The pouring position of the casting refers to the position of the casting in the mold when pouring. This position has a great influence on the quality of the casting. So how to determine the pouring position of the valve casting?
1. The important processing surface or main working surface of the casting should face down or to the side, because the defects (such as blisters, pores, slag inclusions, etc.) on the upper surface of the casting are usually more than those in the lower part, and the structure is not as dense as the following. If the planes are difficult to get down, try to keep them on the side. When there are multiple important machined surfaces, the larger surface should be turned downward, and the upward surface should be increased by increasing the machining allowance to ensure the quality of the casting.
2. The large plane of the casting should face down. This is because during the pouring process, the high-temperature liquid metal has strong thermal radiation on the upper surface of the cavity, and sometimes the sand on the upper surface of the cavity arches or China Foundry Excavator Bucket Adapter
cracks due to rapid thermal expansion, resulting in sand inclusion defects on the surface of the casting. Obviously, the thicker the plane in the horizontal position is, the easier it is to produce sand inclusions on the upper surface. For this reason, for flat castings, the large plane should be facing down.
3. In order to prevent the large-area thin-walled part of the valve casting from causing insufficient pouring or cold insulation defects, the large-surface thin-walled part should be placed at the lower part of the casting mold or vertical and inclined, which is especially important for alloys with poor fluidity.
4. For castings that are easy to form shrinkage holes, the thick part should be placed on the upper or side near the parting surface during pouring, so that the riser can be directly placed in the thick part of the casting, so that it solidifies and replenishes in the order from bottom to top. shrink to prevent shrinkage.
The above four points can determine the pouring position of the valve casting. In order to ensure the quality of the casting, we must grasp this position.