Wind power flanges are cast parts, and are all high-demand ferritic ductile iron parts, which should have good tensile strength, elongation and stiffness, and also require a V-shaped incision at minus 20 ° C. The impact toughness averages 10J. The wind flange has high impact strength at low temperatures, and with the development of large-scale wind power generation equipment, the requirements are getting higher and higher, and large-sized castings having a shape more complicated by 300 mm or more are required.
The wind flange adopts the bottom injection casting system. In order to increase the punching speed and reduce the temperature difference of the cavity, we use two sprues; the furan resin self-hardening sand and the corresponding alcohol-based coating ensure the dimensional accuracy and surface quality; Position the core and check the template when the core is underneath to ensure dimensional accuracy. In order to ensure the strength of the sand and the amount of gas generated, the shape and core were made the day before, and the mold was fitted the next day.
Wind flanges are characterized by low temperature treatment and low temperature casting. They must have targeted composition considerations to delay the spheroidization decline and promote heterogeneous nucleation on the other hand. The rate of addition of the instantaneous inoculant is controlled according to the pouring time. In order to further ensure the quality of the wind flange, the process requires that a certain amount of excess molten iron overflows from the riser when pouring. The surface of the riser is then covered with a heat retaining agent. After the pouring is completed, the box is opened at 150-160 hours, that is, the casting temperature is about 250 ° C or lower.
After the wind flange is formed, it is necessary to remove the pouring riser, the parting surface and the core sipe, and at the same time sanding; the surface roughness of the wind flange should reach Ra12.5-25. After the cleaning process, the wind flange is cleaned and inspected by the inspector. The qualified mark is applied according to the specified color. The product library is responsible for checking the inspection mark of the imported casting. The unmarked or unmarked castings should be rejected.