Why is cast iron so much heavier than steel?

Perhaps what you're trying to say is that most cast iron products are pretty thick walled when compared to steel products, which then turn out to be much lighter. read more

Cast iron is no heavier than steel on a pure density basis. Anything made out of cast iron rather than steel is heavier because it needs to be much thicker. Cast iron has lower strength and lower ductility than steel and thus in order to be durable needs to be beefy. read more

Best Answer: The word "heavier" refers to the objects weight or, indirectly, its mass. The mass of the object will depend solely upon how much of the substance you have. There is no one answer your question, it would depend entirely on the amount of steel and the amount of Iron in your sample. read more