Coalbrookdale MUSEUM of IRON and DARBY HOUSES
 In 1707 Abraham Darby patented a method of casting iron pots. Successive generations of the Darby family expanded the output of the Coalbrookdale ironworks to include iron wheels, rails, steam engine cylinders and of course bridges, the most famous being the Iron Bridge itself, erected over the River Severn 1779. During the Victorian period, Coalbrookdale became famous for the production of decorative cast ironwork.
 The Coalbrookdale Museum of Iron site now consists of a number of restored buildings all associated with the influential Coalbrookdale Company. Coalbrookdale Museum of Iron, the Darby Furnace, and the Darby Houses give a real sense of an industrial community which flourished between 1715 and 1900.
Know Your Iron
What makes iron such a useful material is that its properties can be tailored to meet the needs of huge variety of tasks. This was why it was so important to the success of the industrial revolution and remains such a key material in the world economy today. If you look into the history of iron making you will find three main types:
Cast Iron
 Cast iron melts at about 1300 ºC and can be easily shaped by pouring the molten iron into moulds. Cast iron smelted from iron ore in a blast furnace is called pig iron. Cast iron has a crystalline structure and a carbon content of 3-4%. This makes it hard and brittle, weak in tension, but strong in compression - just the material for building cast iron arched bridges!
Wrought Iron
 Wrought iron was the first type of iron to be used by people. It is relatively soft and once heated can be forged into shape by hammering and rolling. Wrought iron has a very low carbon content (around 0.05%) and unlike cast iron it is strong in tension and resistant to shocks. It was the traditional material of the village blacksmith and during the Industrial Revolution its properties made it essential for everything from nuts and bolts to steam engine boilers.
Atlas Forge in Bolton was the last commercial wrought iron works in Britain when it closed in 1974. Some of the equipment from this works has been re-erected at Blists Hill Victorian Town and can occasionally be seen in operation.
Steel
 Steel has a carbon content of 0.25 -.0.4%. This tiny increase in carbon content gives steel the hardness and the ability to hold a sharp edge that wrought iron lacks. Steel has a long history connected with weapon and tool making but was expensive and difficult to make. In 1856 Henry Bessemer discovered a method of mass producing steel. It could be forged into shape by hammering and rolling but unlike wrought iron it could be produced in large quantise cheaply and with less labour. It rapidly replaced wrought iron in most fields of engineering.
Today a wide variety of different steels are made by varying the carbon content and other ingredients. These vary from hard cutting steels for tools to softer steels which can be rolled into thin sheets and pressed out into complex car panels without cracking. The Jackfield Bridge across the Severn near Ironbridge with its steel tower, beams and cables is a good example of what can be built with steel.
 "This huge blowing engine on display at Blists Hill provided the air blast for Bessemer converters at Priorslee Steel Works which were not far from the present day Telford town centre."
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