DT GCSE Metals (Section B)

Describe how metals are processed

Describe how metals are processed

The metal is extracted from the ground. It is then crushed and heated with other materials in a blast furnace. This process separates the metal from the ore. The molten metal is poured into a casting machine. It is cooled and run through rollers, to make blocks.

How can using metal impact the environment

1. Metal is non-renewable

2. Extraction of metal ore from the ground can scar the landscape

3. The separation of metals from ores uses vast amounts of energy

4. The separation of metals from ores pollutes the atmosphere

5. The manufacture of metals uses vast amounts of energy

6. Pollution of the atmosphere leads to global warming

7. Metals are often disposed of in landfill sites (more metal will need to be extracted)

Why do we recycle metals

1. Recycling uses less energy than extracting new metal

2. Materials can be reused for different products

3. Metal ores are a finite resource

How can the properties of pure metals be improved

By adding other materials

Give four examples of pure metals that are used in workshops

Aluminium, Copper, Silver and Iron

Name two issues with pure metals

They are expensive and have poor working properties

What is an alloy

A metal (parent metal) combined with other substances (alloying agents), resulting in superior properties

Give an example of an alloy and its component materials

Steel- Iron (parent) and Carbon (alloying agent)

What are ferrous metals

Metals that contain iron

Name one disadvantage of ferrous metals

Because they contain iron, they can rust if they are exposed to moisture

Name a common property of ferrous metals

They are magnetic

How can ferrous metals be made 'harder'

By adding either Chromium, Tungsten or Nickel

Give four examples of ferrous metals

Mild steel, high-carbon steel, stainless steel and cast iron

Name the properties of mild steel

Quite strong, cheap, rusts easily, can't be hardened/tempered, ductile and malleable

Name some uses of mild steel

Car bodies, screws, nuts, bolts, nails, washing machines

Name the properties of high-carbon steel

Harder than mild steel, can be hardened/tempered, hard to work, rusts, poor tensile strength

Name some uses of high-carbon steel

Drills, files, chisels, saws

Name the properties of stainless steel

Hard, won't rust, more expensive, resists wear and corrosion, aesthetically pleasing

Name some uses of stainless steel

Medical equipment, sinks, kettles, cutlery

Name the properties of cast iron

Brittle, compressive strength

Name some uses of cast iron

Manhole covers, vices, brake discs, heavy machine parts

If a metal is non-ferrous, what does it not contain

Iron

Give five examples of non-ferrous metals

Aluminium, brass, copper, lead and duralumin

Name the properties of aluminium

Lightweight, corrosion-resistant, expensive, not as strong as steel, ductile, difficult to join, good conductor of heat and electricity

Name some uses of aluminium

Aeroplanes, cans, ladders, drinks cans, kitchen equipment

Name the properties of brass

Quite strong, corrosion-resistant, malleable, ductile, aesthetically pleasing, good conductor of heat and electricity, casts well

Name some uses of brass

Door handles, electrical parts, kitchen equipment, musical instruments

Name the properties of copper

Relatively soft, malleable, ductile, very good conductor of heat and electricity, corrosion-resistant, polishes well

Name some uses of copper

Central heating systems, plumbing, wiring, pipes, PCB's

Name the properties of lead

Pure metal, heavy, soft, ductile, malleable, environmentally unfriendly

Name some uses of lead

Roofing, medical x-ray vests

Name the properties of duralumin

Almost as strong as mild steel but 30% lighter

Name some uses of duralumin

Fighter jets, bicycle frames

What are the three types of heat treatment

Annealing, hardening, tempering

Describe the process of annealing

A metal is heated to a certain temperature or colour and then allowed to cool slowly

What does annealing achieve

It makes the metal softer, more ductile and less brittle

Describe the process of hardening

A metal is heated and then rapidly cooled (usually by quenching in hot water)

What does hardening achieve

It makes the metal harder but brittle

Describe the process of tempering

The metal is cleaned and then heated carefully until it reaches a certain colour

What does tempering achieve

It makes the metal tougher

What are the four ways of metal surface finishes

Painting, plastic coating, polishing and lacquering