Below is a list of Ductile Castings manufacturers from Grand Rapids, Michigan. Ductile castings are molded iron components made with a particular group of cast iron alloys that are designed for improved flexibility as compared to traditional grey iron castings that tend to be brittle. Also known as nodular cast iron, this blend of elements includes fractional amounts of magnesium, cerium or yttrium which cause carbon to form in graphitic nodules or spheroids rather than flakes, thus promoting ductility.