Study on Microstructures and Properties of Ultra Low-carbon Nb+Ti-IF Steel

Under the laboratory conditions,the crystallizing regulation and the effect of annealing process on the properties and structure of Nb+Ti-IF steel were studied,the experiment showed that:the starting crystallization temperature of IF steel is 680℃, under 800℃ constant temperature conditions,the time of finished crystallization is 60 seconds.Taken together,when the annealing temperature is 870℃,we get the excellent properties:tensile strength is 313 MPa,yield strength is 156 MPa,elongation is 50.8%,n-value is 0.281, r-value is 2.07. The annealing texture is made of strong γ fiber and weak a fiber texture,γ-fiber texture is mostly composed of {111}〈110〉texture and {111}〈112〉texture, {111}〈112〉texture is dominant.