Since version 9.0.1 all discs including iron discs were removed, hammering is no longer needed.
An Iron disc is one of the base ingredients used for crafting all of the Poké Balls.
|Iron Disc||Iron Ingot|
Iron Discs can be used on an anvil and turned into Iron Bases with a hammer. They can be re-obtained either by continuing to hammer the base or by using the anvil. This process can also be automated by using a mechanical anvil instead of a regular anvil.