Boy, this team needs a lot of improvement. Lets start with Bisharp. Bisharp is pretty good, but why Metal Coat?Also, Throat Chop is outclassed by Knock Off. Here is my set for Bisharp:
Bisharp @ Life Orb
Ability: Defiant
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Swords Dance
- Sucker Punch
- Iron Head
- Knock Off
Almost the same, but Knock Off and Life Orb instead.
Heatran is not good. Why charcoal? Heatran almost always runs defensive sets, and for offensive sets, not Charcoal. I would use defensive Heatran. Here is my set for Heatran.
Heatran @ Leftovers
Ability: Flash Fire
EVs: 252 HP/216 SpD /40 Spe
Calm Nature
IVs: 0 Atk
- Stealth Rock
- Taunt
- Magma Storm
- Earth Power
Leftovers is recovery, sr+taunt are support, the rest is STAB and coverage respectively.
Melmetal needs some improvement. Why Iron Head and Double Iron Bash? Why Protect? Protect has no use, except for scouting opponents. Most monotype Melmetal run Choice Band sets. Here is my set for Melmetal.
Melmetal @ Choice Band
Ability: Iron Fist
EVs: 244 HP / 252 Atk / 12 Spe
Adamant Nature
- Double Iron Bash
- Ice Punch
- Earthquake
- Superpower
I used Choice Band, and changed the EVs a bit. I also added more coverage. The speed EVs help outspeed Toxapex.
Excadrill is good, but since it is the only pokemon that benefits from Sandstorm, I recommend you replace it with Rapid Spin, to remove hazards. Also, Leftovers could be replaced by Life Orb to boost damage. Here is my set for Excadrill.
Excadrill @ Life Orb
Ability:Mold Breaker
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Swords Dance
- Earthquake
- Iron Head
- Rapid Spin
I replaced sand force with mold breaker, because if you don't run sand than mold breaker is the best. I replaced Sandstorm with Rapid Spin too. The EVs stay the same.
Corviknight usually runs Bulk Up sets for steel monotype. Also, without attack boosts, your attacking moves don't do a lot of damage.I'm gonna use a different set though.
Corviknight @ Leftovers
Ability: Pressure
EVs: 252 HP / 216 Def/ 40 SpD
Relaxed Nature
- Defog
- Body Press
- U-turn
- Roost
Since you don't have a pivot,I decided to use a pivot corviknight. It can remove hazards, do quite a bit with body press,and heal itself. The EV spread is more defensive.
Also you don't have a Stealth Rock/Spikes user, so Ferrothorn could replace Magnezone. Here is a set.
Ferrothorn @ Leftovers
Ability: Iron Barbs
EVs: 252 HP / 216 SpD / 40 Def
Impish Nature
- Power Whip
- Leech Seed
- Knock Off
- Spikes
Leech Seed is recovery outside of Leftovers. Power Whip is STAB. Knock Off is support. Spikes are hazards.This is the whole upgraded team!
Ferrothorn @ Leftovers
Ability: Iron Barbs
EVs: 252 HP / 216 SpD / 40 Def
Impish Nature
- Power Whip
- Leech Seed
- Gyro Ball
- Stealth Rock/Spikes
Corviknight @ Leftovers
Ability: Pressure
EVs: 252 HP / 216 Def / 40 SpD
Relaxed Nature
- Defog
- Body Press
- U-turn
- Roost
Excadrill @ Life Orb
Ability:Mold Breaker
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Swords Dance
- Earthquake
- Iron Head
- Rapid Spin
Melmetal @ Choice Band
Ability: Iron Fist
EVs: 244 HP / 252 Atk / 12 Spe
Adamant Nature
- Double Iron Bash
- Ice Punch
- Earthquake
- Superpower
Bisharp @ Life Orb
Ability: Defiant
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Swords Dance
- Sucker Punch
- Iron Head
- Knock Off
Heatran @ Leftovers
Calm Nature
EVs:252 HP/216 SpD/40 Spe
IVs:0 Atk
Magma Storm
Earth Power
Stealth Rock
Taunt
I hope I've helped!