Materials and Processes
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Cold-working processes:
Stretch-forming (Higgins 7.3.5)
Stretch Forming
http://www.youtube.com/watch?v=eSVi7dC5L_Q
EMMAT101A Engineering Materials and Processes
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Cold-working processes:
Coining and embossing (Higgins 7.3.6)
Stamping
http://www.youtube.com/watch?v=I7uBmlwxXRU
EMMAT101A Engineering Materials and Processes
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Cold-working processes:
Impact Extrusion (Higgins 7.3.7)
Impact Extrusion
http://www.youtube.com/watch?v=zMhVPId-pRA
EMMAT101A Engineering Materials and Processes
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Cold-working processes:
Roll Forming
Roll Forming – Roofing
http://www.youtube.com/watch?v=HrDegG_zkWY
Spiral Ducting
http://www.youtube.com/watch?v=fIe8PQXNrUo
ERW Pipe Forming (5” or 125mm)
http://www.youtube.com/watch?v=77utCIwKSn4
EMMAT101A Engineering Materials and Processes
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Powder Metallurgy (Higgins 7.4)
Powder Metallurgy (PM) involves pressing the
powder and then heating (above recrystallisation
but below the melting point) – called sintering –
which binds the particles together.
See text:
7.4.1 Uses of powder-metallurgy
7.4.2 Cemented carbides
7.4.3 Sintered-bronze bearings
Powder Metallurgy
http://www.youtube.com/watch?v=_0wd8sgNIOg
EMMAT101A Engineering Materials and Processes
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Machining metals (Higgins 7.5)
Machining is a cold-working process in which the cutting edge of a tool
forms shavings or chips of the material being cut.
See text: Higgins 7.5
Machining Centre: 5 axis various jobs
http://www.youtube.com/watch?v=0LCaRqQ8Qf8
High Speed Video: Milling Cutter
http://www.youtube.com/watch?v=IUBQN1JfY80
Machining a large shaft – Lathe
http://www.youtube.com/watch?v=ObsvfP5Nrw4
EMMAT101A Engineering Materials and Processes
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Profile Cutting
This is for cutting sheet material. Usually CNC
• Laser. Fast, accurate, good finish, many materials. Finest kerf. Fussy
maintenance.
High speed laser cutting
http://www.youtube.com/watch?v=RQIJSsbvolc
• Water jet: Almost any material. No heat damage.
Water jet cutting bullet-proof glass
http://www.youtube.com/watch?v=KmUWA_oXDEQ
EMMAT101A Engineering Materials and Processes
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Profile Cutting
This is for cutting sheet material. Usually CNC
• Flame Cut (Gas): Cheaper system, good for thick steel plate. Worst
quality.
High speed laser cutting
http://www.youtube.com/watch?v=Zy3g4-D1ZeA
• Plasma: Better finish than flame cut, but cheaper than laser.
CNC Plasma
http://www.youtube.com/watch?v=FHUs_u27IpE
• CNC router: Typically wood, plastic and soft metals (e.g. thin aluminium),
often held down by vacuum onto a spoil board (MDF)
EMMAT101A Engineering Materials and Processes
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Video
Forming & Shaping Metal
Davis, John. Warriewood, NSW : Classroom Video, c2002. DVD (22 min.)
Hot Forming, Cold Forming, Machining
Mt Druitt College Library: DVD 671.3/FORM
Recommended Viewing: All sections.
EMMAT101A Engineering Materials and Processes
TAFE NSW -Technical and Further Education Commission
Online Properties Resources.
Graphical comparison of materials properties.
DoITPoMS: Dissemination of IT for the Promotion of Materials Science
Wikipedia: Materials properties
Forming: Forging, Rolling, Extrusion, Machining
CorusBCSATraining
http://www.youtube.com/user/CorusBCSATraining
EMMAT101A Engineering Materials and Processes
TAFE NSW -Technical and Further Education Commission
GLOSSARY
Hot forming
Cold forming
Recrystallisation
Annealing
Work Hardening
Stress Relieving
Drawing
ERW
CNC
Profile Cutting
Plasma Cutting
Laser Cutting
Oxy Cutting
Water Jet Cutting
Open Die Forging
Upset Forging
Cavity Forging
Coolant
Facing
Turning
Metal Spinning
Roll Forming
Extrusion
Hot Rolling
Cold Rolling
Powder Metallurgy
Sintering
Drawing
Blanking
Bending
Stretching
EMMAT101A Engineering Materials and Processes
TAFE NSW -Technical and Further Education Commission
QUESTIONS
Callister: NA
Moodle XML: 10107 Processing
1. Define all the glossary terms.
2. Explain which type of process would be used for making railway tracks and
compare it to the process of making road crash barriers. Explain the difference.
3. Why are aluminium and copper based metals extruded, but not steel.
4. Explain the process of making an ERW round pipe.
5. Make a table comparing the various profile cutting technologies. Compare
machine cost, running cost, speed, accuracy, thickness, material range.
6. CNC if far superior to manual control of a machining operation. Why do we still
have manual machines at all?
7. A metal gear needs to be manufactured in the tens of thousands. Compare the
process options of powder metallurgy, machining, casting and forging. Include
cost of die, material costs, running costs, speed, accuracy, product
performance. (See: http://openlearn.open.ac.uk/mod/oucontent/view.php?id=399740&section=3.9)
EMMAT101A Engineering Materials and Processes
TAFE NSW -Technical and Further Education Commission