Metals

All metals are classified into:

a)      Ferrous metals: Wherein iron is the main
       constituent (Cast iron, wrought iron and
       different forms of steels)

b)     Non-Ferrous metals: Wherein iron is not
       the main constituent (Copper, Aluminum,
       Zinc and lead etc)

c)      Non ferrous alloys: Alloys of copper

 

Ferrous metals are not directly obtained from iron ores.

a)   Ferrous metals

1) PIG IRON:

Pig iron is a metal material that results when iron ore, charcoal from coal, and limestone are melted together under intense air pressure. When the combined material cools, it forms a high-carbon product known as pig iron. Usually, this type of iron is further refined through additional melting and blending processes to create wrought iron, cast iron, or steel.

2) CAST IRON:

Cast iron is another type of alloy that can be refined from the initial material. Cast iron is stronger and less breakable than the initial material, thanks to a process that removes carbon, and other elements while adding desirable characteristics thanks to melted scrap metal and steel. Once popular as bridge and building material, cast iron is also used to create pots and pans that withstand and distribute high heat evenly.

3) WROUGHT IRON

Wrought iron is a soft, easily worked, fibrous metal. It usually contains less than 0.1% carbon. It is superior for most purposes to cast iron, which is hard and brittle because of its higher carbon content.

Since mild steel has replaced the wrought iron, therefore it is no longer produced in large extent.

4) STEEL

Steel is an alloy of iron and carbon. Pure iron’s strength remarkably increases when alloyed with carbon. The tensile strength increases with increasing carbon content but the ductility reduces. Structural steel has a low carbon content.

PLAIN CARBON STEEL can further be classified as:

  1. Low carbon steel or mild steel: iron with up to 0.30% carbon alloyed with it. The bulk of construction steel has  Grade: 300PLUS®,which has replace the Grade 250 MPa       and 350 MPa

  2. Medium-carbon steel :   carbon content is 0.30 to 0.5 % Stronger than the mild steel s but lightly less ductile

  3. High- carbon steel :        carbon content is above 0.5
          Harder and stronger than mild steel and medium carbon steel

Steel products are supplied in accordance with AS/NZS 3678 (Structural steel - hot-rolled plates and floor plates), AS/NZS 1594 (Hot-rolled steel flat products), AS1548 (Steel plates for pressure equipment) and AS/NZS1365 (Tolerances for flat-rolled steel products).

 These specifications cover such matters as testing, inspection, certification procedures and dimensional tolerances.

Structural Sections available comprise:
Solid Angles; Beams; Columns; Welded Beams; & Hollow Section

Hot-Rolled Structurals
Beams, Universal Columns, Angles (Equal & Unequal)
Hot Rolled Structural Steel sections are manufactured in accordance with the requirements of Australian/New Zealand Standard AS/NZS 3679.1 Structural steel – Hot-rolled bars and sections.

Cold-Formed Structurals

Hollow Sections (Square, Rectangular & Circular)

They are high strength cold formed structural sections that are In-line hot-dip galvanized over a prepared metal surface, to produce a fully bonded coating with a minimum average coating mass of 100g/m2, in accordance with AS/NZS 4791:1999 ILG100. The zinc surface then has a surface conversion coating applied. All channels are coated with a clear polymer over the conversion coat.

MANUFACTURE OF STEEL

Three basic raw materials are needed in large quantities for the production of steel

1.   Iron Ore
2.   Coal
3.   Lime stone
The first step in the steel manufacture begins at the blast furnace. To separate iron from iron ore limestone and dolomite are charged into the blast furnace. The product of the blast furnace is known as “Pig Iron” the basic ingredient of steel
Some of the pig iron goes to the foundries to make iron castings, but the vast majority is re melted and used in the production of steel in steel furnace.

b)   Non-Ferrous metals

Non-ferrous metals are metals that do not contain iron. There are two groups of metals; ferrous and non-ferrous. Ferrous metals contain iron, for example carbon steel, stainless steel (both alloys; mixtures of metals) and wrought iron. Non-ferrous metals don't contain iron, for example aluminium, brass, copper (which can be remembered as ABC) and titanium. You can also get non-ferrous metals as alloys eg, brass is an alloy of copper and zinc.

Nonferrous metals are specified for structural applications requiring reduced weight, higher strength, nonmagnetic properties, higher melting points, or resistance to chemical and atmospheric corrosion. They are also specified for electrical and electronic applications.

Non - Ferrous Metals

Aluminum

Copper

Lead

Zinc

Brass

Bronze

Aluminum
Pure aluminum is a silvery-white metal with many desirable characteristics. It is light, nontoxic (as the metal), nonmagnetic and nonsparking. It is easily formed, machined, and cast. Because of aluminum's mechanical and physical properties, it is an extremely convenient and widely used metal.
Uses in Building: Door and window frames wall cladding, roofing, awnings etc.

Copper
Copper provides a diverse range of properties: good thermal and electrical conductivity, corrosion resistance and ease of forming. Next to silver, copper is the next best electrical conductor. It is a yellowish red metal that polishes to a bright metallic luster. It is tough, ductile and malleable.
Copper and its alloys -- the brasses and bronzes -- are available in rod, plate, strip, sheet, tube shapes
Uses in Building: Roofing. plumbing (pipes & fittings), electrical wiring etc

Lead
Lead is the most impervious of all common metals to Xrays and gamma radiation and it resists attack by many corrosive chemicals, most types of soil, and marine and industrial environments. Main reasons for using lead often include, ease of forming, high density, good sound and vibration absorption, and ease of salvaging from scrap.
Uses in Building: Flashing, roofing, damp coursing etc.

Zinc
Zinc is a silvery blue-grey metal .When unalloyed, its strength and hardness is greater than that of tin or lead, but appreciably less than that of aluminium or copper. One of the most useful characteristics of zinc is its resistance to atmospheric corrosion, and just over half of its use is for the protection of steelwork. In addition to its metal and alloy forms, zinc also extends the life of other materials such as steel (by hot dipping or electro-galvanizing). Zinc is also used to make brass, bronze.
Uses: in Building: Roofing, hot dipping, electro-galvanizing, (ZINCALUME® steel) roofing, framing, garage doors, guttering etc.

d)   Non ferrous alloys

These are metals which do not contain any iron. They are not magnetic and are usually more resistant to corrosion than ferrous metals.

Brass
Brass is a metal composed primarily of copper and zinc. Copper is the main component, and brass is usually classified as a copper alloy. Brass is stronger and harder than copper, but not as strong or hard as steel. It is easy to form into various shapes, a good conductor of heat, and generally resistant to corrosion from salt water.
Uses: in Building: plumbing, hose and brass tube fittings

Bronze
It is hard and brittle, and it was particularly significant in olden days, so much so that the Bronze Age was named after the metal. Traditional bronze is a copper alloy with up to 10% tin. The tin in bronze makes it more resistant to wear than unalloyed copper. Bronze parts are typically used for bearings, clips, electrical connectors and sculpture.

Other types of bronze:
Aluminium bronze is a copper-aluminium alloy that may contain iron, nickel, and/or silicon for greater strength. Aluminium bronze is frequently used for aircraft and automobile engine parts.

Manganese bronze, (a brass containing manganese. It is often used for ship propellers because it is strong and resists saltwater corrosion)

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