My large modern Collins dictionary definition of wrought iron is ” a pure form of iron having a low carbon content: often used for decorative work.”
I suppose that a dictionary doesn’t set out to tell the full story, but, particularly as modern usage of the term can vary so much from the original and ‘correct’ meaning I feel it is worth attempting to expand upon the point. My apologies to Messrs Collins et al for the presumption.
‘Wrought’, with the meaning of ‘worked’, refers to the ancient methods of making usable iron, in which the initial ‘bloom’ of iron is repeatedly hammered (wrought) during the processes of manufacture.
In addition to this original meaning there is also room for the word ‘wrought’ to apply to the fact that the iron has been worked with the hammer (wrought) by the smith in the course of turning the iron bars and sections as purchased from the foundry into decorative and functional objects – gates, railings, hinges etc.
The process of casting was initially developed to produce ‘pig iron’ and was part of the drive to accelerate and improve the process of creating usable (wrought) iron for the smith. The realisation that it was actually a viable process in its own right for the production of certain goods that the skills of the smith were not so well suited for, (initially canon, firebacks and headstones) was to be an important factor in the industrial revolution and, as it turned out, a large nail in the coffin of the material it was originally intended to promote.
As the use of cast iron as a material became more common, and the objects produced more diverse, ‘wrought iron’ would probably have begun to be the term used to differentiate wrought iron, the material used by the blacksmith, from ‘cast iron’ – a material which owing to the hardness and associated brittleness imparted to it by its’ high carbon content, cannot be wrought successfully beyond the forms it has been cast into when in its’ molten state.
Until the twentieth century these two terms described the differences pretty well. One described iron that was heated to the point of being malleable and wrought into shape by a person with a hammer; the other described iron that was heated to the point of being a liquid and poured into moulds by a person with a ladle. These were the two options, as far as the end user was concerned; Ronseal would have been proud of the labelling.
But then came a series of further and massive advances in our understandings of metallurgy and how to produce and manipulate the resultant materials. Our ability to make large quantities of steel – a material which, hitherto, had been the specialist (and erratic)production of cutlers – and of homogenized forms of iron – now known generically as mild steel – rocketed. A couple of world wars did not hinder this.
Necessarily a whole range of welding technologies sprang up to deal with these, and many other, new materials in fast and controllable ways, and as a result the new discipline of fabrication grew to be the mainstream default for the manufacture of most iron goods.
The blacksmith, who had been so very important up to this point, came under powerful economic pressure to adapt to the new situation; many smiths, according to disposition and circumstance, found their livings more easily in the related fields of mechanics, engineering or fabrication. Wrought iron as a material was gradually sidelined and reduced to being a speciality material used in restoration or where the expense could be justified by high status contexts. Unsurprisingly its’ manufacture became less and less viable and, in this country at least, is no longer made as far as I am aware.
However, the term ‘wrought iron’ had by now entered into the language and it was not going to be dropped completely just because the stuff was no longer made. As discussed previously, the expression had grown a second layer of meaning through which it could be used to describe the product of the forge with particular reference to railings, gates screens etc. of an ornamental nature; that the forge where the ironwork was wrought was rarely a forge and more frequently a fab shop was not an obstacle to this sense of the word coming to be its’ main colloquial meaning.
So, while it retains its’ correct and original meaning in the dictionary and within the trade, today, in general usage, ‘wrought iron’ has come to be little more than a loose generic description of all manner of decorative iron work regardless of material or manufacturing method.
To learn about the history and processes of wrought iron the Ironbridge gorge museum in Shropshire is not a bad place to start,