CAUSE ANALYSIS OF ZAM SURFACE BLACK SPOT DEFECT AFTER STAMPING
In response to the phenomenon of black spots on the surface of hot-dip galvanized aluminum magnesium plates of Tangshan Iron and Steel during the stamping process,detection instruments such as optical microscopy(OM),scanning electron microscopy(SEM),and energy dispersive spectroscopy were used to analyze the reasons for the appearance of black spots on the surface after stamping.The results showed that during the stamping process of hot-dip galvanized aluminum magnesium coated steel plates,the coating cracked,and lubricating oil mixed with foreign particles gathered at the wide cracks,resulting in black spot defects.