Pokémon spawn around you while you wander around the real-world and have the Pokémon Go application running. These random Pokémon vary in type, and some are more likely to show up depending on your location in the real world. For example, if you’re traveling in a forest, you might find Grass, Bug, and Rock-types more often than you do Water-types.
For those looking for any Steel-type Pokémon, you might have a bit more trouble than more common Pokémon. You can typically find Steel-types wandering around the middle of some cities, closer to factories or larger event centers. Some players might have better luck checking out nearby any train stations or railroads.
Steel-type Pokémon do come out more often during a particular time of day, so you don’t need to wait for twilight or the end of the day like you might have to for Ghost-types.
There are only a handful of Steel-type Pokémon in the game, which makes them a bit more challenging to catch. An alternative to directly looking for them in the wild is to visit a PokéStop and place down a Magnetic Lure. The Magnetic Lure will attract Steel, Electric, and Rock-type Pokémon to your location for a set amount of time. It should increase your chances of capturing a Steel-type, but because of the other Pokémon it attracts, it’s not a 100 percent guaranteed method.
The more time you spend wandering around a city, your chances increase of locating a Steel-type wandering around a larger building. You can always check the lower right corner of the Pokémon Go application to see if any Steel-types are wandering specific PokéStop locations near you.