4. Defectology

Today, internal defects are limited to a few rare blowholes and aluminate inclusions; surface defects are related to rolling conditions.

The internal fatigue faults created by poorly settled aluminate inclusions (as in the period of aluminum quenching already mentioned, figure 15 ), known as "oval spots" and often accompanied by defibration of the rolling fillet in curves, due to aluminate strings, have now completely disappeared.

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