Gym Team

I'm making a steel gym for another site. Can i have some help deciding pokemon?

This isn't really the place to ask that (as this isn't a RMT thread), but here goes!

What are the rules? Do all six have to be steel type or can you have a non-steel?

I'd HIGHLY recommend Heatran and Lucario, first off. Both are basically needed on a steel team, haha! I'd also use one of the Steel/Psychic types (Jirachi, Bronzong, and Metagross). Skarmory covers your ground weakness and is another nice choice. Scizor is pretty much a given--it's an excellent Pokemon. Empoleon is a neat option that gives you some extra type coverage.

Honestly, it's very easy to build a good steel team. Steel is one of the best typings in the game along with dragon and water.

Ok i will be using:
Forretress@Focus Sash (Toxic Spikes, Stealth Rock, Explosion, Gyro Ball)
Empoleon@Petaya Berry (Substitute, Surf, Ice Beam, Agility)
Skarmory@Leftovers (Spikes, Whirlwind, Roost, Brave Bird)
Lucario()
Scizor@Life Orb (Bullet Punch, Brick Break, Swords Dance, Roost)
Heatran@Focus Sash(Explosion, Flamethower, Earth Power, HP Ice)

Lead with Forretress, not Empoleon. Empoleon should be saved for late-game sweeping.

Forretress is also better off with Leftovers over a Focus Sash, he's bulky enough that a sash is a waste (most attacks won't OHKO it).

Standard Skarmory is usually Brave Bird/Roost/Whirlwind/Spikes--I think that'd work fine.

Lucario always wants Swords Dance/Extremespeed/Close Combat. For the last move, I'd suggest Ice Punch (since I'd imagine that people are going to use Pokemon like Gliscor and Flygon against you).

Scizor can also run a Swords Dance set or he could Baton Pass, use a Choice Band, etc. There are a lot of options so see what works best for you.

The best Heatran set, by far, is Choice Scarf (although bulky Choice Specs is nice too). I used to run Overheat/Flamethrower/Earth Power/Hidden Power Ice. Hidden Power Grass, Dragon Pulse, Fire Blast, and Explosion are also nice moves.

I myself use a focus sash/band (the full health one), with CC, ES, shadow ball, and dragon pulse/ ice whatever, but I use a mix one. It's good, for getting hit, living, hitting hard, killing, or, if not, ES to finish them.

Pure attack is then same, other then earthquake and an ice move instead.

(Ice punch, or hidden power ice)

I can't say I'm a fan of mixed Lucario--other Pokemon (Tyranitar, Infernape, Salamence, Dragonite, Kingdra, etc.) run those kinds of sets much better IMO.

But hey, whatever works. That's just why I recommended Swords Dance.