Steel is an Allomantic metal and an alloy of Iron. When burnt, Steel allows the user to telekinetically push against a metal object, presumably propelling that object in the opposite direction. Normal laws of physics still apply here, so if you push against an object that ways more, you will expend more energy to make it move less. If you push against an object similar in weight to you, you may move as well, and if an object is considerably heavier than you, you will be pushed away from it. As a result, many allomancers use steel to allow themselves to fly through the air. A common use is to drop a coin on the ground, and then push on it. Because it is against the ground which will weigh considerably more than the Allomancer, the allomancer will fly through the air. Allomancers also push on coins to use them as a projectile weapon. Other uses for steel include pushing upon a person that possesses a metal object, or disarming a person with a metal weapon. Any misting only capable of burning steel is known as a coinshot.
When used in Feruchemy, steel allows the user to store physical speed. In exchange for being slower now, they will be faster in the future.