Preventing Abnormal Grain Growth of Austenite in Low Alloy Steels

Abstract

Abnormal grain growth (AGG) in austenitic state is studied in low alloy steel in relation with precipitation state. It is observed that initial austenite grain size and precipitation state plays more important role in defining the normal or abnormal grain growth condition than the final one obtained after a heat treatment. Precipitate volume fraction evolution with time-temperature having similar quantity at the end but different initial grain sizes, showed different grain growth phenomenon. Arguments are presented to rationalize the presented experience. A simplified AGG model is applied to understand the effects of initial mean austenite grain size and precipitate size distribution on the subsequent AGG occurrence.