Determination method and pouring technique of pouring surface in precision casting

The position of casting in the mold affects the quality, dimensional accuracy and molding process difficulty of precision casting. Selection principle of pouring position:

1. The important processing surface or main processing surface of precision casting is downward or located on the side: during pouring, the gas, slag in the molten metal and sand particles in the mold will float up, which may cause the defects such as air hole, slag inclusion and sand hole in the upper part of the casting, while the structure is dense under the possibility of defects in the lower part of the casting.

a. The pouring position of machine tool bed should face down to ensure the quality of the important working face. The quality requirements of the circumferential surface are high. The vertical pouring scheme can make the circumferential surface at the side and ensure the uniform quality.

2. The large plane of the precision casting is poured downward or inclined: due to the intense heat radiation of the hot molten metal to the upper part of the mold, the sand mold on the top surface will expand and arch up or even crack, resulting in sand inclusion, sand hole and other defects on the large plane. The casting defects of large plane can be avoided by pouring with the large plane downward or by inclined pouring.

3. The thin wall of precision casting is downward, side standing or inclined: in order to prevent the cold shut and casting defects in the thin-walled part of the casting, the thin-wall with larger area should be placed at the lower part of the casting, or at the side wall or inclined position.

4. Most of the thickness of the precision casting should be placed on the top or on the side of the parting surface. The main purpose is to place the riser at the thick part for feeding.

In the casting process, the position of the casting in the mold will affect the quality of stainless steel precision casting, dimensional accuracy and the difficulty of forming process. The selection principle of casting position: the important machining surface or main processing surface of precision casting faces down or side: during pouring, gas in molten metal, slag and sand in mold will float.

Defects such as holes, slag inclusions and bubbles may be caused in the upper part of the casting, and the microstructure is dense under the possibility of defects in the lower part of the casting.

The large plane of stainless steel precision casting is toppled or inclined: due to the strong thermal radiation of molten metal on the upper part of the mold, the sand shaped expansion arch at the top causes sand and sand hole defects on the large plane. Large plane down or inclined casting method can prevent casting defects in mass production.

Thin wall of precision casting is downward, lateral or inclined: in order to prevent the cold partition wall of the thin-walled part of the casting from pouring in or not falling out, the thin-walled wall with larger area should be placed in a part of the lower part of the casting or in the lower part of the casting. Sidewall or inclined position. Most of the thickness of the precision casting should be placed on the top or side of the parting surface. The main purpose is to facilitate the riser into the thick wall section.