Ductile iron is obtained by adding magnesium to the grey iron melt. A chemical reaction forms the free carbon into nodules, which makes this alloy a lot stronger than grey iron (especially in tension due to the enhanced elastic limit). It can therefore withstand larger forces.
Thanks to these improved properties, a lot of steel cast components were replaced by ductile iron in the automotive industry and in agricultural machines. Of course, other industrial applications followed.
Quality ratings are EN-GJS-400-15, -500-7, and -600-3.
If corrosion resistance is required and stainless steel is not viable, the Ni-Resist option can be selected. This is a sort of ductile iron to which nickel and chromium are added. It gives a kind of ‘stainless iron’.