Abstract:
According to the characteristics of a Continuous-annealing/Hot-dip Galvanizing Dual Purpose Line,a series of Ti-IF steels with different carbon content were used to investigate the effect of continuous annealing temperature and annealing time,cold-rolling reduction and prestretching deformation on the microstructure and properties.The results showed that ferrite grain size of the experimental steels almost remained unchanged when annealing temperature increased from 780℃ to 880℃,and the steel with higher carbon produced finer ferrite grains.As annealing temperature increased,yield strength and tensile strength increased,but ultimate elongation and n90 value decreased,however,r90 value remained almost unchanged.As the annealing time increased from 30 s to 45 s,yield strength and tensile strength change little,the ultimate elongation,the n90 value and the r90 value increase.As the annealing time further increased up to 60 s,mechanical properties are independent of annealing time.As the cold-rolling reduction increases,the yield strength,the tensile strength,the ultimate elongation and the r90 value tend to increase,but the n90 value tends to decrease.The r90 value reaches peak value when the cold-rolling reduction is 80%.As the prestretching deformation increases,the yield strength increases obviously,the n90 value and the ultimate elongation decrease markedly,the tensile strength remains almost unchanged,and the r90 value tends to decrease.The continuous annealing Process of Ti-IF steel on a Continuous-annealing/Hot-dip Galvanizing Dual Purpose Line was analyzed.
