QT450-12 is selected as the impeller material, and the overall dimension of the casting is 1450mm × 850 mm × 380 mm, weighing 1215 kg, the casting is required to undergo ultrasonic flaw detection (UT) and magnetic particle flaw detection (MT), and there shall be no visual defects after processing.
The horizontal and vertical pouring scheme of the mold is adjusted to the horizontal and horizontal pouring process scheme to avoid the sand box overturning after box closing, improve the box closing efficiency, and avoid the sand inclusion problem caused by the sand falling from the mold cavity during the overturning, as well as the fire problem caused by the vertical pouring; The problems of sand inclusion and slag inclusion in the large plane of the casting are solved by improving the cleanliness of the molten iron and the cavity, including the bottom pouring system, placing the filter, using the ceramic tube in the inner runner, and cleaning the local virtual sand in the cavity.
MAGMA solidification simulation software was used to simulate the distribution of shrinkage porosity in castings. According to the shrinkage porosity distribution, further adjust the arrangement of chill and riser to solve the shrinkage porosity defect of casting. Ultrasonic flaw detection and magnetic particle flaw detection are adopted for NDT. The flaw detection requirements are as follows: UT (DIN EN 12680-1Grade 1) and MT (DIN EN 1369 Grade SM 3) are qualified, and the machined surface is free of shrinkage defects.