Study on Phase Structure and 60° V Bending Powder Properties of Galvannealed IF Steel

Based on a continuous hot-dip galvanizing production line of industrial production, the influence of alloying temperature on the phase structure, Fe content and plating resistance to chalking of IF steel galvannealed coating was studied by using scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma spectrometer (ICP) and 60° V bending equipment. The results show that when the alloying temperature ranges from 485 to 545 ℃, with the increase of temperature, the η and ζ phases in the plating disappear in sequence, and the δ and Γ phase contents increases gradually. Moreover, the mass fraction of Fe in the coating increases from 7% to 12%, and the powder width grows from 2.45 mm to 4.23 mm. When the alloying temperature is in the range of 515 ℃ to 530 ℃, the coating phase structure is mainly δ phase, Fe content in the coating is about 10%, and the powder width is less than 4 mm. The coating has an excellent comprehensive performance. The results reveal that the plating resistance to chalking of the galvannealed coating of IF steel strips can be achieved by controlling the alloying temperature, which provids technical support for mass production.