Usually fire, ground, and fighting. Although if you are fighting some Pokemon mixed with steel (ex. Skarmory), ground is not effective because he his half Flying type.
Fire, ground, and fighting.
pyruss/fire Fire, fighting, and ground is good against steel.
Fire and fighting type moves are super effective against Ice type pokemon.
All you need is a ground type pokemon or a ground type move
poison types are good against grass but they are bad against psychic and ground types and also they do no damage against steel so thats why I dont use them unless they have another type.
metal beats rock and many types of moves arent very effective on it
Good against steel Pokemon are fire and water Pokemon.
Fire types are good against Steel,Ice,Bug,and Grass Pokemon.
pyruss/fire Fire, fighting, and ground is good against steel.
Rock beat Ice types also Steel, Fire and Fighting types.
Fire and fighting type moves are super effective against Ice type pokemon.
Fire type moves are good against a pure Steel type. Steelix or Bastiodon, however, have types the negate this, so I suggest Fighting types because this is super effective against both of their types.
Fighting, Fire, Rock and Steel types are good against Ice
fire
Ice and Rock Pokemon
All you need is a ground type pokemon or a ground type move
poison types are good against grass but they are bad against psychic and ground types and also they do no damage against steel so thats why I dont use them unless they have another type.
you will need a good level pokemon but your types can be either water,fire or ground. and fight The best pokemon against steel type is fire type pokemon......train your fire type pokemon to high level before you fight with the gym ....