摘要
Based upon the composition of C-Si-Mn,four types of transformation induced plasticity（ TRIP） steels with different contents of Si and M n were designed,which are subjected to quenching and partitioning（ Q＆P）processes with variable austenitizing temperatures. The as-treated steels exhibits good combination of high strength and substantial elongation. In particular,with austenitizing at 820 ℃,0. 18C-1. 8Si-2. 2M n（ %） steel and0. 18C-1. 8Si-2. 5M n（ %） steel possessed high elongation（ more than 20%） with the tensile strength over 1000 M Pa. The microstructures of the as-treated steels were obtained by scanning electron microscope,the volume fraction and carbon content of retained austenite has been quantified by X-ray diffraction. The designed Q＆P processed steels contained a multiphase microstructure including ferrite,lath martensite,and retained austenite. The volume fraction and carbon content of those steels were higher,which was treated by Q＆P processes with austenitizing at 820 ℃. Due to the TRIP effect during the deformation process,retained austenite gives better stability as well as effectively improves the formability of steels with slightly decreasing the strength,contributing to overall better performance.
Based upon the composition of C-Si-Mn,four types of transformation induced plasticity（ TRIP） steels with different contents of Si and M n were designed,which are subjected to quenching and partitioning（ Q＆P）processes with variable austenitizing temperatures. The as-treated steels exhibits good combination of high strength and substantial elongation. In particular,with austenitizing at 820 ℃,0. 18C-1. 8Si-2. 2M n（ %） steel and0. 18C-1. 8Si-2. 5M n（ %） steel possessed high elongation（ more than 20%） with the tensile strength over 1000 M Pa. The microstructures of the as-treated steels were obtained by scanning electron microscope,the volume fraction and carbon content of retained austenite has been quantified by X-ray diffraction. The designed Q＆P processed steels contained a multiphase microstructure including ferrite,lath martensite,and retained austenite. The volume fraction and carbon content of those steels were higher,which was treated by Q＆P processes with austenitizing at 820 ℃. Due to the TRIP effect during the deformation process,retained austenite gives better stability as well as effectively improves the formability of steels with slightly decreasing the strength,contributing to overall better performance.
