Abstract:By the observation of microstructures and the analysis of SEM(scanning electron microscope) and EDS(energy dispersive x-ray spectrometry), the hot rolled plate peeling defects of pipeline steel are studied. It shows that the surface microcrack is found in continuous casting slab, and the elements of O, Si, Al, Ca, Cu are enriched around the crack. The main reason for hot rolled plate surface peeling is the slsb surface microcrack which is caused by oxide inclusions and copper content overproof. Finally, the influence mechanism of nonmetal oxide and low melting point metal on slab surface microcrack is discussed, and the preventive measures are presented correspondingly.