METALSLECTURE#11

FERROUS METALSFerrous metals mostly contain iron.  they have small amounts of other metals or

elements added, to give the required properties.  ferrous metals are magnetic and give little resistance to corrosion.  some examples of the ferrous metals we deal with:

• Vehicle scrap metal

• Demolition site scrap metal

• Metal offcuts from manufacturing industries

NON-FERROUS METALS

Non-ferrous metals do not contain iron, are not magnetic and are usually more resistant to corrosion than ferrous metals. Some examples of non-ferrous metals we deal with are:

• Aluminum & aluminum alloys

• Copper, brass

• Lead, zinc

• Stainless steel

• Electrical cable

USES OF FERROUS METALS

The following are ferrous metals and the kind of uses to which they are usually put:

• MILD STEEL – carbon content of 0.1 to 0.3% and iron content of 99.7 – 99.9%. used for engineering purposes and in general, none specialised metal products.

• CARBON STEEL – carbon content of 0.6 to 1.4% and iron content of 98.6 to 99.4 %.  used to make cutting tools such as drill bits.

• STAINLESS STEEL – made up of iron, nickel and chromium. resists staining and corrosion and is therefore used for the likes of cutlery and surgical instrumentation. see our infographic celebrating 100 years of stainless steel usage in buildings or the different types of stainless steel.

• CAST IRON – carbon 2 – 6% and iron at 94 to 98%. very strong but brittle. used to manufacture items such as engine blocks and manhole covers.

• WROUGHT IRON – composed of almost 100% iron. used to make items such as ornamental gates and fencing. has fallen out of use somewhat.

USES OF NON-FERROUS METALS

These are the non ferrous metals and their uses:

• ALUMINUM – an alloy of aluminum, copper and manganese. very lightweight and easily worked. used in aircraft manufacture, window frames and some kitchen ware.

• COPPER – copper is a natural occurring substance. the fact that it conducts heat and electricity means that it is used for wiring, tubing and pipe work.

• BRASS – a combination of copper and zinc, usually in the proportions of 65% to 35% respectively. is used for ornamental purposes and within electrical fittings.

• SILVER – mainly a natural substance, but mixing with copper creates sterling silver. used for decorative impact in jewellery and ornaments, and also to solder different metals together.

• LEAD – lead is a naturally occurring substance. it is heavy and very soft and is often used in roofing, in batteries and to make pipes.

THE CHARACTERISTICS OF FERROUS METALS

• Ferrous metals include mild steel, carbon steel, stainless steel, cast iron, and wrought iron. These metals are primarily used for their tensile strength and durability, especially mild steel which helps hold up the tallest skyscrapers and the longest bridges in the world. You can also find ferrous metals in housing construction, industrial containers, large-scale piping, automobiles, rails for railroad and transportation, most of tools and hardware you use around the house, and the knives you cook with at home.

• Due to the high amounts of carbon used when creating them, most ferrous metals and alloys are vulnerable to rust when exposed to the elements. While this isn’t true of wrought iron, which is so iron pure that it resists oxidization, or stainless steel, which is protected thanks to its high chromium content, it’s a good rule of thumb that if you see rust, it’s a ferrous metal.

CONTD…

• Most ferrous metals also have magnetic properties, which makes them very useful in the creation of large motors and electrical appliances. The reason you can tack your child’s artwork to the refrigerator with that magnet with the local pizza place’s phone number on it? Ferrous metal.

• Most importantly, ferrous metals make up the most recycled materials in the world. in 2008 alone, 1.3 billion tons of steel were produced, and 500 million tons of that was made from scrap materials. But we’ll get to why that’s important a little later.

THE CHARACTERISTICS OF NON-FERROUS METALS

• Non-ferrous metals include aluminum, brass, copper, nickel, tin, lead, and zinc, as well as precious metals like gold and silver. While non-ferrous metals can provide strength, they are primarily used where their differences from ferrous metals can provide an advantage.

• For instance, non-ferrous metals are much more malleable than ferrous metals. Non-ferrous metals are also much lighter, making them well-suited for use where strength is needed, but weight is a factor, such as in the aircraft or canning industries. Because they contain no iron, non-ferrous metals have a higher resistance to rust and corrosion, which is why you’ll find these materials in use for gutters, water pipes, roofing, and road signs. Finally, they are also non-magnetic, which makes them perfect for use in small electronics and as electrical wiring.

MILD STEEL

• Ductile & malleable• More tough and more elastic than cast iron and wrought iron• More prone to rusting than wrought iron• Corrodes quickly• Easily forged, welded & riveted• Withstands shocks & impacts well• Not much affected by saline water• Equally strong in tension, compression and in shear• Difficult to harden and temper• Sp. gravity 7.8

MILD STEEL IN BUILDINGS

• Used as rolled structural sections like i-section; t-section; channel section; angle irons. plates round and square rods

• Mild steel round bars

• Used as reinforcement in r.c.c.

• Mild steel tubes are used in structures

• Plain and corrugated mild steel sheets are used in roofing

ASSIGNMENT

• Composition and uses of aluminum in buildings