Abstract
Following the 17th. report (Tetsu to Hagane Vol. 42 (1956), No. 6 p. 37), the rapid softening method by water .and air annealing of high speed steels (SKH 8 & SKH 6) was studied by micrography and hardness test.
The results obtained were summarized as follows:
The hardness of the quenched high speed steel that had been annealed in water or air from 800°C (just below the transformation point) was nearly equal to such hardness at which was possible to be machined, although it was less softened as compared with the hardness obtained by full annealing furnace.
