Casting of 5 MW Wind Power Input Hollow Shaft Casting

The author develops and produces 5 MW wind turbine castings for a domestic customer, of which the input hollow shaft of JF050.04.27 is the key part of the unit. The chemical composition and mechanical properties of the castings are required to comply with DIN EN 1563 standard, the ultrasonic testing is up to grade 2 of DIN EN12680-3:2003 standard, and the magnetic particle testing acceptance is carried out according to EN 1369:1996 standard.

The input hollow shaft is a large revolving body, with the casting profile size of_2 590 mm x 2 050 mm, material number QT400-18AL, casting mass of 9 400 kg, main wall thickness of 90 mm, maximum wall thickness of 195 mm at bottom flange, minimum wall thickness of 30-40 mm at middle_2 430 mm large ring. There are 5 structural hot joints in the casting. The casting structure and the distribution of hot joint circles are shown in the figure.

(1) Input hollow shaft castings are molded with split ring and large core shell is made of steel and wood structure, which can prevent sand mold from deforming and ensure casting size.The solidification process of castings can be regulated by using cold iron reasonably in hot-spot area of castings and combining with heat insulation riser process to achieve the purpose of balanced solidification of molten iron.

(2) Foam ceramic filter is used on single gate with bottom pouring and open pouring system and funnel filter. Overflow risers are layered on the casting, which can purify molten iron, collect slag, heat and exhaust gas.

(3) The smelting process is strictly controlled and CE is controlled to over 4.4%, of which the median of w(C) is 3.7% and w(Si)>2.1%, which ensures the metallographic structure and mechanical properties of the castings.