On the Ar1 Transformation (2nd Report)

The mechanisms of austempering of steel were discussed and the structures of austempered steels were explained as follows: (1) Pearlite is a decomposition product of γm in the temperature range, in which the growing Velocity of Fe3C is faster than that of αm (2) Bainite is a decomposition product of γm in the temperature range, in which the growing velocity of αm is faster than that of Fe3C. (3) Upper bainite is the bainite in which the Fe3C separated out primary γm and lower bainite is the bainite in which the Fe3G separated out secondary from αm.