Corrosion Resistance of Zn-Al-Mg Coated Steel Sheet Cut-Edge

The Zn-Al-Mg coated steel plates with different thicknesses were processed into circular samples with different inner and outer diameters by laser cutting to obtain different ratios of cut-edge area to coating area. The corrosion resistance and corrosion products were observed and analyzed by neutral salt spray test, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The microstructure characteristics, phase composition and corrosion resistance of the Zn-Al-Mg coating notch were determined. The results showed that the corrosion products of the steel plate were mainly basic zinc carbonate Zn₄CO₃(OH)₆·H₂O in neutral salt spray environment. With the increase of the ratio of cut-edge area to coating area, the red rust area of the sample cut-edge increased gradually, and when the ratio of cut-edge area to coating area was less than 0.5, the red rust resistance of the cut-edge was better.