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How do the Riser Sleeves Solve the Casting Shrinkage
2022-05-24

The exothermic riser sleeves are now an integral part of foundry production. It can solve the casting shrinkage and provide feeding for castings. Do you know how the exothermic sleeves solve the casting shrinkage and provide feeding for the casting?

In the design process, the exothermic sleeve has the function of heat preservation. It can alleviate the impact of molten iron on the cavity. The exothermic sleeve should be able to provide enough heat for the riser neck. Make the riser neck have a high enough temperature to ensure that the riser neck will not solidify prematurely during the pouring process, to facilitate the rapid flushing of the molten iron. When designing the riser sleeve height, it is generally 1.2-1.3 times the height of the pattern, This ensures that it is higher than the feeding position, and the gate can remove easily.

exothermic riser sleeves

Use Cases of Exothermic Riser Sleeves:

At present, the riser neck position of a foundry is located at the end of the pipe fitting. The small parts have good punching and feeding effect, but the large parts have a poor feeding effect on the side corners of the gate. It is necessary to increase the number of blind riser sleeves to solve the problem. The reason for this is that the corners are inner corners. The heat dissipation conditions are poor. The heat dissipation is slow, so shrinkage is prone to occur.

Given the above analysis, the factory changed the pouring position from the end face to the corner. Without change the blind riser sleeve height, but add the ribs at the corner. Makes the blind riser sleeves easier to feed.

Trial Results:

According to the analysis, the 90° elbow is the inner angle, the heat dissipation condition is poor, the heat dissipation is relatively slow, and it is the largest hot spot of the pipe fittings. Therefore, this part is prone to shrinkage.

Because of the above analysis, the factory changed the pouring position from the end face to the corner in the process design, and the exothermic riser sleeve top was the same as the height of the pipe fittings in the upper form. In addition, ribs are added at the corners, which not only concentrates the hot joint area, making it easier for the riser sleeve to play the feeding role, and at the same time ensuring the maximum consistency in the shape of the pipe fittings.

The practice has proved that this process eliminates shrinkage defects. It can be extended to the process design of tee, cross, and inner and outer wire elbows, which can significantly improve the process yield and pass rate of pipe fittings.

Do you need exothermic riser sleeves? Sefu mainly produces various casting auxiliary materials. Sefu has many types of exothermic riser sleeves, complete specifications, and a good feeding effect. Come and leave your inquiry now.