Cast Iron

The earliest known cast iron was produced by the Chinese as far back as the 6th Century BC and it was nearly two thousand years before Europe began to produce it regularly. It is made by heating up iron ore in a very hot furnace; the resulting molten metal is poured into a cast to form a solid ingot known as a 'pig' and then it can be subsequently melted down again and poured into moulds to form different products. The material was hard and durable but brittle initially; advances in metalurgy, most of which were found by trial and error, produced castings which were harder, malleable, or ductile.

The properties of cast iron depend to a large degree upon the impurities that are present, some of which give desirable characteristics and some which are definitely disadvantageous. The other major factor affecting the properties of cast iron are the temperature it is heated to, the length of time it is maintained at that temperature, and the control of the cooling process.

Iron slowly replaced bronze for tools and weopons very slowly because although it is much harder iron requires far higher temperatures to manufacture and work it so it was not until advances in furnace design came about that it's manufacture became practicable; however once the technical difficulties had been mastered it's ascendancy was assured; not only was it a harder and more durable material than bronze but the ore was far more abundant and so far cheaper. It is no exageration to say that the possession of casting skills were of international importance; for instance, from around the 16th to the 18th Century the British cast iron guns and cannons, were so superior to other continental products that many areas of Britain grew comparatively rich by manufacturing armaments for sale to both the crown and foreign countries, notably the Dutch. As a result some historians argue that metalurgy had the greatest impact on world history since the fall of the Roman Empire.