JLA Avengers is the best comic book ever published period.

My dad can beat up your dad.

"As to whether he could penetrate a forcefield generated by the ring while it's being used, that's a different topic. "

No, it isn't. If a ring is powered, it will (at least in modern interpretations) protect itself. If a "laser" (i.e, heatvision) is blasted at it, it will use its power to protect itself, presumably with a forcefield.

If it is not powered, and unless it is made from a metal that is impervious even to the heat of the sun (which is unlikely), Superman's heat vision should be able to completely vaporize it if necessary.

Now, somehow the ring is "programmed", and in order to say that it can still function in melted form, that programming must be completely separate from any physical structure or circuitry within the ring.

The question of whether Superman's heat vision can melt a Green Lantern ring is exactly the same question as whether his heat vision can penetrate a Green Lantern's forcefield.

Unless it becomes the question of what it takes to melt a Green Lantern ring in a fully depowered state. Where the answer might be that a simple blacksmith's forge can do it.

And the question of whether a melted ring can still be used to harness lantern energy, is dependent on how the ring works. If we presume that the metal is just a rare metal capable of storing lantern energy and that its programming exists as pure lantern energy, separate from any physical "computer" technology in the ring, then the metal in any shape would retain that ability. 

Yet there has to be some way that the "programming" controls the ability of the metal to harness and direct lantern energy, or anyone stumbling on a raw piece of the metal would have access to lantern power.

So in some way that would either have to mean that A) the ring can never be fully depowered, as it needs to retain its programming in lantern energy form, as well as its basic self-defense mechanisms,(in which case it could be melted but reshape itself, evade the heat or protect itself with a forcefield) or B) There is actual circuitry in the ring that controls its programming, so that even in a fully depowered, fully drained state it can be recharged and retain all its memory and programming. Meaning that if it is sufficiently melted, it would be useless.

So it's actually pretty involved. But in pragmatic terms I'd say that if the ring was wielded (against its will) by a villain, Superman might melt it or make it so hot the villain takes it off. If it was wielded by a good guy Green Lantern, I'd say not.

Superman gettiing in a fight with a Green Lantern and using his heat vision to melt the ring sounds like a "My favorite superhero is cooler than your favorite superhero" story that should never be told. 

Steve Horn wrote: Those that criticze the JLA/Avengers have never read the JLA/Avengers.  JLA Avengers is the best comic book ever published period.

Since you've called out pretty much anyone who has even an ounce of criticism for the book, care to explain why you think JLA/Avengers is "the best comic book ever published period"?