Invented in China during the 5th century BC, cast iron was initially utilised for a variety of purposes, including the crafting of ploughshares, pots, weapons, and pagodas by pouring it into moulds. While steel held greater appeal, cast iron’s affordability made it the more predominant choice for equipment in ancient China, with wrought iron or steel reserved for weaponry.
The Chinese further refined cast iron production through a process known as annealing. This involved subjecting hot castings to an oxidising atmosphere for a week or more, to burn off some surface carbon. This technique helped to prevent the surface layer from becoming excessively brittle.
Historians are divided by the origin, with some arguing that it was discovered by the Egyptians who hammered the metal to mould it to make various tools. It wasn’t until around 2000 BCE that the Hittites of Egypt developed a process for smelting the iron, broadening its uses.
Religion played a significant role in driving forward the advancement and innovation of foundry technology. An incentive for progress came from the construction of cathedrals and churches. As the demand from the dominant Catholic Church increased, the processes of melting and mould-making underwent rapid development to keep pace. This period marked a crucial transition from casting primarily for artistic purposes to recognising casting as a technology with immense potential.
Interestingly, the evolution of bell casting led to a pivotal moment in history. When a monk used the same casting technology to produce the first cannon. This event symbolised a shift towards the use of casting techniques in warfare.
In the western world, cast iron didn’t become widely available until the 15th century. Initially, it was mainly used for making cannons. Henry VIII was one of the early advocates of casting cannon. English ironworkers, using blast furnaces, developed a method for producing cast-iron cannons that were heavier than the existing bronze cannons but much more affordable. This allowed England to bolster its naval power more effectively.
Additionally, cast-iron pots began to be manufactured at numerous English blast furnaces during this time. In 1707, Abraham Darby patented a new method for making pots and kettles thinner, making them cheaper than those made by traditional methods. This led to his furnaces becoming dominant suppliers of pots, a trend that continued into the 1720s and 1730s when a few other coke-fired blast furnaces also joined in the production.
The application of the steam engine to power blast bellows indirectly by pumping water to a waterwheel in Britain, starting in 1743 and increasing in the 1750s, played a significant role in increasing the production of cast iron. This surge in production continued in the following decades, marking a period of significant growth in the cast iron industry.
In the UK, having many purposes from farming tools to weapons of war, blacksmiths were a staple in each town, working with iron to change its properties and shape for different uses.
A blacksmith is a skilled craftsman who works with iron and steel, heating the metals in a forge and shaping them. Traditionally, blacksmiths were responsible for creating a wide range of metal objects, including tools, weapons, horseshoes, and decorative items.
The casting process for cast iron involves melting iron alloys at high temperatures and pouring the molten metal into a mould. This method allows for the creation of intricate shapes and designs, making cast iron ideal for a wide range of applications, from industrial machinery to cookware.
The United States played a crucial role in advancing the production and application of cast iron, notably throughout the 19th and 20th centuries. Through their pioneering efforts, the United States emerged as a global leader in cast iron production, leaving a mark on the industrial landscape of the era.
The Rise of Cast Iron Cookware
One of the most iconic uses of cast iron is in cookware, including pots, pans, and skillets. Cast iron cookware gained popularity in the 19th century for its durability and even heat distribution. Today, cast iron pans are cherished for their ability to retain heat and create the perfect sear.
