Strengthening mechanisms of Ti and Nb bearing steel plates produced by thermomechanical control process have been investigated. The strengthening of Ti bearing steel plate is induced by precipitation of Ti carbide, ferrite grain refining, and increase in bainite volume fraction. The strengthening of Nb bearing steel plate owes to precipitation of Nb carbonitride, ferrite grain refining, and increase in bainite volume fraction. The major factor of strengthening of Ti and Nb bearing accelerated cooled steel plate is the increase in bainite volume fraction.
