Effect of Continuous Annealing Temperature on Microstructure and Properties of Ti-IF Steel under Ultra-fast Cooling Addition
The effect of continuous annealing temperature (750℃,780℃,810℃,840℃ and 870℃) on mechanical properties,microstructure and texture of a Ti interstitial free steel (IF) under ultra-fast cooling rate of 1000℃/s has been studied.The morphology of the tensile fracture surface at different annealing temperature is observed with scanning electron microscope.At the same time,combined with transmission electron microscope and X-ray diffraction,the precipitation behavior and texture are analyzed.The results show that under the cooling rate of 1000℃/s,the r value of steel annealed at 810℃ (3.03) increases a lot compared with that of common cooling rate annealed steel (2.6).With the increasing of annealing temperature,the yield strength increases between 750℃ and 840℃ and reaches its highest point (130 MPa) at 840℃.Then the yield strength decreases to 124 MPa at 870℃.The ultimate tensile strength reaches its maximum (286MPa) at 780℃ and decreases to 275MPa at 810℃.The elongation,which remains above 50 %,decreases before 810℃ and increases to 53 % at 870℃.The r value increases between 750℃ to 810℃ and reaches 3.03 at 810℃.The minimum r value is 2.2 at 750℃.The microstructure is mainly of equiaxed ferrite and the average grain size is 26 μm when the annealing temperature is 810℃.The equiaxed dimples can be found when the annealing temperature is 810℃.This is consistent with excellent plasticity of the steel.TiN precipitates can be found in all steel.When the annealing temperature is 810℃,ellipsoidal TiN,with the average size of 10 to 30 nm,is observed and the annealed texture is mainly composed of 111 texture.
IF steel precipitation texture annealing temperature continuous annealing
ZHENG Ruwen SONG Renbo CAI Hengjun
School of Materials Science and Engineering, University of Science and Technology Beijing,Beijing 10 School of Materials Science and Engineering, University of Science and Technology Beijing,Beijing 10
国际会议
成都
英文
595-598
2016-11-16（万方平台首次上网日期，不代表论文的发表时间）