Ferrous and Non-Ferrous Metals: Properties & Uses

Ferrous Metals

Iron minerals from the Earth's surface undergo different processes to obtain pure iron and its alloys: steel and cast iron.

Percentage of Carbon:

• Pure Iron: The concentration of carbon is between 0.008% and 0.03%.
• Steel: Between 0.03% and 1.76%.
• Cast Iron: Between 1.76% and 6.67%.

Pure Iron

Advantages: Good magnetic properties. Disadvantages: Melts only at high temperatures; difficult to machine. Uses: Electronics and electrical components.

Cast Iron

Properties: Very hard and resistant. Uses: Machine parts, lamps, pistons, drain covers.

Steel

Properties: Very hard and resistant; easy to weld. Uses: Construction, boats, tools, screws, domestic appliances, etc.

Metallurgy

Iron metal is washed to eliminate any impurities. It is crushed and sieved to separate the gangue from the ore. The ore is mixed with coke and limestone, and then put into a blast furnace with temperatures of 1500ºC. Slag is obtained. This is a by-product made up of carbon and other impurities.

Non-Ferrous Metals

Non-ferrous metals are classified as ultra-light, light, or heavy.

Ultra-Light

• Magnesium: Shiny, very light, soft, and malleable.

Light

• Aluminum: Silvery white, highly resistant to corrosion, very soft.
• Titanium: Silvery white, shiny, very hard, and strong.

Heavy

• Copper: Reddish, very shiny, soft, good electrical conductor.
• Brass: Very resistant to corrosion.
• Bronze: Resistant to general wear and corrosion.
• Zinc: Bluish grey, fragile.

Shaping Techniques

To make pieces for sale or for industry, the metal goes through a series of shaping processes.

• Extrusion: The heated metal is pushed through a hole by a piston, using compression.
• Forging:The metal piece is shaped by repeated and continuous compression forces using hammers,tongs or anvils.

Finishing Techniques

• Grinding: A grinder is used to refine surfaces to precise, accurate dimensions and to remove any imperfections.
• Lapping: A lapping machine has a vertical handle and abrasive discs; this is usually used for conical surfaces.
• Polishing: Produces shine using a polishing wheel with revolving.
• Buffing: This technique produces a shine. A mechanical buffing wheel is used with a steel disc or roll.
• Coating: To protect the metal, the metal is coated in plastic or other metals.