(1. Materials Science and Engineering, Chongqing University, Chongqing 400030, China 2. Nanjing Iron and Steel Co., Nanjing 210035, Jiangsu, China 3. Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials, Chongqing University, Chongqing 400044, China)
Abstract:The precipitation of inclusions in continuous casting process has an important effect on the microstructure and properties of billets. In order to study the Precipitation Law of TiN and TiC inclusions in Ti microalloyed Q345 steel, the thermodynamics of TiN and TiC formation was calculated. The solid/liquid temperature, the precipitation temperature of carbonitride, the equilibrium/actual solubility product of TiN and TiC at different temperatures and the initial concentration of Ti and N required for precipitation were calculated. Precipitation of TiN and TiC during the solidification process of high titanium steel. The results show that TiN and TiC can not precipitate above the liquidus temperature, TiN and C begin to precipitate when fs>0.56 in the two-phase region and TiC begin to precipitate when fs>0.92 in the two-phase region because of the enrichment of Ti, N and C at the solidification front, and TiN particles precipitate in the solid austenite, while TiC precipitates at a lower temperature than TiN in the ferrite.