Steel
From A Wiki of Ice and Fire

Steel is hard metal, often used to make weapons and armour of war. Iron is the base metal of steel.
Steel is one of the metals used by maesters for their chain links.[1]
The Street of Steel in King's Landing is named after the metal. [2]
References
- ↑ A Game of Thrones, Chapter 41, Jon V.
- ↑ A Game of Thrones, Chapter 27, Eddard VI.