With the deepening understanding of the environment around the world and the maturity of renewable energy comprehensive utilization technology, the global wind power industry has developed rapidly in recent years. The development of offshore wind power is one of the effective measures to effectively utilize wind energy resources and alleviate the pressure of energy and environment in the southeast coastal areas of China. It has become a new trend and new growth point of the wind power industry and the main battlefield of the wind power industry in the next 10 years. Hub casting is a key part of wind power, which belongs to moving parts, and the operating environment is bad, so it has strict requirements on the quality of castings. Therefore, in the production process of hub casting, there are high requirements on the suitability and guarantee of casting process.
The liquid weight of wind turbine wheel hub casting varies from 10 tons to more than tens of tons. In process design, for different casting wall thickness and structure, a reasonable CE value can be designed to ensure dense and good castings. In order to avoid shrinkage defects caused by low CE value and graphite floating defects caused by high CE value. Generally, the CE value of wind power hub casting is close to the eutectic composition, that is, the content of C element in raw molten iron is controlled at 3.7% ~ 3.9%, and the content of Si element in casting is controlled at 1.7% ~ 2.2%.
(1) The process scheme with the main shaft hole facing up or down is generally adopted for wind turbine hub castings. With the large-scale development of Hub Castings, the scheme with the main shaft hole facing up is generally adopted, but the riser and cold iron shall be reasonably selected for feeding balance in thick parts.
(2) With the requirements of high-quality development, in order to ensure the internal quality of wind power Hub Castings, the filtering system is generally designed in the gating system, and the gating system with large flow, low flow rate and no turbulence is selected at the same time.
(3) According to the development concept of high strength, thin wall and lightweight in the future, in order to reduce the wall thickness of castings, achieve the purpose of cost reduction, efficiency increase, energy conservation and emission reduction. Further improve the tensile strength and yield strength of wind power castings. Higher grades such as QT 500-14 materials have been applied in wind power castings.