That's mathing the wrong Megaman. Zero is how many years ahead of that Megaman? I think that X and Zero were created by Dr. Cain. Weren't they stated to be inferior to the ones created by Dr. Light?
Edit: Wait. I think X was found by Dr. Cain and he created all the other reploids from X's blueprints.
Oh no no no, people here are getting it all wrong.
Zero isn't inferior to X. Zero is stronger than X at the start of the series but they tie a fight in X5. If anything, they are supposed to be equals, although Zero has a higher Maverick Hunter rank.
And X > Megaman. X is Light's newer creation made when he had more experience, knowledge, resources and technology than when he made Megaman. For example Megaman has the Mega Buster mark 5, while X has the Mega Buster mark 17. If they were consoles, Megaman would be Nes and X would be SNES. Zero, who was stronger than X at first, would be definetely stronger than Megaman, especially considering that Bass rivals Megaman, and Wily himself, creator of both Bass and Zero and the one who knows their designs the best, claims that Zero is far stronger than Bass, so: Megaman = Bass < X = Zero (well, roughly).
On a sidenote: X, by default, has an armor that absorbs more than 90% of damage, and when upgraded X's defensive power doubles. Now, Zero would have to have too at least an armor that comes close to that defensive power in order to keep up with him.
That's only because it's the Z-Pipe!!! lol.
Anyway, Sigma's blade looks like Zero's, but that doesn't have to mean they are exactly the same kind of blade (perhaps Sigma's is more of a Beam Rapier with no sharp edges instead of a Beam Saber, that stabs rather than cutting)
Considering that Zero cuts through enemies made of metal on regular basis, some of them much larger than the length of the saber itself, and still keeps the saber as a weapon since X2 while he can rip off metal with his bare hands, you can consider the pipe thing a simple plothole.
Nuh uh Shin, I think Sigma was the first creation by Dr. Cain. Zero was created by Dr. Wily like X was by Dr. Light. That would have to be how Zero carried the Zero virus first.
...MooCow learns.
Concerning the pipe, it doesn't slice through metal by touch. It has to be through Zero's strength, which only means its like a rave version of a regular sword.
Just to clear up some errors:
X was the last creation of Dr. Thomas Light. He is not the original Mega Man, but a completely different robot built by the same creator.
Zero was the last creation of Dr. Albert Wily. Both X and Zero are superior to Mega Man. IIRC, Zero has stated that X is stronger than he, but I'm looking for the exact quote. If I had to put money on it, I'd bet on X. He has been stated to have limitless potential power.
Neither of them were created by Dr. Cain.