Today’s wind power technology presents the trend of large-scale development. Larger units can make more intensive use of wind energy resources and land resources, reduce the number of units under a certain installed capacity, reduce the cost of foundation, operation and maintenance, lifting and other aspects, and lay the foundation for the larger development of wind power, especially in the development of offshore wind power. However, the large-scale unit also faces some new challenges. The demand for lightweight design brought by the increasing size of parts and components forces the manufacturing technology of ductile iron castings to improve, and it needs to constantly break through the performance limits of current materials and processes.
Hub, frame, rotor and main shaft are important components of large offshore wind turbines. Considering the large size, high power and harsh offshore operating environment of ultra-large offshore direct-drive wind turbines, as well as the transmission and support role of the main shaft in the engine room, higher requirements are put forward for the performance, surface quality and internal quality of ductile iron castings.
Through designing a reasonable gating and riser system, melting process, spheroidization and inoculation treatment process of ductile iron castings, using MAGMA numerical simulation software to assist in analyzing the filling and solidification process of molten iron, visually observing the flow rate and temperature field of molten iron, the ductile iron castings for the main shaft of large offshore wind turbines with high quality requirements have been successfully developed.