1.3 Metals

What are the three main categories of metals?

Ferrous metals, Non-ferrous metals, and Alloys.

What is a ferrous metal?

A metal that contains iron.

What is a non-ferrous metal?

A metal that does not contain iron.

What is an alloy?

A combination of different metals to enhance their properties.

Name examples of ferrous metals?

Pig Iron, Cast Iron, Medium Carbon Steel, High Carbon Steel, Mild Steel, Stainless Steel

Name some examples of non-ferrous metals.

Aluminium, Copper, Zinc, Titanium, Silver, and Gold, tin

What are the bondings in metal and how does it add to its characterisitc

Metals have good strength in both compression and tension, due to the very strong metallic bonds holding the atoms together.

What is the primary characteristic of metals that allows metals to conduct heat and electricity?

The presence of free electrons which carry charge around the material

Where do all metals come from?

All metals are extracted from Ores which are found in the earth. Because of this they are considered a finite material (one which will eventually run out.)

Why do ores need to be processed?

Ores must be processed to separate the metal from other minerals, rocks, and soil.

How are ores processed

Steel is derived from Iron Ore which is one of the easiest to separate from its ore using a blast furnace to melt the ore leaving the waste (slag) to float to the top

What percentage of the Earth's crust is made up of metal ores?

25%.

Which metal is the most common in the Earth's crust?

Aluminium (from the ore Bauxite).

Which metal is the only metal that can be used without being processed?

Gold

What is Pig Iron?

A very high carbon iron. Contains 3.5-4.5% carbon. Therefore this makes pig iron brittle and not useful as a building material

What is cast iron?

Pig Iron that has been liquefied and poured into a mould

Has up to 3.5% carbon

It is brittle unless it is heat treated to make it malleable

What are applications of cast iron

Cast iron is used to make anvils and cast engine casings.

Why is carbon added to iron

to make iron stronger. As the carbon amount is increased so too are the hardness properties of the Steel.

What is the carbon content of Mild Steel and what are its properties

0.15 to 0.3% carbon.

ductile, high tensile strength

What are the applications of mild steel

chair legs, bolts, car bodies, casing on a fridge

What is the carbon content of Medium Carbon Steel and what are its properties?

0.3-0.7% Carbon

Harder than mild steel but less ductile

What is Medium Carbon Steel used for?

Springs and general gardening tools; also referred to as Tool Steel.

What is the carbon content of High Carbon Steel

0.7-1.7% Carbon

Application of High Carbon Steel

is used for tools, cutting and drilling parts, blades

What is a major disadvantage of using iron?

It oxidizes. Iron and Steel will oxidise quickly forming a layer of iron oxide which can easily be brushed away and prevented by coating in a layer of oil.

What will happen if iron oxide is left untreated

If left untreated the oxide will begin to erode the surface of the metal and, although it can still be removed, it will leave noticeable marks in the metal.

Eventually the oxide, or rust, will erode the metal away completely to an orange/brown powder.

What happens to iron when small amounts of carbon are added?

It becomes stronger and is classified as Steel.

What is Wrought Iron?

Iron with 0.04-0.08% carbon, traditionally used before the introduction of steel.

What is the role of a blast furnace in metal production?

It is used to melt iron ore, separating the metal from waste (slag).

What is rust?

Rust is iron oxide, formed when iron oxidizes.

What defines non-ferrous metals?

Non-ferrous metals contain no iron and therefore do not rust.

Name three precious/native non-ferrous metals.

Gold, Silver, and Platinum.

Why is aluminum often more expensive than steel?

The processing of bauxite into aluminum is energy-intensive, making it 3-4 times more expensive than steel.

Properties of aluminium

Aluminium has a good strength to weight ratio. This means that given its relatively light weight it is also quite strong, excellent corrosion resistance and good thermal and good thermal and electric coductivity

Applications of aluminium

Aluminium is often used to replace steel in outdoor applications and, due to being lightweight, is also used for portability in sports and camping applications. It is also an excellent conductor of heat so it is used in cooking and for heat sinks and electrical casings to help dissipate the heat.

At what temperature does aluminium melt at

It melts at 660 degrees C

What is the strength to weight ratio of aluminum compared to steel?

Aluminium is a third the weight of steel but roughly half as strong.

Properties of Copper

Ductile, malleable, tough, corrosion resistant, can be soldered

What is copper primarily used for?

Electrical circuits, plumbing, and data cables due to its excellent conductivity.

At what temperature does copper melt?

1083 degrees Celsius.

Applications of tin

food wrapping and coating for steel plate

At what temperature does tin melt?

232 degrees Celsius.

What is lead known for in terms of properties?

Lead is soft, heavy, and has excellent chemical resistance and can block a variety of wavelengths from passing through such as X rays

What are common applications of lead?

Lining containers for radioactive materials and flashing in buildings.

At what temperature does lead melt?

330 degrees Celsius.

Properties of Zinc

Low melting point, good corrosion resistance, highly reactive

What is the primary use of zinc?

Coating steel to prevent rusting, known as galvanizing.

At what temperature does zinc melt?

419 degrees Celsius.

What is titanium's notable property?

It has the highest strength to weight ratio of all metals. It is a very clean material making it suitable for medical and surgical applications

What are common applications of titanium?

Medical and surgical applications, high-performance sports equipment, and spectacle frames.

At what temperature does titanium melt?

1675 degrees Celsius.

What are the melting points of silver, gold, and platinum?

Silver: 960 degrees C, Gold: 1063 degrees C, Platinum: 1755 degrees C.

Properties of tin

Ductile, malleable, low melting point, corrosion resistant

What are the different stock forms of metal?

Sheet, plate

Bar: Flat, round, Square and hexagonal

tube: round, Square, rectangular, hexagonal

structural: H beam, L beam, tee, channel, angle