Thermal simulation method for researching solidification process of ductile iron pipe based on heat transfer similarity of characteristic unit of ductile iron pipe

Centrifugal casting of ductile iron pipe is a high-temperature, semi-continuous production process. However, conducting laboratory research on the solidification process of centrifugal casting of ductile iron pipe presents significant challenges. In this study, a novel research method was introduced for investigating the solidification process of ductile iron pipe, namely thermal simulation of ductile iron pipe. Comparative research was conducted on the microstructure and properties of the thermal simulation sample and the ductile iron pipe. The findings indicate that the thermal simulation sample and ductile iron pipe exhibit good heat transfer similarity and microstructure similarity. The difference of cooling rate between thermal simulation sample and ductile pipe is less than 0.24 °C·s−1, and the difference of microstructure content of free cementite, ferrite, and pearlite is less than 5%. The tensile strength of annealed ductile iron pipe is 466 MPa, with an elongation of 16.1% and a Brinell hardness of 156.5 HBW. In comparison, the tensile strength of annealed thermal simulation sample is 482.0 MPa, with an elongation of 15.5% and a Brinell hardness of 159.0 HBW. These results suggest that the thermal simulation experimental research method is both scientific and feasible, offering an objective, reliable, and cost-effective approach to laboratory research on ductile iron pipe.