Wrought iron is one of the most common metal materials used due to the properties it offers. The metal material is tough and malleable, which is why it is suitable for metalworking processes like forging and rolling.
The term wrought means the ability to be hammered, rolled, or otherwise worked while hot enough to expel molten slag. Wrought iron is obtained from puddling pig iron while it is molten. This metal is nearly pure but contains slag in the form of filaments. In this reading, we’ll explore what wrought iron is, its applications, properties, and how it is produced. We’ll also explore the advantages and disadvantages of wrought iron.
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What is Wrought Iron?
Wrought iron is a ductile, soft, fibrous variety produced from a semifused mass of a pure iron globule partially surrounded by slag of about 1 or 2 percent and less than 0.1 percent carbon. Wrought iron is formed from repeatedly heating cast iron. This process gives wrought iron its laminar structure, making it a costly material. It has a far higher tensile strength and is more ductile than cast iron.
Instead of pure iron, engineers use wrought iron to protect against rust. This is because wrought iron has a higher carbon content than pure iron, and with carbon, it naturally protect against rusting. Although, Wrought iron, cast iron, and pure iron will definitely rust when exposed to moisture or air.
Wrought Iron Applications
Wrought iron was known to be widely used during the 19th century in the construction of buildings but was replaced in the 20th century with steel. Then steel was widely available. Wrought iron is highly used for decorative items like fences, gates, railings, balconies, porches, canopies, roof cresting, grilles, hardware, nails, iron cramps, lamps, structural members in tension (I, H, and other beams), etc.
Because of the above items, wrought iron is used in areas such as building construction, woodwork, metalwork, automobiles, and aerospace. They are used to produce items such as table bases, curtain rods, candle holders, etc. in a decorative form. Finally, wrought iron is used to produce bolts, nuts, rivets, crane hooks, chains, and pipes.
The distinctive, fibrous structure of wrought iron, a highly refined material with a small amount of silicate slag, helps in blacksmithing activities and keeps the iron from corrosion. Steel was formerly made from a little quantity of wrought iron and was primarily used for swords, cutlery, chisels, axes, springs, and files. The 1860s experienced the height of wrought iron demand due to the usage of railroads and ironclad warships.
However, wrought iron consumption decreased as qualities improved with the Siemens-Martin and Bessemer processes. Wrought iron was employed in many different products before it became popularity, including wagon tires, straps for wood roof trusses, nuts, bolts, horseshoes, handrails, rails, railway couplings, and artistic ironwork. Although wrought iron is no longer produced commercially, mild steel is still used to make a variety of goods, including gates, garden furniture, and guard rails.
Properties of wrought iron
Wrought iron is an iron obtained from smelting pig iron with a very low carbon content of not less than 0.08. It is tough, malleable, ductile, corrosion-resistant, and can be easily welded. It is fatigue-resistant because of its toughness, and it contains less carbon than cast iron, which makes it softer and more ductile.
As earlier mentioned, wrought iron is highly refined, with a small amount of slag forged into a fiber. It contains 99% iron, making it easily subject to forging, bending, and drawing processes.
How is wrought iron produced?
Wrought iron is produced from cast iron in stages. It consists of very pure iron (0.02–0.05% carbon) and siliceous slag. The stage at which wrought iron was produced from cast iron involved melting and piddling to expose it to oxygen, which oxidized and removed any impurities, such as silicon, carbon, and manganese.
It then cooled until it became a semi-molten, pasty, iron, and slag mixture. Wrought iron is known for its fibrous appearance. It gets stronger whenever it’s worked, and it deforms without failing only when exposed to intense heat (e.g., fire). Well, the video below explains how wrought iron is produced. Learn about Cast Iron here!
Advantages
Below are the benefits of wrought iron:
- Wrought iron is tough
- They have excellent weldability
- High tensile strength
- High compressive strength
- Forged items are easily created.
Disadvantages
- It cannot be hardened by heating and quenching
- It cannot take sudden loads
- Better options are available