Formation Mechanism and Prevention Measures of Chunk Graphite in Heat-resistant Nodular Iron
Author of the article:QIAN Kuncai;ZHU Guihua
Author's Workplace：CRRC Qishuyan Institute Co.,Ltd.,Changzhou 213000,China
Key Words：heat-resistant ductile iron chunk graphite supercooling degree inoculation
Abstract：Based on the effect of the degree of hot metal supercooling on the graphite nucleation in production practice,the mechanism of the formation of chunk graphite in heat-resistant nodular iron was studied.The results show that the thermal centers of heat-resistant ductile iron are prone to the occurrence of chunk graphite,and the main reason for the occurrence of such chunk graphite is that the molten iron has high local component undercooling during the solidification process.Improving the activity of molten iron,controlling the composition of CE and trace elements,selecting the appropriate inoculation agent and inoculation method,increasing the local cooling speed and reducing the hot section of casting can effectively prevent the problem of chunk graphite in heat-resistant nodular iron.
