Discussion on the crusting causes of pipeline steel

By the observation and analysis of microstructures, 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 microcrack is found on the surface of continuous casting slab, and the elements of O, Si, Al, Ca and Cu are enriched around the crack. The main reason for hot rolled plate surface peeling is the slab surface microcrack which is caused by oxide inclusions and copper content overproof. The steel cleanliness and continuous casting process can also be considered as important reasons. Finally, the influence mechanism of nonmetal oxide, the low melting point metal such as Cu and continuous casting process on the slab surface microcrack is discussed, and the preventive measures are presented correspondingly.