Wind power foundries are still niche enterprises nationwide, and wind power castings have strict requirements for both casting and machining. This is always the case in the market: well-made wind power castings are in short supply, and foundries with poor product quality have no business all year round!
The base of the wind power equipment, the hub of the device blade, the gear box, the mechanical stand, etc. are all castings, and they are all ferritic ductile iron parts with high requirements, and their materials should have good tensile strength and elongation. It also requires the impact toughness of the Charpy V -notch at minus 20 ℃ to be 10J on average .
Wind power equipment castings must have high impact strength at low temperatures, and with the development of large-scale wind power equipment, the requirements are getting higher and higher, requiring more than 300mm thick large castings with more complicated shapes . The chemical composition, microstructure and mechanical properties of castings used in wind power generation equipment must be fully controlled.
For this reason, the silicon and phosphorus should be adjusted to be very low, the content of alloying elements should be low, and the spheroidization rate should be high. Its components must undergo strict ultrasonic testing, magnetic particle testing and color penetrant testing. The hub of the blades of the device should be tested by taking out the sample from the casting body when the threaded hole is opened, so the control should be carefully controlled during the production process.
In the production of ductile iron castings for wind power generation, it is very necessary to choose high-purity raw materials. The content of Si , Mn , S , and P in the raw materials is less. For some alloys such as Cu , Cr , Mo , Ti , Sn , V , and W. The content of the elements must be strictly controlled. All parts of the casting shall be inspected by magnetic particle inspection and ultrasonic inspection. The defects are not allowed to exceed the specified standard level; the appearance, roughness, non-metallic inclusions, pores, etc. of the casting shall not exceed the specified value range.
The spheroidizing agent adopts a mixture of rare earth spheroidizing agent DY-7B and 48% Elkem 5800 low silicon light rare earth; adopts silicon barium inoculant, uses Ba - containing anti-decay in front of the furnace , long-lasting inoculant, and special use when pouring. The inoculant of the composition is mainly the application of surface active elements. When applied to wind power castings, a proper amount of Bi element is added to improve the spheroidization of the central part of the section, making the ball diameter small, the number of balls, and the iron content The body content improves the as-cast performance.