Heavy metals

Metals and alloys with densities above 4.5 g/cm³ (e.g. copper, zinc and lead) are generally referred to as heavy metals.

Lead
Bronze
Stainless steel
Chrome steel
Copper
Brass
Molybdenum
Nickel
Tungsten
Zinc
Tin

Nickel

is a coloured, lustrous metal that can sometimes have a yellowish tinge. It is one of the few metals that are magnetic. It is acid and heat resistant, and is used to make stainless steel.

Copper

This widely used, reddish-orange metal is an excellent electrical conductor.

Copper overhead conductors

Copper overhead conductors are overhead power lines or cables. They are mostly oxidised, which turns them green, and 4–6 mm thick.

Copper swarf

Copper swarf arises from copper turning and milling. It is bare metal, and is not oxidised.

Enamelled copper wire

Enamelled copper wire includes winding wire for coils, pull solenoids, relay coils and transformers.

Old copper

Old copper means used and oxidised or tarnished copper parts. It is also known as “collected copper”.

Bare copper

Bare copper is new, non-oxidised copper sheet without soldered connections.

Granulated pure copper

Granulated pure copper is the end product when insulated copper cables are recycled.

Brass

This golden-yellow material is an alloy of copper and zinc. It is corrosion resistant.

Heavy and old brass

Heavy brass and old brass are the names given to chrome-plated sanitary fittings and other used brass parts.

New brass

New brass is the collective term for a group of alloys that mainly consist of copper and zinc. The colour of brass depends on the zinc content, and mostly varies between a lighter yellow and a darker one closer to natural gold. With zinc contents below 20% the colour ranges from brownish to brownish-red, and with contents above 36% it is bright to light yellow.

Brass cartridge cases

Brass cartridge cases may be nickel plated, and may even turn out to be made of iron, instead.

Stainless steel

This is a dull silver coloured alloy of iron, chromium and nickel. It is corrosion and acid resistant. It is very tough, and as a result it is hard to work. There are a variety of stainless steel grades. The most widespread grade is 18/8 (18% chrome, 8% nickel and the rest iron), also known as V2A steel. The material number helps us to determine the precise characteristics of the steel.

18/8 stainless steel swarf

18/8 stainless steel swarf comes from turning of 18/8 stainless steel (18% chrome, 8% nickel and the rest iron). Machining may result in the swarf becoming slightly magnetised.

Lead

is a dark-grey heavy metal. It is very soft and malleable.

Lead dross

Lead dross is a by-product of lead casting. The dross floats on the surface of the molten metal, together with impurities.

Lead wheel weights

Lead wheel weights with iron clips are used to balance tyres.

Hard lead

Hard lead has a light ring if you drop – unlike soft lead, which makes a dull thud. Antimony is used as an alloying element.

Tin

is a soft material with a colour ranging from light-grey to white. Uses include the production of bronze.

Tungsten

It is employed as an alloying element for the steel from which industrial drill bits are made, and in light filaments. It is very heavy, and is heat resistant up to 3,400° C (hence its use for light filaments, electrodes and contacts).

Zinc

is a highly lustrous silver-grey, blue-tinged, material. It is chiefly used for iron surface treatment, and to produce brass.

Molybdenum

is a light-grey, lustrous material that is used as an alloying agent for V4A stainless steel. It makes the steel very hard, and corrosion and heat resistant.

Chrome steel

is an alloy of chromium and iron (with no nickel). It is silver coloured and lustrous. Chrome steel is magnetic.

Bronze

This is an alloy of copper and tin. Its colour ranges from orange-brown to light brown with an orange tinge. Bronze is corrosion resistant and has good mechanical properties.

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