Purpose of Pipe Mold Powder: When producing ductile iron pipes, it will contain a certain amount of carbon, which will be tightly combined with iron, and the form of carbon in solidified cast iron is very important for the performance of the cast iron pipe. If the carbon is in the form of iron carbide, the cast iron is called white cast iron, which is hard and brittle and has poor practicality. If the carbon is in the graphite state, the cast iron is soft and easy to process. It is called gray cast iron and has strong practicability. Graphite state can be divided into flake, dense and spherical shape. The spherical shape can show the highest strength and most ductile cast iron. Therefore, during the solidification of cast iron, the auxiliary effect of additives is needed to make the ductile iron pipe achieve the desired effect. Usually, the spheroidization rate, the number of graphite balls and the pinhole rate of the ductile iron pipe are used to measure the quality of additives.