This wouldn't be an easy fight. Colossus is made of metal but the Hulk smashes through steel like tin foil. Don't worry about that Hulk movie because he's way more lethal than that in the comics.
Blow for blow, i'd have to give it to the Hulk because I think Colossus has power limitations compared to the Hulk. Hulk's power/strength can't even be measured because he gains more power/strength from his rage.
hulk wins
hulk could win, hulk could punch thought his metal like taking candy from a baby plus the hulk can lift 100 tons and colusso can only lift 70 tons. the hulk as
Resistance to Mind Control
Unusual Mental Abilities
Accelerated Healing
Leaping/Jumping Ability
Unlimited Strength
High Resistance/High Durability
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Colossus would take charge to start with coz his strength level is 100 tonnes not 70(read x-men encyclopedia) and Hulks starting strength is 70 tonnes. Although Colossus is only steel its 'organic steel' and seems to be harder than normal steel. Colossus has been described as nigh-invulnerable so his resistance is prob on a par with the Hulk's.He can also take higher temperatures than the Hulk(Colossus 5000, Hulk 3000 F) so that tells you how resistant to injury/pain he is. Once Hulk gets angry enough, he'll be way too strong for Colossus though.
I always loved Colossus. He is very much underestimated, maybe because he doesn't show off.
In a fight hower, his steel-like skin and his intelligence won't help him much when fighting the Hulk. The Hulk has beaten stronger and smarter guys than Colossus. Lots of time ! I mean, sometimes it's all he does, beating up really strong guys, one after another.
Colossus doesn't fight as many extremely super-powered heroes/villains like the Hulk does. And remember the Hulk has more experience, is certainly stronger when he gets angry and is at least as tough. Probably tougher.
So the winner is... The Hulk (I would like to see the battle though, it would be very interesting).
It would be a good fight for the first 5 minutes, maybe.
Marvel Directory states (now whether this is true or not) that Colossus can lift at least 70 tons, so the upper limit to his strength may not have been gauged. Hulk starts in the 70 ton range, and when enraged surpasses the 100 ton range. C'mon, "Hulk is strongest one there is!" He eats nails and sh!ts barbed-wire. You just don't mess with him.
It would be cool to get Colossus and The Thing to tag team on the Hulk though....