Cause analysis and improvement measures of scaly defects on inner surface of 37Mn5 steel pipe

In the production process of 37Mn5 steel pipe, a large number of scaly defects were found on the inner surface of the pipe after the hollow bloom was pierced. The causes of scaly defects were studied by means of macroscopic observation, chemical composition analysis and microscopic analysis. The results showed that a variety of large inclusions in the inner wall of 37Mn5 steel pipe would cause scaly defects as the thickness of the pipe wall decreased when the hollow bloom was pierced. The scaly defects on the inner surface of the pipe were significantly reduced after taking improvement measures such as reducing the content of large inclusions in steel.