what happens to stainless steel cookware after prolonged heat while empty?

You know, like when we 'burn' water 🙄

We have what is more than 50 year old revere ware sauce pans.
and used only for heating water or cooking something in a liquid.

The smallest saucepans have boiled dry frequently and not been noticed right away so between burnt oatmeal and boiled away water they are looking sad...it's a gas stove if that matters.

Does the stainless change with heat into something I don't want to cook in?
(can I throw give them away?)
We mostly use iron and some nice heavy bottomed stainless that I protect more carefully.

It may warp or even discolour but I doubt it will change chemically -- it's not hot enough for that. Personally I would give it a good scrub with an aggressive scrubby and keep using it.

If you decide to stop using them in the kitchen, there are tons of uses for old stainless steel pots on a homestead.

It’s been (cough) 30 years since my metallurgy classes, but I think they’re still safe.

At high enough temperatures they could warp, or even oxidize, but that’s just rust that can be scraped off.  They might lose their structural integrity, so they could break unexpectedly.

I’d be more worried about starting a fire with whatever was in the pot, or at least setting off your fire alarms.  And you’re probably getting more toxins from the gas stove than you ever could from your pots.

(Edited to add: I love old Revere Ware! At least donate it to charity!)

thank you both!
We have gotten good at cleaning them after these episodes.
They have not warped at all but have a bit of an iridescent look sometimes?

The gas is propane so not as bad as natural gas I hear but believe me I miss the wood stove.

We did get an electric water kettle that shuts itself off so it's down to oatmeal and reheating coffee or tea in these little pans.
I think I've figured out why this happens so often now.
In the past we've either lived in a one room cabin or a house with an open kitchen/ dining room .
Here, the kitchen is separate and walking into the next room becomes an 'out of sight out of mind' thing.

The pans might still be retired to grain scoops or head to the thrift store.

Judith Browning wrote: Here, the kitchen is separate and walking into the next room becomes an 'out of sight out of mind' thing.

Do you carry  your cell-phone? Most of them have some sort of an easy to set timer. Can you leave the phone in the kitchen when not using it, so it's always handy for doing double duty as an alarm?

I totally hear you about the 'out of sight' thing... Alarms have saved me more often than I like to admit... My phone is just one of my options.

Over the years I've killed a couple of stainless steel pans by overheating them, but the point of failure was the heavy bottom part coming partially unstuck from the rest of the pan. This made them pretty useless at conducting heat after that happened.

Judith Browning wrote:They have not warped at all but have a bit of an iridescent look sometimes?

Not having seen them, I'd conjecture that this is just minor surface oxidation, the same sort of thing which a blacksmith or tool maker would watch when "letting the colors run" to temper hardened steel.  It might have a light brown (straw) color, or even a reddish, bluish or purplish cast, depending on how hot it got, and just what was in the pot when it got hot.  Contrary to the name, stainless will oxidize or corrode, but it is much more resistant to this than is common steel, for sure.  As a kid, I had a cute little drop point Gerber lock back pocket knife, with linen Micarta handle slabs, which eventually got a small spot of light surface rust on the blade from being in my sweaty kid pocket (perhaps that's TMI, but there it is).  To prevent oxidizing under more benign or pedestrian conditions (i.e. not overheated on your stove top), stainless is often "passivated" with citric acid or some other such treatment.  But, get it hot enough, and stainless will show "color".

In my checkered past, I worked for a commercial glazing company (not once, but twice).  I remember my boss deliberately oxidizing stainless flathead screws to a dark brown color to try to match the "bronze" color of aluminum Kawneer brand door frames.  He was able to get a pretty good match, though I forget the details of time and temperature required.  Whether mixing stainless fasteners with aluminum door frames was a good idea, especially in a place where everything is salted heavily all winter long, I'll leave to the corrosion engineers.  Generally, in my experience, the aluminum suffers over the long term.

Maybe I'm a Pollyanna, but if it's just oxidation, I wouldn't worry about it.  If it really bothers you, it should come right off with some fine aluminum oxide buffing compound (the stuff for polishing aluminum car wheels and so forth) and a bit of elbow grease.  If it's just surface corrosion, that is.  I have some "Mothers" brand "Mag and Aluminum Polish (Perfect for All Metals - Shines & Protects)" I'd be happy to let you try, if you were just next door.  It also works tolerably well to polish up frosted plastic headlight covers, though probably not as well as the fancy "ceramic" multistage headlight polishing kits.  I think mine came from Walmart, or maybe Auto Zone.