Effect of Nb on the transformation behavior of Nb-Ti microalloyed steels

In the thermo-mechanical processing of niobium microalloyed steels, the strain induced precipitation of Nb(C,N) in austenite impedes the mobility of austenite grain boundaries during recrystallization, leading to the well-known pancaked austenite structure, which is critical to the achievement of the fine ferrite grain size. However, retention of some Nb in solid solution in austenite upon completion rolling in desirable. Solute niobium …