After the seemingly impossible task of producing a steel to meet these terrific conditions had been successfully accomplished, the next question which arose was to produce a machine which was sufficiently powerful to stand the work done by the tool, and so fast has been the progress made by the tool steel producer, that many of our modern manufacturing industries of today are constantly having to introduce new and heavier machinery into their various machine shop and tool rooms in order to keep pace with the possibilities of the tool made from the modern High Speed Steel. Now, if we were to run an experiment with a test piece made from High Speed Steel similar to the one which we ran on the simple Carbon Tool Steel, we would find that many of the same phenomena previously noticed would again be recorded. Probably the most important difference would be the fact that instead of having to quench the same in water it would be desirable to use a bath of oil. In fact, water would cause the High Speed Steel to cool off far too quickly so that it would be likely to crack and be rendered useless. A peculiar action of the various elements in High Speed Steel is very likely to materially retard the change of one allotropic form into another. In fact, the change is so slow that after a piece of High Speed Steel has been heated above the critical temperature, it will actually retain its hardened or austenitic condition even if allowed to cool in the air, and it would only be possible to get it back into its softened condition by the lengthy process of annealing. Annealing is the process of undoing exactly what the act of hardening accomplished. Long tubes are filled with the tool steel bars and sealed from the air and then placed into the annealing furnaces, wherein the annealing temperature is maintained for a sufficient number of hours, until the steel has had an opportunity to become thoroughly softened. As before stated “drawing” or “tempering” means the careful re-heating of the steel to 400 degrees Fahr. to 600 degrees Fahr., thus allowing a slight “slipping” of enough of the higher allotropic solution to a lower form, which it is always eager to accomplish at temperatures near the point of recalescence. This, of course, relieves the excess brittleness of the hardened steel. Annealing is the complete release of the higher allotropic form of the solution and the “trapped” carbon which allows of their return to the normal condition of pearlite and alpha iron. Therefore, it is necessary to heat the steel above the point of recalescence and cool more or less slowly. Different speeds of cooling give different grain, size, structure and physical property.