General Contractor Practice Exam

Which material is primarily composed of iron, carbon, and silicon?

1. Steel

2. Cast iron

3. Aluminum

4. Bronze

The correct answer is: Cast iron

The correct answer is cast iron. Cast iron is primarily composed of iron, carbon, and silicon. The carbon content in cast iron typically ranges from 2% to 4%, and silicon generally constitutes about 1% to 3%. This combination of elements gives cast iron its unique properties, such as excellent castability and a desirable balance of strength and brittleness, making it suitable for various applications, including cookware and construction materials. Steel, while it is also primarily composed of iron and carbon, usually contains a lower carbon percentage (up to about 2%). Additionally, steel can include various other alloying elements like manganese or nickel to enhance specific properties. Aluminum is not composed of iron; it is a distinct metal and does not include significant amounts of carbon or silicon in its primary structure. Similarly, bronze is an alloy primarily made of copper and tin and may include other elements, but it does not feature iron as a primary component. Understanding the composition of these materials allows for better selection in construction and manufacturing processes based on desired properties and performance characteristics.