Effect of gradient temperature rolling process on precipitation behavior in Q690D steel

Abstract

Abstract In this paper, the second phase precipitation model is incorporated into the finite element simulation system of hot rolling process through the secondary development subprogram VUSDFLD of ABAQUS, and the simulation analysis and calculation of nucleation rate, volume fraction and size of precipitates under different temperature fields and strain fields are realized. The size, morphology and distribution of the microalloyed carbonitride precipitates in Q690D steel under gradient temperature rolling (GTR) and uniform temperature rolling (UTR) were studied by laboratory rolling experiments. The results show that the nucleation sites of the microalloyed carbonitride precipitates in the matrix increase under GTR, which is conducive to the nucleation of new precipitates and promotes the re dissolution of large precipitates. Finally, after tempering, the precipitate particles are distributed randomly on the ferrite matrix, and the size is refined by 20 ∼ 35 nm, resulting in obvious precipitation strengthening and microstructure refining effects.