Ferrous and non-ferrous metals used in fitting, with their properties and uses.
Metals are divided into ferrous (contain iron) and non-ferrous (no iron).
Ferrous metals
Pig iron and cast iron
- Pig iron is produced in the blast furnace from iron ore; it is the raw material for all iron and steel.
- Cast iron has 2 – 4 % carbon. It is brittle, strong in compression, easy to cast and machine, and absorbs vibration.
- Grey cast iron – machine beds, frames, pulleys. White cast iron – very hard. Malleable and SG (nodular) cast iron – tougher.
Steel
| Type | Carbon % | Uses |
|---|---|---|
| Low carbon (mild) steel | up to 0.3 % | Sheets, rods, nuts, bolts, structures – ductile, weldable |
| Medium carbon steel | 0.3 – 0.6 % | Shafts, axles, gears, rails |
| High carbon steel | 0.6 – 1.5 % | Files, chisels, punches, springs, cutting tools – can be hardened |
Alloy steels: stainless steel (chromium + nickel – does not rust), high-speed steel (tungsten, chromium, vanadium – drills, lathe tools).
Non-ferrous metals and alloys
| Metal / alloy | Properties and uses |
|---|---|
| Copper | Reddish, very good conductor, ductile – electrical wires, tubes |
| Aluminium | Light, corrosion resistant, good conductor – utensils, aircraft, cables |
| Zinc | Coating on steel (galvanising) |
| Tin | Coating (tin plate), solder |
| Lead | Heavy, soft – batteries, solder |
| Brass = copper + zinc | Yellow, easily machined – fittings, valves |
| Bronze = copper + tin | Wear resistant – bushes, bearings |
Quick Revision
- Cast iron 2–4 % C – brittle, good in compression.
- Mild steel ≤0.3 % C; high carbon 0.6–1.5 % C (tools).
- Brass = Cu + Zn; Bronze = Cu + Sn.
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