Metals

Question 1

Where do metals come from?

Answer 1

Metals come from metal ores

Question 2

Why are metals non-renewable and unsustainable?

Answer 2

They come from ores and ores do not re-grow when we dig them up meaning metals are non renewable and unsustainable.

Question 3

What is the ore of iron?

Answer 3

Magnetite and haematite

Question 4

What is the ore of copper

Answer 4

Chalcopyrite

Question 5

What is the ore of aluminium?

Answer 5

Bauxite

Question 6

What is the ore of lead

Answer 6

Galena

Question 7

What is the ore of tin?

Answer 7

Cassiterite

Question 8

What is the ore of zinc?

Answer 8

Zinc blende

Question 9

What is the structure of metals?

Answer 9

All metals are made up of crystals. Each crystal has a boundary that is firmly bonded to the boundary of a neighbouring crystal

Question 10

How can you distinguish the nature of a metal?

Answer 10

It depends very much on the nature of the crystal?

Question 11

What do we use to extract metal?

Answer 11

We use a blast furnace

Question 12

How does a blast furnace work?

Answer 12

1. Solid raw materials - iron ore, coke, limestone - are added from the top of the blast furnace.
2. Hot air is blown in to the bottom of the blast furnace and provides the oxygen for the coke (carbon) to burn.
3. Iron oxide in the iron ore reacts and changes to iron. Molten iron trickles to the bottom of the furnace.
4. Limestone reacts with impurities to form a slag that floats on the iron.
5. Waste gases are removed to a treatments plant.

Question 13

What are ferrous metals?

Answer 13

These are metals that contain iron.
They also corrode if unprotected but are attracted to magnet as well.

Question 14

What are non-ferrous metals?

Answer 14

These are metals that do not contain iron.
They do not corrode as much compared to ferrous metals and are not attracted to metals.

Question 15

Why is iron a commercially useful material?

Answer 15

It is generally soft and ductile which is commercially useful.

Question 16

If you increase carbon to a material, what happens?

Answer 16

• The metal becomes harder
• Toughness reduces - cast iron is brittle under impact
• Both medium and high carbon steel can be heat treated to make them harder and stronger

Question 17

How to extract aluminium?

Answer 17

Aluminium is extracted from aluminium is extracted aluminium oxide (bauxite) by electrolysis. Electricity passes between the electrodes and pure aluminium forms at the cathode.

Question 18

Properties and uses of aluminium

Answer 18

Non-ferrous
Properties: Lightweight, ductile, malleable, corrosion resistant, electrical and thermal conductor, can be metal inert gas (MIG) and tungsten inert gas (TIG) heat welded.
Melting temperature 660˚C.

Uses: Drinks cans, aircraft bodies, bike frames, window frames, packaging, baking foil

Question 19

Copper properties and uses

Answer 19

Non-ferrous
Properties: Ductile, malleable, tough, corrosion resistant, good electrical and thermal conductor, can be soldered and brazed.
Melting temperature 1,083 ˚C.

Uses: Electrical wire, printed electrical circuits, water pipes, hot water tanks, central heating pipes

Question 20

Zinc properties and uses

Answer 20

Non-ferrous
Properties: Low melting point, good corrosion resistance.
Melting temperature 420 ˚C.

Uses: Galvanising steel as a protective coating for dustbins, buckets, farm gates; intricate die castings

Question 21

Silver properties and uses

Answer 21

Non-ferrous
Properties: Malleable, ductile, corrosion resistant, can be soldered. Melting temperature 962 ˚C.

Uses: Jewellery, cutlery, used for plating other materials

Question 22

Gold properties and uses

Answer 22

Non ferrous
Properties: Malleable, ductile, corrosion resistant, can be soldered. Melting temperature 1,063 ˚C.

Uses: Jewellery, electronic components, connectors, switch components

Question 23

Titanium properties and uses

Answer 23

Non ferrous
Properties: Hard, similar strength to steels but more lightweight, high resistance to corrosion.
Melting temperature 1,668 ˚C.

Uses: Joint replacements, tooth implants, spectacle frames, aircraft, spacecraft, golf clubs, bicycles, ship hulls

Question 24

Tin properties and uses

Answer 24

Non ferrous
Properties: Ductile, malleable, low melting point, corrosion resistant.
Melting temperature 232 ˚C.

Uses: Soft solder, coatings for food cans, rarely used in pure form

Question 25

Low carbon steel properties and uses

Answer 25

Ferrous
Properties: Ductile, high tensile strength, tough, malleable, poor resistance to corrosion.
15–0.30 per cent carbon content.
Melting temperature 1,427 ˚C.

Uses: Nuts, bolts, washers, screws, car bodies, outer panels for white goods

Question 26

Medium carbon steel properties and uses

Answer 26

Ferrous
Properties: Harder than low carbon steel but less ductile, malleable and tough. 30–0.70 per cent carbon content.

Uses: Springs, gardening tools (trowels, forks)

Question 27

Cast iron properties and uses

Answer 27

Ferrous
Properties: Hard outer skin but brittle core, good under compression.
3.5 per cent carbon.
Melting temperature 1,149 ˚C.

Uses: Disc brakes, machine parts, engine blocks; sheet furniture, for example decorative bollards, bins and lighting

Question 28

Stainless steel properties and uses

Answer 28

Ferrous alloys
Properties: Tough, hard, corrosion resistant.
18 per cent chrome, 8 per cent nickel.
Melting temperature 1,510 ˚C.

Uses: Sinks, kitchenware, cutlery

Question 29

High speed steel (HSS) properties and uses

Answer 29

Ferrous alloys
Properties: Hard, tough, high level of resistance to frictional heat. 18 per cent tungsten, 4 per cent chromium, 1 per cent vanadium, 0.5–0.8 per cent carbon.

Uses: Tool blades, drill bits, milling cutters, router bits

Question 30

Die steel properties and uses

Answer 30

Ferrous alloys
Properties: Hard, tough.

Uses: Blanking punches and dies, extruder dies, fine press tool

Question 31

Bronze properties and uses

Answer 31

Non-Ferrous alloys
Properties: Tough, corrosion resistant, can be cast.
90 per cent copper, 10 per cent tin.
Melting temperature 850–1000 °C.

Uses: statues, coins, bearings

Question 32

Brass properties and uses

Answer 32

Non-ferrous alloys
Properties: Corrosion resistant, good electrical and thermal conductor, low melting point, casts well.
65 per cent copper, 35 per cent zinc.
Melting temperature 930 °C.

Uses: Boats fittings, door furniture, cast valves and taps, ornaments

Question 33

Duralumin properties and uses

Answer 33

Non-ferrous alloys
Properties: Equivalent strength properties to low carbon steel but more lightweight, ductile, becomes harder as it is worked.
4 per cent copper, 1 per cent magnesium and manganese

Uses: Aircraft parts, vehicle parts

Question 34

Pewter properties and uses

Answer 34

Non-ferrous alloys
Properties: Malleable, low melting point, casts well.
85–99 per cent tin, with the remainder consisting of copper and antimony.
Melting temperature 170–230 °C.

Uses: Tankards, flasks, goblets, photo frames, decorative items, candlesticks, sports trophies

Question 35

Stock forms of metals

Answer 35

Sheet, Plate, Bar, Tube, Structural

Question 36

Sheet stock form

Answer 36

Sheet is large flat sections of metal in varying thicknesses from less than 1 mm up to approximately 3 mm

Question 37

Plate stock form

Answer 37

Plate is generally thicker than 3 mm and narrower than sheet metals.

Question 38

Bar stock form

Answer 38

Bar is solid form, flat bar, square bar, round bar or hexagonal bar

Question 39

Tube stock form

Answer 39

Tube form is hollow in cross section and can be square, rectangular (also called box section), round or hexagonal.