Unfortunately, uncontrolled heating can do more damage than good. Cherry red is great for decarbonizing, but can change the properties of the pipe material and alter the shape.
The original pipes are not stress relieved after fabrication and welding, so there are residual stresses. Unless you have a way to fixture the pipe in the process, you will have to control the heat at a low temperature. You want to be well below the transformation range, and the critical temp for carbon and low-alloy steels is in the 1335 - 1370 F range.
In fact, at 850 or so, the nickle plating will oxidize and discolor. The heating process will temper the pipe material which acts to increase ductility and toughness, but reduces hardness and strength. The higher the temperature, and the longer the cycle, the lower the hardness and strength. Also, not so good.
If you can heat and cool the pipe uniformly, and control the temperture to about 800 F, you might have a business. Of course, if you could find someone who has a tooling burnout furnace, that'd be easy. If you could convince someone to dirty up their vacuum furnace, you wouldn't have to worry about discoloration. (That's a whole other funny story about why consumers buy "blued" titanium exhaust cannisters, etc.)
Your self-cleaning over gets up to 900 F or more, but mostly, they are not so worried about the same performance issues and material properties as your pipe.
Oh, and the original "hot-tanking" went out here in Calif about 10 years ago.
Anybody got a furnace at work we can all use?
Barry