I did eventually send them back and get replacements. The new pots have been fine. I still love the set -- it's a great value. It's too bad that their QC isn't more careful. It sounds from this thread that I'm not the only one who's been bitten by bad pans slipping through their testing.
Others on this thread have noted that the way these pans are stamped, there can be failures. I'm sure this is true, but it seems to me like these types of defects could be caught ... you don't see these kinds of complaints online about All Clad or Calphalon Tri-Ply, even though I'm sure they have similar manufacturing constraints. Having shoddy QC, and doing all these free replacements, can't possibly be helping Tramontina keep their costs down.
Griping aside, I still recommend this set to others. You can't beat the value. It's amazing to me that a company that must have very small margins is able to have such good customer service in terms of replacing items that customers aren't happy with.
There is no easily discernable seam in the pot; the dark ring you mention in the picture is a reflection in the curve of the metal (odd that it goes all the way around in the picture). The reason I call it a seam is that it's the only explanation I can think of for why these scorch marks seem to emanate from tiny pockets that run in a ring above the bottom of the pan. Why else would there be these holes opening up in a perfect ring? Maybe there's a reason I haven't thought of ... perhaps the aluminum has burrs or imperfections at these points that make the SS thinner there which causes hot spots.
After reading rave reviews on various cooking sites, and hearing about a thumbs up from Cooks Illustrated, I decided to take the plunge and buy a set of Tramontina TriPly cookware from Walmart.com. (Ended up going for the set because it had multiple items that I wanted to add to or replace from my current collection, including their nice 12qt stockpot.)
After getting the set I was very excited. The build quality wasn't quite at All-Clad levels (a few superficial nicks/scratches), but I wasn't concerned. They were heavy and looked like they'd last a long time.
Needless to say I was shocked when my wife used the 2qt pot to boil some water (pot 2/3 full, medium-high heat), and it ended up with a bunch of odd looking scorch marks emanating from what appeared to be perforations along the inner seam (between the bottom piece of SS and the more highly-polished side piece). The whole point of SS TriPly is that you have a single smooth surface of SS that can be easily cleaned, etc. But these scorch marks show that on a Tramontina, this isn't a single surface, but two surfaces joined by a seam that apparently begins to fail after boiling water a single time.
This is the NFS rated Tramontina TriPly, made in China. (The full TriPly, not the cheaper line with the disk in the bottom.)
Needless to say I'm pretty bummed out. For point of reference, I have a Calphalon TriPly saute pan that has received heavy abuse for 7 years, and always cleans up beautifully with a little barkeepers friend. I've never seen anything remotely like this with the Calphalon. I also did a lot of searches online to see if other people were discussing this, and couldn't find anything, which leaves me confused. How can everyone else have such a great experience with Tramontina when my pot did this on the first time use?
Has anyone seen anything like this before?