Cast iron and ductile iron, like most metals, go through a natural oxidation process, which results in an outer protective coating known as “rust.” This rust layer shields the bulk iron from further oxidation. Think of rust as a corroded armor that protects against additional corrosion.

Can ductile iron corrode?

A: No. Because buried Ductile Iron Pipelines are electrically discontinuous and are essentially grounded for their entire length, underground electrical cables normally do not impose corrosion or safety concerns for Ductile Iron Pipelines.

What's better cast iron or ductile iron?

Ductile iron has excellent corrosion resistance, tensile strength, and yield strength. Unlike cast iron, ductile iron does not break when it is bent, so it is more suited for high demand applications. ... Ductile iron is typically more expensive than cast iron due to its more complicated chemical makeup.