What is the ruling on using industrial oils that contain pork fat in their components for manufacturing iron?

Pig fat is impure (najis) by scholarly consensus. It is permissible to use it for purposes other than consumption, such as for lighting (as fuel for lamps) or for coating leather and ships, while its sale and purchase remain prohibited because it is not considered lawful property (mal shar'i). However, if the properties of pig fat change through transformation (istihala) or consumption (istihlak), such that it no longer exhibits any smell, color, or taste, then its sale and utilization become permissible at that point.