snip
Nope! You don't want any oxygen to get in. The amount of carbon you put
in is much more than needed for both hardening and combining with any
residual oxygen in the pipe. I use a similar method for annealing. Making
small tools from allen wrenches or concrete nails, I put them in the pipe
with 3 to 6 sq. inches of brown paper to get rid of residual oxygen, and
put the pipe in the fire as Bob does. After the pipe gets to temperature,
let the fire die out. When all is cool, nice non-scaled annealed steel.

Bob
*****************
Years ago ('50's) in one of the old Popular Science type mags there was
a 'readers speak'
article where a man made his own threading dies by using a hex nut with bolt
stopped flush with one
face of the nut. He then drilled his three holes, (half in the nut, half in
the bolt) removed the bolt, and now he had a 'soft' die.
He then heated that nut/die cherry red with his o/a torch and sprinkled
powdered sugar on the inside of the red hot bolt.
He said that hardened the threads of the bolt (now a die) sufficiently.