The word “wrought” as used in the term “wrought iron” is the former past tense of the verb to work. As with many other irregular past tense verbs in the English language, over time “wrought” was replaced with “worked.” However, the term “wrought iron” still exists today.
Although iron is one of the most abundant metals on Earth, it was very slow to evolve into a commonly used metal because of the difficulty involved originally in working with it. Early iron workers had a difficult time understanding that in order to make it more malleable it was essential to reduce the carbon content by melting the metal again a second time and hammering the ingots to expel the carbon and other impurities. One this was discovered, iron was no longer brittle like cast iron is.
Because of their ability to change the composition of wrought iron using fire and water, blacksmiths were sometimes seen as magical sorcerers and put on the same level as doctors. These men were blessed with having created metals that were unable to break in battle. Vulcan and Hephaestus were the first encounters in Roman and Greek mythology with blacksmiths. It was not until later that artistically worked iron was used in the construction of buildings such as churches and monasteries, with the first recorded use being Notre Dame in Paris and Winchester Cathedral in England.
One of iron’s original production methods was by being smelted using bloomeries. A bloomery is a sort of furnace with a pit and chimney with stone or clay walls for heat resistance. Clay pipes entered near the bottom of the pit to allow airflow either from natural source or through the use of a type of air pump known as a bellow. Once a bloomery was filled with charcoal and iron ore it was lit and air was forced through the pipes to heat the mixture to just below the melting point for iron. The impurities would melt and run off and the carbon monoxide from the charcoal reduced the ore to iron in a sponge like mass. This material was then forged with hammers, which removed impurities in the process.
Later during the Middle Ages, water was used to power the bellows and eventually the hammers, making the job of working iron much easier, but in the 15th century the concept of a blast furnace was created in Europe. However, the iron created in a blast furnace was very brittle and needed to be refined. It would not be until the Industrial Revolution that a process for making durable wrought iron more efficiently was created.
A puddling furnace was invented in 1784 and it is credited at the time with being the most successful way of creating wrought iron without the use of charcoal. In the nineteenth century the demand began for stronger wrought iron, thus bringing to the industry a method to mass-produce puddle iron. This new mass production of wrought iron created a metal with a higher tensile strength and a small increase in carbon content. This made the chemical composition and consistency easier to control then before.
The term “wrought iron” is often used to describe products that are actually made from mild steel nowadays. This is because traditionally made wrought iron is not forged as often anymore. This has given rise to the common conception that mild steel products are “wrought iron” and why the two terms are often used interchangeably. Mild steel is a combination of iron and carbon as well as other elements present in quantities too small to affect the overall properties. The higher the carbon content the harder but less ductile and less easy to weld the steel becomes. Mild steel has the lowest carbon content of between .05% and .26% making it quite easy to work with. Uses today for wrought iron are quite varied and include water pipes, railway couplings, nuts and bolts, as well as decorative ironwork such as handrails, fences and wine racks.
The manufacturing of wrought iron has experienced many changes over the centuries in its process and materials, but the outcome has remained the same, giving while still providing us today with attractive and interesting products constructed from this sturdy material.