Here's my answer! Have a Heatran on your mono Steel team!
Item: Chople Berry/Shuca Berry
Ability: Flash Fire
EV's: 252 SAtk, 120 Def, 120 SDef, 8 HP, 8, Spd
Scary Face/Stealth Rock
Magma Storm/Heat Wave
When a Pokemon with Flash Fire is hit by a Fire-type move, it does not deal damage but instead raises the power of the bearer's Fire-type moves by 50%. A Chople Berry reduce a super effective Fighting type move by 50%. A Shuca Berry reduce a super effective Ground type move by 50%. Earth Power and Stone Edge can counter Fire types, and both moves are pretty powerful. Scary Face can stop Sweepers from sweeping (FireFighting types are normally Sweepers), but Stealth Rock can be very helpful. Magma Storm/Heat Wave are both powerful moves with STAB.
Hope this helped!