alpha yields gamma TRANSFORMATION BEHAVIOR DURING HEATING FROM ( alpha plus gamma ) REGION IN 0. 18% CARBON STEEL.

The transformation was delayed with increasing an initial amount of proeutectoid alpha before heating. When the amount of proeutectoid alpha before heating was the same, the transformation kinetics was delayed with increases in initial gamma grain size and the gamma yields alpha transformation temperature in the alpha plus gamma region. Microscopic observation showed that transformation proceeded only by the growth of pre-existing gamma , namely, the dissolution of proeutectoid alpha without nucleation of new gamma grains in the proeutectoid alpha particles before heating, the experimental data lay on a straight line and T//0//. //9 increased with increasing particle size.