what are the types of iron? mention it's uses
Answers
Answer:
Iron is used to make alloy steels like carbon steels with additives such as nickel, chromium, vanadium, tungsten, and manganese. These are used to make bridges, electricity pylons, bicycle chains, cutting tools and rifle barrels. Cast iron contains 3–5% carbon. It is used for pipes, valves, and pumps.
answer:
Iron as an element is not in common use. However, the term iron is used for different materials which contain a high percentage of iron in elemental form. These materials are categorized as (i) pure iron, (ii) wrought iron, (iii) cast iron, (iv) pig iron, and (v) direct reduced iron.
Pure iron
Pure iron is a term used to describe new iron produced in an electric arc furnace where temperatures sufficient to melt the iron can be achieved. The result, also known as ‘butter iron’ is typically around 99.8 % pure with a carbon content of around 0.005 % and manganese content of around 0.005 %. There are also traceable amounts of a number of other elements some of which add certain properties or characteristics to the material and others which are of no significance.
Pure Iron, with a minimum Fe content of 99.85 %, without the addition of alloy elements was first developed in 1909 by the former American Rolling Mill Company (ARMCO).
The typical analysis of the commercially produced pure iron is given in Tab 1. The ultimate tensile strength (UTS) of commercially produced pure iron is between 230 N/sq mm to 370 N/sq mm which is similar to that of new high grade wrought iron. There is little difference between the two materials other than the fact that pure iron does not contain any slag or laminations and has superior corrosion resistance.
Wrought iron
Wrought iron is a form of commercial iron which has very low carbon content (less than 0.10 %), less than 0.25 % of impurities consisting of sulphur, phosphorus, silicon and manganese. It is a semi-fused mass of iron with fibrous slag inclusions (up to 2 % by weight) which gives it a ‘grain’ resembling wood, which is visible when it is etched or bent to the point of failure.
Historically, wrought iron was known as ‘commercially pure iron’. However, it no longer qualifies since current standards for commercially pure iron require a carbon content of less than 0.008 %.
Wrought iron is soft, ductile, magnetic, strong with high elasticity and tensile strength, malleable and hence it can be heated and reheated and worked into various shapes, becomes stronger the more it is worked, and suitable for members in tension or compression. It is corrosion-resistant and can be welded. Before the development of effective methods of steelmaking and the availability of large quantities of steel, wrought iron was the most common form of malleable iron. A wrought product is one that has been mechanically worked by forging, extruding, rolling, and hammering etc., to change its form and properties. Wrought iron product is a particular worked iron product which is rarely produced now since other cheaper, superior products have substituted it.
Wrought iron is redshort if it contains sulphur in excess quantity. It has sufficient tenacity when cold, but cracks when bent or finished at a red heat. Wrought iron with high sulphur is therefore useless for welding or forging.
Cast iron
The term ‘cast iron’ represents a large family of ferrous alloys. Cast irons are multi-component ferrous alloys, which solidify with a eutectic. The major elements of cast irons are iron, carbon (2 % or more), silicon (1 % to 3 %), minor elements (less than 0.1 %), and often alloying elements (less than 0.1%). Cast iron has higher carbon and silicon contents than steel. The structure of cast iron displays a richer carbon phase than that of steel because of its higher carbon content. Cast iron can solidify according to the thermodynamically metastable Fe-Fe3C (iron carbide) system or the stable iron-graphite system depending principally on composition, cooling rate, and melt treatment.
The main factors which have influence on the micro structure of the cast iron are (i) chemical composition, (ii) cooling rate, (iii) liquid treatment, and (iv) heat treatment.