The core difference between cast iron and carbon steel lies in their carbon content and the form of carbon present.
Cast iron contains ≥2.11% carbon in the form of graphite, while carbon steel contains 0.02%-2.11% carbon in the form of cementite.
Chemical Composition Differences
Carbon Content Range:
Carbon steel: 0.02%-2.11% (≤2% is the threshold in engineering).
Cast iron: ≥2.11% (mostly 2.5%-4.0% in practical applications).
Other Elements: Cast iron contains 1%-3% silicon to promote graphitization, while carbon steel contains lower levels of elements such as silicon and manganese.
Structural Characteristics
Carbon Form:
Carbon steel: Carbon is dissolved in ferrite or austenite in the form of cementite (Fe3C), forming structures such as pearlite. Cast Iron: Carbon exists primarily as free graphite in the form of flakes, spherical particles, or vermicular graphite, with a small amount present as cementite.
Microstructure: Carbon steel is primarily composed of ferrite and pearlite, while the cast iron matrix contains pearlite but is fragmented by graphite.
Mechanical Property Comparison
Strength and Toughness:
Carbon steel: Strength increases with increasing carbon content. It possesses both good plasticity and toughness, making it suitable for forging.
Cast Iron: Its compressive strength approaches that of carbon steel, but its tensile strength is low and its brittleness is high, making it less able to withstand impact loads.
Special Properties:
Cast iron offers excellent shock absorption, wear resistance, and casting fluidity.
Carbon steel has more uniform thermal conductivity, making it suitable for precision machining.
Of course, if you have casting needs, consider collaborating with Mulan Metal. With 12 years of casting experience, Mulan Metal has helped clients in over 30 countries complete their casting operations and has received widespread recognition. We look forward to hearing from you.
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