Investigating the Role of TiC Precipitation in Dynamic Recrystallization Behavior of a Novel Ship Steel

Abstract

This study examines the single-pass thermal compression behavior of Ti-bearing ship plate steel across a temperature range of 850–1150 °C and strain rates from 0.01 to 7 s⁻¹, employing the Gleeble-2000D thermomechanical simulator. It delves into the evolution of TiC precipitation and dynamic recrystallization (DRX), along with the austenite decomposition transformation during hot compression and subsequent cooling. Active dynamic recrystallization commences at deformation temperatures above 1050 °C, facilitated by the diminished pinning pressure of TiC carbides. This leads to the development of fine DRX austenite grains, influenced by an increase in strain rates and a decrease in temperature. Simultaneously, the fraction of TiC dispersions decreases as the deformation temperature increases, yet they maintain a consistent size of 5–10 nm. The refined particle size is attributed to their low interfacial energy with the austenite matrix, determined by the first principle to be 0.21 J m⁻². Due to the severe deformation and numerous dispersions, specimens subjected to a thermal deformation regime at 850 °C and a strain rate of 7 s⁻¹ present a peak in hardness, reaching a maximum of 324 HV. The Ti microalloying approach offers pivotal insights into improving the rollability and mechanical characteristics of ship plate steel.