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BELL SYSTEM TECHNICAL JOURNAL 



Fig. 8 — Mag. 3500X. Fig. 8 shows a troostitic development which had formed 

 along an old austenitic grain boundary. The excess constituent is starting to clear 

 at the grain boundary. Well developed pearlite is revealed. The large light- 

 colored grain covering the center of the field is just starting to break up into two con- 

 stituents. Formerly grains of this kind, becauseof lack of resolution, were thought to 

 be in all probability solid solution grains. These grains must represent a state very 

 nearly that of freshly formed troostite. 



