Do all carbon steel pans warp?

If you have, indeed, not used overly high heat then your burners might be too small for the particular pan, and the heat is concentrating in the center. This is an especial problem with electric burners, but it can happen with gas, too.

 

I haven't tried any carbon steel, I guess I could help you. /img/vbsmilies/smilies//smile.gif

 

Most people who cool a hot pan in the sink run cold water in it. The cold water will warp the pan and the only way possible for the hot part to warp is to pull the middle up. Did you cool these off in the sink ? If you did not, then the gauge steel that the manufacturer started with was to thin and ... Cast iron pans will not do this.

 

Hard to say why it happened.  But, they're easy enough to flatten. 

First, remind yourself that you are smarter than a pan.  Especially one from France.

Then, cut yourself a piece of 2x4 about 1/2" shorter than diameter of the pan's bottom, i.e., just short enough to fit flat in the pan if the bottom weren't warped.  

Heat the pan.

Set the pan on a flat piece of concrete (a thick steel plate would be better, but how many people have those sitting around?).

Put the 2-by in the pan and start whacking the heck out of it with a hammer.  Turn the board so every part of the pan gets flattened, but concentrate in the center. 

Let the pan cool, reheat and repeat.

If the crown is on the bottom, you have to find something big enough to support the pan's rim, but which allows the handle to extend beyond the surface -- so the pan sits flat; and of course, you'll want a 2-by a few inches longer than the pan is wide. 

If you're very thorough, you'll flatten both sides each time you flatten. I don't.  But you could.

Pans which have warped are more prone to warp again.  But if you're easily amused like me you can play this game for a long time.  I've got a Calphalon skillet that's been flattened at least once a year for at least twenty years.  Can't kill it.

BDL

 

My small modification to the flattening process - steel Matfer 12" skillet, approx 3mm thick:

I prepare the thick wooden block from pine (spruce - any soft wook) to fit in the skillet and the skillet - upside down- is sitting on the block, handle protruding away (on stairs or on very heavy workbench.)
I prepare also hardwod straight square block and 2kg (5pound) hammer.
I preheat the pan on largest burner on medium flame (5 min), than put the stove on high preheat also rim of the skillet as much as I can. I move the skillet over the flame to preheat evenly, but as hot as possible. Burner above 4kW is appreciated.

While the skillet is very hot, I place it upside-down on the soft-wood and hit the skillet through hardwood block (endgrain) in way described above - rotating the hardwood block, flattening the whole bottom. It must be done quickly, or reheat again. The wood should smoke lightly.
After straightening, I let it cool down slowly.
Next step - i fill the skillet full with normal salt, and heat it on the largest burner on high power for minimum 45 min and than let it cool down (sort of annealing whole pan and removing some stresses).
Be carefull with the salt - it is white and seems to be cool (not emiting the heat), but it is very hot in the process.

All the best.
L.

 

Wow, on high for 45min. I'd be afraid of taking a burner out doing that.

I'm more heavy handed in this process. Without heating I just support the pan on the side necessary and use an old crocket club as the wood, right in the center, and take some progressively harder wacks with the 5-pounder. Then pound the bottom with the hammer to remove ripples that may form there. Wear ear plugs, and maybe don't do things this way with more expensive pans.