Acicular Ferrite Nucleation Behavior from B1-Structure Compounds in Steels

摘要

Intragranular ferrite (IGF) has been considered as a key concept to improve properties of steel weldmetals and heat affected zone (HAZ). Especially acicular ferrite nucleated from mineral inclusions is expected tocontribute to the improvement of steel toughness, owing to randomness of ferrite orientation. Although somepossibilities have been suggested, the exact mechanism of intragranular ferrite nucleation has not beenclarified yet1). In this study, we focus on the crystal orientation relationship between B1-structure inclusionsand ferrite nucleated from them. To clarify the effect of orientation relationship on acicular ferrite nucleation,steel specimens containing B1-structure compounds were examined. Especially, the orientation relationshipbetween austenite/ferrite (Kurdjumov-Sach relationship) and B1-structure compounds/ferrite (Baker-Nuttingrelationship) was evaluated.