Effect of Deformation Temperature on Nanoprecipitates and Tensile Behavior of Ti-Nb-Mo-Ce Microalloyed Ferritic Steel

The microstructure, tensile deformation, and texture evolution behaviors of Ti-Nb-Mo-Ce microalloyed high-strength weathering steels were studied under different deformation conditions. The effects of continuous dynamic recrystallization and deformation-induced ferrite transformation (DIFT) on the nanoprecipitation behavior and microstructure were analyzed and compared. The results demonstrated that austenite recrystallization zone rolling and isothermal treatments were combined to obtain the high-strength ferrite weathering steel comprising nanoprecipitates with a yield strength of 635 MPa, a tensile strength of 750 MPa, and a 21.2% elongation. Further, the non-recrystallization rolling in the austenite region benefitted the deformation-induced ferrite transformation, and the texture that was obtained under the DIFT microstructure conditions was mainly (110)[1-10]. Many epsilon-fiber textures, //TD, appeared under the microtensile deformation condition, and the sigma-fiber textures, //ND, were weakened compared with those of the non-tensile deformation microstructure. Although the grains of the ferrite, which were prepared via rolling in the non-recrystallized region of the austenite, followed by the isothermal process, were finer, the size of their nanoprecipitates increased significantly and deteriorated the mechanical properties.