Defect optimization of sand casting coupling parts

The specific optimization measures are as follows: set annular external cold iron in sand core 2. The purpose of this is to use the chilling effect of cold iron to change the temperature distribution in the mold cavity of sand casting coupling parts, so as to transfer the hot joint parts in the thick section of the mold cavity of sand casting coupling parts to the outside as a whole, which is conducive to the feeding of ingate and riser. Then add a rectangular cold iron outside the convex part of the sand casting coupling parts, in order to make the rectangular cold iron and the annular cold iron in the sand core 2 work together to make the part solidify first under the chilling effect. The distance between the two ingates increases, and the angle and position of liquid metal into the mold cavity of sand casting coupling parts are changed, which is conducive to improve the temperature distribution in the mold cavity of sand casting coupling parts between the two ingates. In addition, as a last resort, it is necessary to abandon the strategy of introducing liquid metal into the upper plane of sand casting coupling parts, and introduce liquid metal from the part slightly above the middle of the mold cavity of sand casting coupling parts, so as to make the riser replenishment path closer to the hot joint and avoid direct superposition with the hot joint, In order to improve the feeding effect of riser and ingate on the last solidified part of sand casting coupling parts. However, this measure will change the position of parting surface and complicate the mold structure. It is also necessary to appropriately increase the riser size to ensure the effective liquid replenishment height. Here, the sprue height is not adjusted, because slightly reducing the pouring speed under the existing parameters will help to improve the molding quality of sand casting coupling parts. These optimization measures are major changes to the structure of the pouring and riser system. The above optimization measures have been optimized and tried for many times. Finally, the modified pouring El system is shown in Figure. In order to show the position of cold iron, the mold cavity of sand casting coupling parts on the right side of the tooling drawing is hidden.

Due to the great changes in the gating and riser system, the mold filling time changes greatly in this simulation. It is estimated that the time for liquid metal to fill the mold cavity of sand casting coupling parts will increase to 15.97 seconds. Because the main problem is that the probability of shrinkage porosity and shrinkage cavity is large, on the premise of ensuring the smooth filling of liquid metal, the pouring temperature is further reduced to 1350 degrees to reduce the liquid shrinkage and solidification shrinkage. In addition, the structure of annular cold iron and its combination with sand core 2 are complex. It is proposed to use the annular cold iron model to cast the blank, and then machine jjh-r cutting. In addition, the combination of annular cold iron and sand core 2 is pre embedded during core making, or in order to facilitate core making, the annular cold iron is directly flat with the upper plane of sand core 2, which will increase the production cost, However, in the current situation, it is only beneficial to the pouring results. Run anypre to complete the pre-processing and generate RLT file. After the calculation of anysolver module is completed, the optimization results are post processed and analyzed below.

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