How does the hardness of wrought iron compare to cast iron?

Wrought iron and cast iron are two distinct materials with unique properties, particularly when it comes to hardness. Wrought iron is known for its malleability and ductility, making it softer and more workable than cast iron. This is due to its low carbon content, typically less than 0.08%, which allows it to be easily forged and shaped. In contrast, cast iron contains a higher carbon content, ranging from 2% to 4%, which makes it much harder and more brittle.

The hardness of cast iron is a result of its crystalline structure, which forms during the cooling process. This structure gives cast iron excellent wear resistance and durability, making it ideal for applications requiring high strength and rigidity, such as engine blocks and machine frames. However, its brittleness can be a drawback in situations where flexibility is needed.

On the other hand, wrought iron's lower hardness makes it less suitable for high-stress applications but ideal for decorative and structural purposes, such as gates, railings, and furniture. Its fibrous structure, created by the presence of slag inclusions, provides a unique combination of toughness and corrosion resistance.

In summary, while cast iron is harder and more brittle, wrought iron is softer and more malleable. The choice between the two depends on the specific requirements of the application, balancing hardness, durability, and workability.