In the 21st century, there is a growing concern that the planet is running out of natural resources mainly because of a threat from constantly increased population that begin to consume the natural wealth faster than they can be replenished. However, there are still substantial mineral deposits in the world today to sustain the humanity for a few more generations before formulation of lasting solutions.
Human beings have found various uses for different kinds of metals, including gold, silver, bronze and iron. Among all the above mentioned, iron, however, has been of more value to humanity compared to the rest materials. Human beings use iron since the agrarian era, and with the advent of the industrial revolution, the need for iron has been virtually unlimited (Ozersky, 2012, par. 8).
Throughout the technological development up to date, one of the materials that is the most useful to humanity is called cast iron. Cast iron has been and continues to be important to various industrial processes.
Cast iron is not pure iron because it is mainly made from pig iron which is heated with other scrap metals until it liquefies, then flowed into moulds and solidified (West, 2008, p. 78). Cast iron, therefore, is a ferrous alloy that mainly contains Carbon and Silicon as the main alloying elements.
Cast iron may come in two alloy forms, white and grey. Other forms of cast iron alloys include malleable cast iron and ductile cast iron. Historically, cast iron has many uses including building of bridges, various buildings and textile mills.
This discussion will focus on the process of cast iron production, the uses of this metal and the economic importance that cast iron presents to the places where it is produced. In essence, the discussion will be aiming to put to perspective the relevance of cast iron in today’s technologically fast changing world.
Production of Cast Iron
Cast iron is mainly made through re-melting of pig iron. Pig iron is the main raw material used in the production of cast iron. It is important to note that cast iron mainly describes the grey cast iron that is the commonest of all cast iron varieties (West, 2008, p. 83). In the production process, pig iron is melted along with steel and other scrap iron metals.
After re-melting, the molten cast iron then goes through an impurity removal stage after which it is cast. Casting involves the process of giving shape to cast iron through pouring of the molten cast iron into a mold. Normally, the process includes the stage when sand and metal mold are pouring through a dome with the help of a low pressure vacuum or via gravity.
Casting of the molten metal is followed by solidification which must be done carefully since chances of destruction are high at this stage. Solidification mainly depends on the control of the cooling curves (Berns & Theisen, 2008, p. 154). Quick cooling and slow cooling produce fine and coarse grain construction of cast iron respectively.
After cooling is done, the moulds are broken in a lengthy elaborate process known as fretting that also includes grinding and shot blasting. After this process is done, the finished cast iron is ready for industrial use.
In cases where the cooling may not be appropriate, the destroyed cast iron is recycled back to furnace where it is melted and goes through the whole process again. Additionally, old items made of cast iron make up part of the recycled iron, a property that is quite environmental friendly. The simple diagram below helps put into perspective the process of cast iron production.
Fig 1.0 Production of Cast Iron
Benefits and uses of cast iron
While examining the structure of cast iron, it is important to acknowledge that there are many other materials similar to this material and can perform the same functions. However, it is also important to acknowledge that cast iron has its benefits that make it a unique choice for industrial processes (Gifford, 2007, par. 6).
Some of the advantages of cast iron include availability in a wide range of mechanical and/or physical properties making it versatile in its application in industrial processes and construction. Cast iron also has an excellent strength to weight ratio and costs less compared to other materials that can serve for the same needs as cast iron does (West, 2008, p. 94).
Cast iron also presents its users with a lower density and higher thermal conductivity with exceptional tensile strength levels that many metals do not have. Cast iron has free graphite as one of its components that raises its quality for machine use and makes it conducive for high speeds and feeds. In the case of gray irons, cast iron offers exceptional damping capacity (Campbell, 2008, p. 453).
Perhaps, one of the best properties of cast iron is the easiness with which it can be modified through chemical analysis to provide desired and improved properties including resistance to corrosion oxidation and wear and tear. The metal is also flexible in such a way that designers can easily modify it to suit their need and requirement for sales purposes.
Cast iron has been used for various purposes for a very long period. Since the beginning of its production by ancient Chinese, cast iron’s uses have become more diverse than at the initial stage; now, it ranges from making weapons to making cannons, buildings, cookware and decorative pieces for both individual and home usage (Ozersky, 2012, par. 5).
It is safe to assert that cast iron is increasingly making its comeback to the main fold, especially with development of technologies that can modify it to suit consumers’ tastes and preferences.
Relevance and economic usefulness
Production and use of cast iron fall into multiple industries. Mining, manufacturing and building and construction sectors claim a stake in the cast iron industry (Howell, 1987). Given its excellent properties and the versatility that it presents in industrial process, cast iron comes to the fore as a top choice for consumers in the above mentioned industries.
Its presence in any country or region of the world is bound to be beneficial in terms of revenue generation and easy access to the highly sought material. The advantages that come a long have a ripple effect that resonates from a national or regional level to the people at the grassroots involved in cast iron production. The economic profits include creation of jobs and generation of revenue for the national and local communities involved.
The discussion above hardly examines everything about cast iron. However, there is one clear conclusion that can be made. Cast iron has been central to the development of human’s civilization. Today, cast iron is as important as it used to be centuries ago.
Given that its production does not call for complicated processes as other materials that involve extraction from iron ore, cast iron presents the best opportunities to all parties involved in its production and use.
Disregarding the perspective from which one looks at it, the relevance of cast iron is indisputable. It is a foregone conclusion that cast iron is a crucial component in the industrial process, and only few industries can optimally perform without it.
Berns, H. & Theisen, W. (2008). Ferrous Materials: Steels and Cast Iron. London: Sage publications.
Campbell, F. (2008). Elements of Metallurgy and Engineering Alloys. New York: John Willey & Sons.
Gifford, H. (2007). Copper and Cast Iron. Home Energy Magazine. Retrieved from: http://www.homeenergy.org/show/article/nav/heating/page/2/id/399
Howell, J. (1987). Architectural Cast Iron: Design and Restoration. The Journal of the Association for Preservation Technology, 15(3), 51-55.
Ozersky, J. Monday, (2012 Mar. 26). A Pan for All Seasons. Time Magazine US, 1 – 4.
West, T. (2008). Metallurgy of Cast Iron. New York: Cengage Learning.