2372 degrees, Yellow white.
2552 degrees, White welding heat.
2732 degrees, Brilliant white.
2912 degrees, Dazzling white, bluish white.
In tempering, I let the oven cool down to the temperature that I need to draw the temper for the job that I
need. I then put the part in the oven, then let it cool down over night.
ANNEALING
In some cases, you may need to anneal the tool to do some machining or changing. The annealing of
steel consists in heating it slightly above the critical temperature range and cooling it slowly in the oven.
The steel is then totally annealed. The steel is held at this temperature usually not less than one hour for
each inch of the thickest section of the part being annealed.
By annealing after machining this will also remove any stress or hard spots caused by machining. The
temperature required for annealing varies for different steels. Low carbon steel may be annealed at
about 1650 degrees F. The temperature should be maintained long enough to heat the entire piece
evenly throughout.
Care should be taken not to heat the steel much above the decalescence or hardening point. When
steel is heated above this temperature, the grain assumes a definite size for that particular temperature,
the coarseness increasing with an increase of temperature.
Moreover, if the steel that has been heated above the critical point is cooled slowly, the coarseness of
the grain corresponds to the coarseness at the maximum temperature. Hence, the grain of annealed
steel is coarser, the higher the temperature to which it is heated above the critical point.