Compared to structural steel, cast iron has what tensile strength?

Compared to structural steel, cast iron has what tensile strength?

• A. Significantly higher tensile strength
• B. Approximately equal tensile strength
• C. Slightly lower tensile strength
• D. Significantly lower tensile strength

Answer: (D)

Cast iron is built to handle compression well but struggles in tension because of its graphite-rich microstructure, which creates crack initiation points. When a tensile load is applied, those cracks propagate quickly and the material welds brittlely rather than deforming plastically. Structural steel, by contrast, is designed for high tensile strength and ductility; its crystal structure and alloying allow it to resist pulling forces much more effectively and to absorb energy by deforming before failure. Because of this fundamental difference, cast iron’s tensile strength is significantly lower than that of structural steel.

Cast iron is built to handle compression well but struggles in tension because of its graphite-rich microstructure, which creates crack initiation points. When a tensile load is applied, those cracks propagate quickly and the material welds brittlely rather than deforming plastically. Structural steel, by contrast, is designed for high tensile strength and ductility; its crystal structure and alloying allow it to resist pulling forces much more effectively and to absorb energy by deforming before failure. Because of this fundamental difference, cast iron’s tensile strength is significantly lower than that of structural steel.