1. Technical Materials (II): Metals
Department of Technology
I.E.S. Ramiro de Maeztu
Madrid

2. Metal Properties
• Metal is a good conductor of heat and
electricity
• High mechanical endurance
• High fusion temperature
Cast Iron
Tensile
Strength
Steel
• Metal is a heavy material
Copper
Tin
Zinc
Aluminum
Magnesium
Titanium
18 kg
70kg
18kg
5kg
3kg
10Kg
18kg
70kg
Mass(per m3)
7600kg
7800kg
8800kg
7300kg
7400kg
2700kg
1700kg
4500kg
Fusion
temperature
1100ºC
1500ºC
1083ºC
231ºC
419ºC
660ºC
650ºC
1800ºC

3. Metal Properties
• It´s a tough material
• It´s a ductile, malleable material
•Some of them have magnetic properties
• It´s an easily recyclable material

4. Classification of Metals
World Metal Production
Metals are classified in two groups:
oFerrous Metals: iron and its alloys.
oNon-Ferrous Metals: metals that do not contain iron .
This is because iron is the most used metal in the world

5. Ferrous Metals
Pure iron
•Iron is an abundant metal.
•Iron is fragile and brittle.
•Iron rusts easily.
•Iron has very good magnetic properties.
Due to his low endurance, pure iron is not used. So it´s mixed with a little
amount of carbon obtaining ferrous alloys.
How changes carbon the iron properties?
A bigger amount of carbon in the ferrous alloy increases the hardness
but decreases the tenacity, so the alloy becomes more fragile.

6. Ferrous Metals: Ferrous Alloys
• Soft Iron( C<0,1%)
It´s like pure iron. At first it was very used because it was easy to obtain. At present time it´s
used to make electromagnet nucleus thanks to its very good magnetic property.
•Soft, due to its low iron content.
•Silvery colour.
•Electric and electronic applications.

7. Ferrous Metals: Ferrous Alloys
• Steel ( 0,1%<C<2% )
It´s the most used ferrous alloy thanks to its good properties.
•Ductile and malleable.
•High mechanical endurance.
•The amount of carbon increases hardness and fragility.
Steel mixed with other metal increases endurance (vanadium) and becomes
stainless (chrome and nickel).

8. Ferrous Metals: Ferrous Alloys
• Cast Iron ( 2%<C<5% )
• Harder and more fragile than steel.
• It has low ductility but it´s a malleable alloy with magnesium.
• It melts more easily (at a lower temperature) than steel.
It´s used to make complicated
parts by sand casting (aka sand
molded casting) and to make
hard tools like rasps.

9. Non-Ferrous Metals: Pure Metals
• Copper
•Red colour
•Excellent thermal and electrical
conductor
•Corrosion resistant
•Good welding
•Very ductile and malleable
• Tin
•Bluish white shiny colour
•Soft
•Corrosion resistant
•Low melting point

10. Non-Ferrous Metals: Pure Metals
• Zinc
•White colour
•Very corrosion resistant
• Aluminum
• White shiny colour
• Light and good endurance
• No toxic
• Cheap
•Stainless

11. Non-Ferrous Metals: Pure Metals
• Magnesium
•Very light
•Expensive
•Violent reaction with oxygen
• Titanium
•Very expensive
•Endurance like steel but quite lighter.
•Biocompatible

12. Non-Ferrous Metals: Pure Metals
• Gold
•The most malleable and ductile metal
•Very corrosion resistant
•High thermal and electric conductivity
•High economic value
• Lead
•Grey colour
•Very soft and heavy
•Low melting point
•Ductile and malleable
•Very toxic

13. Non-Ferrous Metals: Alloys
• Brass
(Copper+Zinc)
•Yellow colour
•Very ductile and malleable
•Good tensile endurance
• Bronze
(Copper+Tin)
•Dark yellow colour
•More endurance than brass
•Very corrosion resistant
•Good sonority
•Very fluid when melting, good for
molding.

14. Non-Ferrous Metals: Alloys
• Aluminum, Copper & Magnesium
•Lightness and more endurance
than pure aluminum.
• Magnesium & Aluminum
•This alloy is more resistant than
each metal.
• Titanium & Aluminum
• Cheaper than pure titanium parts.

15. Extraction of metals
Most metals are in nature as minerals.
Chalcosite: copper rich
Pure gold
Pyrite: iron rich
Bauxite: aluminum rich
Hematite: iron rich
Limonite: iron rich

16. Obtaining cast iron and steel
Coal
Iron ore
Limestone
Blast furnace
Refining
Furnace
Ladle Furnace
Torpedo
ladle
We can obtain cast iron by melting of coal,iron ore and limestone at the blast furnace , then we
carry it to the refining furnace using torpedo furnace and ladle furnace. In the refining furnace
the amount of carbon to obtain steel decreases.

17. Obtaining of metals by electolysis
A high voltage electric current through the
melted metal is used.
Pure metal is attracted by the negative electrode
(remember that metal atoms are positive).
We can use this method to obtain metals like
copper and aluminum.

18. Metal Working
To measure
and to mark
To fasten and
to bend
To cut
To join
To smooth
or refine
To drill
To finish

19. Metal Working
Compass
•To measure and to mark
Steel rule
•To hold/fasten and to bend
Square
Pliers
Vise
, F - clamp
and G-clamp

20. Metal Working
•To cut
Metal Scissors
Hacksaw
•To drill
Drill bits
Drill

21. Metal Working
•To
smooth/refine
•To join
Welding
Wire wool
Rasp
Metal polisher
Screwing
Riveting

22. Metal Working
•To finish
Burnished
Primer

23. Metal Working: Machining
• Milling: we can use different mill bits
to shape a piece from a block of metal.

24. Metal Working: Machining
• Turning: we can obtain metallic parts
with cylindrical symmetry.

25. Metal Working: Machining
• Computer Numerical Control (CNC): it´s to make metallic
pieces automatically and with a very high accuracy.

26. Molding and Metal Forming
• Moulding: Sand Casting
Sand is used to make a mold and fill
this with molten metal. It allows you
to make complicated parts as the
engine block of a car.

27. Moulding and Metal Forming
• Lamination
We use rolls that compress
the metal to obtain sheets
and metal profiles.

28. Molding and Metal Forming
• Stamping
A metal sheet is compressed
by a press to take the form
of the mold.
• Die-Cutting
It´s cutting pieces of a metal
sheet using a press.

29. Molding and Metal Forming
• Forge
We use the fire and hammer over the
anvil to shape the soft steel and get
handmade pieces of metal.
Anvil

30. THE END