Sisy Wong
Have you ever thought about what kind of military weapons did people use during CA0 to CA1450?
Cast iron is one of the innovations during that period. It is an alloy of iron that contains 2 to 4 percent carbon, also includes silicon, manganese. The process of doing a cast iron is pouring the liquid iron into a thing called “pigs”, the pigs remelted with cupola furnaces and recast into molds, then cooling down its temperature and iron weapons will form. The cast iron first appeared in China in the 6th century BC, then appeared in Europe in the 14th century. Then it introduced to England in 1500. In 1619, James River, Virginia was the place that Americans first established the ironwork. Later in the 18th and 19th centuries, cast iron was cheaper than wrought iron as it was fragile and has worse tensile strength even though it did not require intensive refining and working with hammers. It was the first essential structural metal because of its load-bearing strength and it was used in some earliest tall buildings. Then, in the 20th century, steel replaced cast iron, but it still used in many industrial applications. Cast iron was mostly gray iron or white iron, the color will show up when it fractured. For gray iron, it contains more silicon and it is less hard and more machinable than the white iron. Although both of them are brittle, a malleable cast iron produced by long heat treatment was introduced in France in the 18th century. Also, a cast iron was ductile as cast was invented in the United States and Britain in 1948. Nowadays, the ductile irons were constituted into a major family of metals that are used for gears, dies, automobile crankshafts, and many other machine parts.
Resource: https://www.britannica.com/technology/history-of-technology/China, https://www.britannica.com/technology/cast-iron
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