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  • Writer's pictureNathan Merrill

Why Wrought Iron is Confussed with Decorative Steel Railing, Gates, and Fences.

Before the development of effective methods of steel making and the availability of large quantities of steel, wrought iron was the most common form of malleable iron. It was given the name "wrought" because it was hammered, rolled, or otherwise worked while hot enough to expel molten slag. The modern functional equivalent of wrought iron is mild steel, also called low-carbon steel.

Wrought iron is highly refined, with a small amount of silicate slag forged out into fibres. It comprises around 99.4% iron by mass. The presence of slag can be beneficial for blacksmithing operations, such as forge welding. The silicate inclusions act as a flux and give the material its unique fibrous structure. The silicate filaments in the slag also protect the iron from corrosion and diminish the effect of fatigue caused by shock and vibration.

Wrought iron is no longer produced on a commercial scale. Many products described as wrought iron, such as railings, gates, furniture and lighting are made of mild steel. They retain that description, because they are made to resemble objects which in the past were wrought iron forged by a blacksmith, Many decorative iron objects including fences and gates, were often cast rather than wrought.

Steel was produced in bloomery furnaces for thousands of years, but its large-scale, industrial use began only after more efficient production methods were devised in the 17th century. This was due to the introduction of the blast furnace and production of crucible steel. This was followed by the open-hearth furnace and then the Bessemer process in England in the mid-19th century. With the invention of the Bessemer process, a new era of mass produced steel began. Mild steel replaced wrought iron.

The last ironworks ceased production of wrought iron in the 1970's. Wrought iron is no longer produced on a commercial scale, but is still made for replication, restoration and conservation of historical ironwork. Many products today described as wrought iron are actually made of mild steel. Picture is of the old method of casting iron at the Mabel blast furnace in Sharpsville, Pennsylvania, c. 1915.

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