Iron and Steel

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Mike Fitzpatrick

Construction time again

One of the many advances the new techniques with iron and steel allowed was the construction of different types of bridges and buildings.

Dr. Mike Fitzpatrick

Dr Mike Fitzpatrick is a Senior Lecturer in the Department of Materials Engineering at The Open University. He works on the study of residual stresses in materials, and is an expert on the application of X-ray and neutron diffraction methods for stress measurement. He also researches the development and characterization of high-strength aerospace alloys and composites. He chaired the development and production of the OU’s flagship first-year engineering course (T173) Engineering the Future. Most recently he has co-ordinated a block of material on how engineers design against failure for the new second-level course (T207) The Engineer as Problem Solver, which was launched in 2004.

Related programme

What The Industrial Revolution Did For Us

The Industrial Revolution and the Development of Steel

The Industrial Revolution was characterized by enormous growth in many areas of industry: mining, transport, and construction to name but a few. This growth set up a demand for more raw materials, and in many cases, for new materials with better properties that did not yet exist. As these new materials were developed, by design or by chance, new applications sprang up to make use of them, creating further demands and so on. One of the features of the Industrial Revolution is the plethora of new materials that became available, and the upsurge in manufacturing methods that made use of them. Metals, fibres and even the early precursors of modern plastics were available in unprecedented variety and quantity.

In the 1700s iron was by no means a new material, it had, after all, been around since the Iron Age nearly 3000 years earlier. However, production of iron was restricted to small-scale smelting of iron ores, and the amount that could be produced was limited. Iron was produced by smelting it with charcoal (wood that has been heated in the absence of air to burn off the impurities in the wood and leave it enriched in carbon: this partial burning produces an excellent fuel which is much more effective than wood itself). Britain had depleted huge areas of forest for fuel since the 1500s, and timber supplies for charcoal were not going to be a sustainable long-term solution. Legislation was in place to ban the harvesting of trees for charcoal production.

Charcoal is more than just a heat source for producing iron from its ores. The key step in smelting iron ore to make raw metal is providing a reducing agent as well as heat: a reducing agent is a chemical that reacts with the iron oxides in the ore to release the iron in metallic form. The simplicity of charcoal is that it acts as both the heat source and the reducing agent.

What was needed was a method by which iron could be smelted in serious tonnage quantities. This was going to need a better heat source than charcoal. Woods in Britain were becoming scarce with demands on them for both building timber and charcoal. Coal looked like it might be such a fuel. There was a problem, though: coal tends to have a high concentration of sulphur, which along with other impurities makes iron brittle. So iron produced by smelting with coal was of very poor quality.

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