Abstract：The extrusion cylinder assembly consists of two parts, including the shell and the inner lining. An extrusion cylinder assembly was in service for about 11 months. The problem of serious aluminizing was observed in the extrusion process. The inspection showed that there was a crack with length of 1 000 mm in the inner lining. In order to determine the property and reason of cracking on extrusion cylinder lining, the macroscopic analysis, chemical composition detection, electron microscope fracture analysis and metallographic examination with high and low magnification were performed to analyze the causes. The results showed that the main causes of the longitudinal cracking on the inner lining was the nonuniform distribution of material composition, serious segregation, insufficient strength, low ductility and high friability. The continuity of base material was destroyed by the cracks on inner surface during quenching. The material could no longer meet the use requirement and cracking due to fragility occurred.
2023, Vol. 41 
