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Directional crystallization of a valve casting, crystallization under pressure, and hot gravity casting

Jun 08, 2018

In the process of manufacturing the pump valve casting, the wall thickness is thin, the type is complex, and the inner cavity needs to be formed. The solidification simulation technology is used to simulate and optimize the casting process parameters of castings and realize the casting of pump valves. Iron sand casting production. The production line adopts iron-free precision signal transmission technology, iron type heating system, high-efficiency hydraulic cleaning system, modular control system, independent circulating gating system, etc., and realizes the automatic and flexible production of cast iron type sand-cladding for pump valve castings.

  

Pump valve casting design elements

1. The internal and external sides of the pump valve castings and the ribs, etc., must have a certain degree of structural inclination in the direction of die-cutting to a certain extent.

2. The convex part of the casting of the pump valve should not be too different from the casting body. It is better to take the same height. Several bosses on the same surface are closer together, and it is better to connect the convex parts together.

3. The shape of the casting should be simple and easy to mold, so the casting parting surface should be as flat as possible, and the number should be the smallest.

4. The pump valve casting should try to avoid having a large level of water in the casting.

5. The casting hole in the plane wall of the pump valve casting should be reinforced with a kerf to reduce the wall thickness.

6. The casting structure should be able to shrink unhindered as much as possible when cooled.

7. There should be several connecting columns in the large-area sandwich chambers such as waterways and gas lines in the castings.

  

Directional crystallization of pump valve castings

  

Some investment castings such as turbine blades, magnetic steels, etc., if their crystal structure is columnar crystals arranged in a certain direction, their working performance can be improved a lot, so investment casting oriented crystallization technology is rapidly developing.

  

Crystallization of pump valve casting under pressure

  

Put the shell in the pressure tank and cast it. After the end, immediately close the pressure tank and introduce high-pressure air or inert gas into the tank to make the casting solidify under pressure to increase the density of the casting.

  

Hot gravitational pouring

  

This is the most widely used form of pouring, i.e., the shell is poured from the roaster and poured at high temperatures. At this time, the metal is cooled slowly in the mold shell, and the mold can be filled with high fluidity. Therefore, the casting can well replicate the shape of the cavity and improve the accuracy of the casting. However, the slow cooling of the casting in the hot type causes coarse grains, which reduces the mechanical properties of the casting. In the casting of carbon steel castings, the surfaces of slower cooling castings are also susceptible to oxidation and decarburization, which reduces the surface hardness, finish and dimensional accuracy of the castings.http://www.pump-casting.com/