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Aiming at the streak defects on the surface of high-quality automobile steel SP121 after stamping, the surface profile of the streak defects was analyzed by a confocal laser scanning microscope (CLSM). The micro-morphology and element content of the streak defects area were analyzed by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results show that compared with the normal area of the strip steel surface, the surface roughness features of the streak defects area of SP121 after stamping are not apparent. There are many linear defects and dot defects perpendicular to the streak defects. The energy spectrum detection shows no element abnormality in the streak defects area. The surface streak defects of SP121 after stamping are caused by the poor contact between the strip steel and the stamping die, which leads to the poor fluidity of the materials during stamping, and finally, the streak defects are formed.

In view of the chromatic aberration defects on the surface of hot-rolled strip A510L after pickling, the microscopic morphology features of different positions of the pickled strip surface were compared and analyzed by using laser confocal microscope (CLSM), and the generation mechanism of chromatic aberration defect was studied by using high-resolution scanning electron microscope and energy dispersive spectrometer (EDS). The results show that the main cause of surface chromatic aberration defects on the surface of pickling plate A510L is closely related to the interface state between hot-rolled raw material substrate and iron oxide scale, and there is an enrichment area of Fe2SiO4/FeO binary eutectic near the hot-rolled raw material substrate and iron oxide scale, and the proportion of Fe2SiO4 is higher as it approaches the strip steel matrix, and Fe2SiO4/FeO has a strong pinning effect, which leads to the adhesion of iron oxide scale. The existence of Fe2SiO4/FeO changes the structure of carbon steel iron oxide scale, which makes the bonding force between iron oxide scale and strip steel matrix increase the difficulty of pickling process, and finally presents the surface chromatic aberration defects after pickling.