Causes of spheroidization and decline in the quality of ductile iron pipes

- Mar 12, 2021-

When manufacturing ductile iron pipes, pay attention to the quality of ductile iron pipes. What are the specific reasons for the unqualified spheroidization and decline? Let me give you a detailed introduction. After the ductile iron pipe is manufactured, there will naturally be some unqualified products, such as poor spheroidization and recession. So why do ductile iron pipes have poor spheroidization and decline? The price of ductile iron pipes the reasons for poor spheroidization and decline of ductile iron pipes: 

(1) The characteristic is that the silver fracture is covered with small black dots visible to human eyes. In addition, there are many small black spots, large diameter, and ductile iron pipes, indicating that the level of poor spheroidization is serious. When observing the microscope mechanism, in addition to spherical high-purity graphite, there are also many thick blocks of high-purity graphite. As a result, the physical properties cannot reach the index value required by the model, and the casting fee is reported. The price of nodular cast iron pipe

(2) The root cause is that the sulfur content in the original molten iron is too high or the molten iron is more severely oxidized; the content of nodularizing element is not enough (the amount of nodulizing agent is not enough, Insufficient water content of magnesium or serious shrinkage, excessively high temperature of molten iron, a large amount of spheroidizing agent ablated during solution; or solution temperature is low, spheroidizing agent adheres to the bottom of the bag, etc.); the molten iron has an effect Su exist and wait. 

(3) Avoidance countermeasures can adopt matching avoidance countermeasures. If the inspection in front of the furnace finds that the nodular cast iron pipe is not well spheroidized in the front of the furnace, a proper nodulizer should be added to the solution package immediately.