90% of worldwide metal production can be attributed to ferrous metallurgy. In foundries, gray iron is the most commonly cast metal.
The ferrous alloy, steel, is worked outside of a foundry setting and used in construction, industry, and transportation.

Ferrous metals are defined as those metals which contain iron. Non-ferrous metals contain no trace of iron.

Ferrous and Non-Ferrous Metals | Metal Casting Blog (reliance-foundry.com)