Traditional wrought iron is an iron alloy that has a low amount of carbon and slag, which creates a supple grain-like material that is highly malleable and easily hammered into shape by blacksmiths. This is where its name comes from—the term “wrought” means worked.
The carbon content of wrought iron is usually less than 0.08%. When heated, this allows the material to be easily extended and shaped, allowing the blacksmith to twist and bend it into intricate patterns to create beautiful balustrades, gates, grilles, and doors. Slag is a by-product of the smelting process, and contains a mix of silicon, aluminium, sulfur, and phosphorus. The slag content of wrought iron makes up about 2% of its weight, and gives the material its fibrous, sinewy look, further adding to its beauty. It also helps to protect it from corrosion.
When wrought iron contains too much sulphur, it is called redshort or hot short, and tends to crack when bent or finished at a red heat. If wrought iron is coldshear or colshire, it has too much phosphorus and can crack when bent.
Wrought iron is made by smelting pure iron ore in a furnace or open hearth. Slag is produced as part of this process, and sits on top of the smelted iron, protecting it from oxidation (although this is a difficult skill that must be mastered by blacksmiths). Once hot, the material can be shaped into the desired product, of which there are many types. You’ll most likely recognise wrought iron from the grand gates or fences of expensive buildings like cathedrals, mansions, palaces, or important public areas. But there’s also wrought iron chairs, benches, tables, beds, doors, artwork, and plenty of other products made from this beautiful material.
Today, the term “wrought iron” has become a catch-all for iron products, many of which are made from other materials such as cast iron or mild steel, and are much easier to work with. These alternative materials are still used to produce incredibly strong, durable, and beautiful wrought iron products, which stand the test of time.
Wrought iron has been used in China for thousands of years but didn’t make its way to Western Europe until the 15th century. It reached its peak in the 1860s, used to create ironclad warships, railways, and the imposing doors and gates that you see in so many European churches, cathedrals, and other significant buildings. It was also used for more commonplace building items like rivets, nails, wire, chains, nuts, and bolts, and everyday items such as horseshoes, and wagon tires. These were traditionally made using a bloomery—a metallurgical furnace made up of a pit, heat-resistant walls, and pipes to allow airflow.
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