There are some characters that seem like perfect foils for one another in ways that at first appear straight forward, but grow more complex the more you dig deeper. Magneto is strangely bound to heroes with metal-based abilities, with characters like Wolverine and Colossus finding themselves facing off against the "Master of Magnet" quite frequently.
Iron Man, however, rarely seems to cross paths with Magneto. Not to say he never has, but it's a match-up that rarely occurs, which is ironic since even their names link them together. So, with little to go on in the source material, let's breakdown which of the two would win in a fight. Would Magneto hold Iron Man down for the count, or would Tony Stark scrap Magneto?
Magneto's Powers Aren't a Huge Factor
Of every Marvel superhero, Iron Man might be the absolute worst villain to pair up against Magneto. At least, it seems that way at first glance. After all, Magneto is the master of magnetism, able to control metal with his mutant abilities. Iron Man is a character who is completely dependent on his technology, crafted from his metal-based tech. In theory, Magneto could just clench his fist and implode the suit through Tony's ribs. He can detonate the Arc Reactor right in his chest, burning a hole through him. Or, at the very least, just deactivate the armor.
However, when the two faced off in Avengers vs. X-Men, Iron Man found a solution to this key problem: create a suit comprised of carbon nanotubes. Iron Man has developed multiple suits perfectly suited for perfect situations, such as the Hulkbuster suit that is designed to counter the Hulk's strength and the Thorbuster armor that can take down Asgardians. Tony Stark took into account every major power that will be thrown against him. By comparison, preparing for a fight with an Earth-bound mutant isn't too much of a stretch. His anti-Magneto suit is designed to counter Magneto's abilities so that the villain can't just end the fight in a few seconds.
When concluding who will win, it's vital to remember that Magneto is one of the most powerful mutants around, but Iron Man plans ahead of every major fight. He's arrogant, but not stupid.
What Are Iron Man and Magneto's Power Sets?
Without Magneto's obvious advantage, we move onto the next level: the two dealing damage to one another. Magneto can throw anything that has metal around at Iron Man, from buildings to satellites. On top of that, Magneto's magnetic shields can repulse just about every major weapon Stark has on him. The repulsor beams would be as effective against Magneto's defenses as Cyclops's optic beams: not effective.
However, Tony Stark is also incredibly powerful. Due to his resources, he's able to access high-leveled weapons throughout the solar system. He's a hero who fights threats like Thanos, all using whatever tech he can scrap together. But, then again, as all his weaponry is electrically powered, all it would take for Magneto to short out Tony's suits is one well-aimed EMP.
But all of this ignores a key factor: Magneto's strength comes mostly from his mutant abilities. In a real fist-to-fist battle, Magneto's essentially a physically fit person. He's not able to trade blows as Iron Man can. Magneto is best from a distance, even if that distance is the other side of the planet.
Did Iron Man and X-Men Fight in Avengers vs. X-Men?
As mentioned before, Magneto and Iron Man faced off during Avengers vs. X-Men. Specifically, the two fought in AvX: Vs. #1. The fight starts after Magneto realizes he can't just compress Tony's suit, with the villain dropping a building on him. The early fight especially consists of Magneto underestimating Stark, trying to end it fast, but Tony keeps getting up.
So Tony unleashes a set of probes that nullify Magneto's magnetic abilities, restraining his strength while bombarding him with repulsor blasts. This puts Magneto immediately on the defensive, with him using all his focus to put shields up. All the while, Stark is accessing his system of satellites to bombard Magneto with electrical energy.
Magneto responds by dismantling the various satellites, cutting off Stark's extra weapons and, effectively, breaking through the magnetic nullifying tech. But this is where Magneto makes his huge mistake: he lets Stark get within punching distance. The fistfight lasts for half a page before Magneto goes down. Even with Magneto assembling armor from Stark's various satellites, he's put down by a few punches. However, Magneto was at a disadvantage because Iron Man's punches contained the concentrated force of Stark's entire weapon's system. These are blows that could have taken down Thanos.
Did Tony Stark and Magento Fight in Iron Man: Armored Adventures?
The two also fought in the animated series Iron Man: Armored Adventures. This fight is a lot more simple than the AvX fight, with Magneto pressing down against Iron Man using the maximum power of his magnetic power. However, Stark finds a very simple solution to this: he generates weaves that counter Magneto's magnetic abilities. This keeps Magneto from tossing Iron Man around like a rag doll. But even after doing that, Magneto still beats Tony twice in the episode. Tony needs War Machine and Jean Grey (under the alias "Annie Claremont") to stop Magneto. Ultimately, in both fights, Magneto overwhelmed Stark very, very quickly, just by throwing things at him or finding ways to interfere with his armor's functionality with his powers.
Iron Man: Armored Adventures features toned-down versions of both heroes. The AvX versions, on the other hand, feature both at their peak potential, and, even then, every attack Tony sends to Magneto gets dismantled and broken down. It's only because Stark got up close to Magneto and unleashed all his power into a few punches that Iron Man managed to win. If Stark isn't totally prepared to take down Magneto, the villain will win easily.