Engineering Manufacture - Metals

Ferrous Metals

Metals that contain iron

Examples of ferrous metals

Mild steel

Stainless steel

Cast iron

Non-Ferrous Metals

Metals that do not contain iron

Examples of non-ferrous metals

Copper

Aluminium

Lead

Alloys

A mixtures of two or more metals

Precious Metals

Rare non-ferrous metals

Examples of precious metals

Gold

Silver

Platinum

Alloys

Mixtures of two or more metals and other elements

Examples of alloys

Brass

Bronze

Examples of the aesthetic properties of metal

Colour

Surface texture

Shine

Examples of the functional properties of metal

Cost

Purpose

Weight

Size

Examples of the mechanical properties of metal

strength, plasticity, ductility, hardness, brittleness, malleability.

Examples of the forms metals comes in

Bar

Sheet

Which metals are (usually) magnetic?

Ferrous metals

Rusting

The corrosion of ferrous metals

Which metals are generally not magnetic?

Non-ferrous metals

What happens to non-ferrous metals left exposed to the air?

Oxidation

Oxidation

A layer formed on the surface of a non-ferrous metal

Properties of cast iron

Good compressive strength, hard, more brittle than other ferrous metals, poor corrosion resistance

Advantages of cast iron

Good for casting, cheap

Disadvantages of cast iron

Difficult to machine, has to be protected

Uses of cast iron

Anvils, engineering vices, engine blocks, machine tool beds

Properties of low carbon steel

Ductile, malleable, tough, lower strength than other steels

Advantages of low carbon steel

Stronger than most non-ferrous materials, relatively low cost

Disadvantages of low carbon steel

Cannot be hardened

Uses of low carbon steel

Nails and screws, nuts and bolts, car bodies

Properties of high carbon steel

Strong, hard

Advantages of high carbon steel

Can be hardened

Disadvantages of high carbon steel

Not as tough as lower carbon steel, difficult to form

Uses of high carbon steel

Tools (saw blades, hammers, chisels)

Properties of aluminium

Lightweight, heat and electricity conductor,

ductile, malleable and good resistance to corrosion

Advantages of aluminium

Lower density than steel, easily drawn and cast, recyclable.

Disadvantages of aluminium

More expensive than steel but not as strong and difficult to weld

Uses of aluminium

Drinks cans, aircraft panels

Properties of copper

Good conductor of electricity, good corrosion resistance, malleable and ductile

Advantages of copper

Easily drawn into thin wires and sheets, can be recycled and easily soldered

Disadvantages of copper

Expensive, will tarnish/change colour over time

Uses of copper

Wires, water pipes, jewellery

Properties of tin

Easy to melt, soft, low toxicity level, high corrosion resistance, malleable

Advantages of tin

Non toxic, corrosion resistant, low melting point

Disadvantages of tin

Soft (so usually alloyed)

Uses of tin

Solder, tin can plating

Properties of zinc

Low melting point, heat conductor, corrosion resistant

Advantages of zinc

Good for die-casting

Disadvantages of zinc

Brittle

Uses of zinc

Street lamp posts, motorway safety barriers.

Properties of brass

Good corrosion resistance, casts well, good conductor of heat and electricity, alloy of copper and zinc

Advantages of brass

Can be machined to a high finish

Disadvantages of brass

Difficult to cast

Uses of brass

Doorknobs, musical instruments

Properties of stainless steel

Strong, hard, good corrosion resistance

Disadvantages of stainless steel

Difficult to machine, relatively expensive

Advantages of stainless steel

Doesn't rust

Uses of stainless steel

Cutlery, medical equipment, sinks

Properties of high speed steel

High hardness, high wear resistance and high heat resistance

Advantages of high speed steel

Retains hardness at high temperatures, resistant to friction.

Disadvantages of high speed steel

Can only be ground

Uses of high speed steel

Tools to be used at high speeds

Common uses of silver

Jewellery, silverware, in electronics, brazing alloys, photography

Properties of titanium

Corrosion resistant, low density, very strong

Advantages of titanium

Corrosion resistant, high strength to weight ratio

Disadvantages of titanium

Expensive

Uses of titanium

fighter aircraft, artificial hip joints, pipes in nuclear power stations

Properties of bronze

Hardness: resistance to scratching and wear,

Tough: resistance to breaking or bending,

Corrosion resistant.

Advantages of bronze

Corrosion resistant, easy cast, recyclable.

Disadvantages of bronze

Expensive

Uses of bronze

Bearing, statues,

Air, water & steam valves,

Coins.

Boat propellers

Are metals sustainable?

Metals are a non-renewable resource, but can be recycled well

Is steel sustainable?

Steel is infinitely recyclable, easily recyclable due to its magnetic properties, durable and strong (so long lasting), needs little maintenance to protect from corrosion

Is copper sustainable?

Copper can be difficult to recycle (due to its usage in small amounts in electronics etc), extraction has a high environmental toll, but has high conductivity so efficient when used for wiring

Common Shapes of metals

Round Bar

Square Bar

Hexagonal Bar

Strip

Angle Iron

Square Tube

Round Bar / Rod

Solid round shape

Angle Iron

Piece of strap steel bent into 90 degree angle with holes in it for attaching as a brace.

Hexagonal Bar / Rod

Solid hexagonal shape

Tube

A piece of bar with a hole along its length

Square Tube

Round Tube

Strip Metal

Metal Powder