Abstract：The strip defects on the inner wall of parts were observed when the 35 round steel produced by a factory was processed into parts by one customer. In order to analyze the formation causes of defects, the chemical composition, metallography, defect composition and other physical and chemical properties of the defective samples were tested and analyzed by direct reading spectrometer, digital microscope and scanning electron microscope. The analysis results showed that the defects on the inner wall of parts were caused by the slag curling in the mold during steel continuous casting. The protective slag drawn into the steel was peeled off and exposed on the surface in the subsequent processing of parts, forming the defects of strip pits on the inner wall of parts. By investigating the production process of the original heat of defective parts, the causes of slag entrapment in the mold were determined, and corresponding measures were taken to prevent similar defects from happening again.
2023, Vol. 41 
