Originally Posted by StuartD

Hulk's always been in and out of trouble due to losing control. That's how his power grows, his anger/rage. The worse it is, the stronger and more out of control he gets.
So Iron Man, fearing that one day he'll go beyond what anyone's seen so far, built a "Hulk Buster" suit designed specifically to fight the hulk.
Even has jet engines on the arms to forcefully push his punches that much harder.

Anyway, that suit of armor was put to use several times but most recently Iron Man, Dr Strange, Reed Richards and and The Black Bolt sent him into space as he was completely out of control. Well, he survived and returned... even madder than before.

He took apart Iron Man's suit pretty easily, as well as every other hero they could throw at him.

http://en.wikipedia.org/wiki/World_War_Hulk