Look up Smithing (Skyrim).
You have to increase your smithing to 80 and then have the steel, dwarven and orcish smithing perks.
One less expensive way to bring up your smithing fast is to explore Dwymer ruins and take out any Dwymer struts, plate metal and solid metal. Then use a smelter to turn these into dwarven ingots and use the ingots to create and improve dwarven armor.
Also, completing the Unfathomable Depths quest will give you a power that causes your smithing skill to increase 15% faster.
The most efficient item to smith for leveling using Dwarven metal ingots is the Dwarven bow. They take 2 Dwarven metal ingots and one iron ingot to make. Craft them and then improve them before selling them. (We always ended up with far more than we could sell immediately.)