The process of casting ductile iron is not much different from that of other cast irons. First, the iron water that meets the requirements (ductile iron has different grades and mechanical performance requirements) is melted. Then, a deoxidizer is added (in China, rare earth silicon-magnesium alloy, grade 5-8 is usually used; other grades are also used). The amount of the deoxidizer is determined according to the composition of the iron water, the amount of iron water, and production experience. Then, after removing the deoxidizer, a reductant is added (usually 75 silicon iron, the amount is similar to that of the deoxidizer). Mix evenly, then pour the casting. Generally, the deoxidized iron water must be poured within 15 minutes; otherwise, it will cause the deoxidation to deteriorate (deoxidizers containing calcium, barium, and strontium can delay the deterioration to a certain extent). There are many methods for adding deoxidizers and reductants, and each manufacturer has their own habits. There are methods of adding them in the furnace, in the chute, at the bottom of the mold, in the mold cavity, etc. The methods vary greatly and each has its own way.

If qualified ductile iron products cannot be obtained, the castings can only be scrapped. They can be used as scrap materials to smelt the next castings. However, since the deoxidizers and reductants contain silicon, their silicon content exceeds the standard. Therefore, they can only be added in limited amounts or with scrap steel to dilute the silicon content, etc., for reuse.