Study On Microstructure And Properties Of High Ti Microalloy Hot Rolled High Strength Steel

Taking the development of low-cost and high-performance microalloyed highstrength steel as the research background,according to the performance requirements of the third generation of advanced high-strength steels,the Gleeble-3500 thermal simulation tester and universal tensile tester were used for testing.Through SEM,TEM,EDS and other analysis,the precipitate composition of the high Ti microalloyed steel was studied.The main conclusions are as follows:1)The the static CCT curve of the experimental steel is drawn.It is found that the products of the undeformed austenite at different cooling rates are bainite.In addition,it is determined that the experimental steel can obtain a more ideal room temperature structure when the final rolling temperature is 860 °C and the final rolling reduction is 20%.2)The stress relaxation method is used to study the austenite recrystallization law.The deformation temperature has the greatest influence on recrystallization.The recrystallization process is the fastest under high temperature and high deformation.In addition,the static recrystallization activation energy Q=276.45KJ?mol-1.A static recrystallization Avarami equation is established,and n=1.144,A=1.68×10-14,p=-1.2,q=-0.443)The SEM,EDS and physical and chemical phase analysis are used to analyze the precipitates of the high Ti microalloy slab,and the microstructure characterization and mechanical property analysis of the hot rolled sheet were performed.The results show that the tensile yield strength and uniform elongation at 1/4 of the transverse direction are higher than those at the edges and the center.The elongation at break in all parts exceeds 20%.The strong plasticity matches well,which is consistent with the results obtained from the analysis of the microstructure.Figure 43,Table 8,Reference 53...