There are various methods for valve casting, each with its specific application scenarios and advantages and disadvantages. The following are some main valve casting process methods and their characteristics:

1. Sand casting

Sand casting is one of the most commonly used methods in valve casting. It uses materials such as sand, aggregates, binders, and water to make molds. The specific steps include:

Produce a template based on the external dimensions of the valve.

Embed the template into the sand box and pour in the evenly mixed sand, aggregate, and binder.

Tightly connect the sand through compaction and vibration, and fill the cavity.

After the sand solidifies, take out the template and obtain the sand mold for the valve.

Pour the molten metal into the sand mold and wait for it to cool and solidify before removing the casting.

The advantages of sand casting are low cost, flexible process, and suitability for valves of various shapes and sizes. However, its disadvantages are also quite obvious, such as relatively low dimensional accuracy and surface smoothness, and castings may require subsequent processing.

2. Metal mold casting

Metal mold casting is a high-precision casting method suitable for valves that require high dimensional accuracy and surface smoothness. Metal molds are generally made of materials such as aluminum alloy, bronze, or steel, and have the characteristics of high temperature resistance and wear resistance. During the casting process, molten metal is injected into the metal mold, cooled and solidified to obtain the casting.

The advantage of metal mold casting is that it can produce castings with high dimensional accuracy, good surface smoothness, and high production efficiency. However, the manufacturing and maintenance costs of metal molds are high, and they are not suitable for small batch production or complex shaped castings.

3. Resin sand casting

Resin sand casting uses resin as a binder and sand as aggregate to make molds. This process has good strength and plasticity, and is suitable for producing various types of castings. The advantages of resin sand casting are its short production cycle, low cost, and ability to adapt to the casting needs of valves of different sizes and shapes. However, similar to sand casting, its dimensional accuracy and surface smoothness may be relatively low, and the castings may require subsequent processing.

4. Film coated sand casting

Film coated sand casting is a process used for precision casting. Its characteristic is to coat a layer of film coated sand on the surface of the sand mold, forming a thin film. This type of film can improve the accuracy and surface smoothness of castings. Film coated sand casting is suitable for small valve castings with complex shapes and requiring high precision. However, its high cost and long production cycle may not be suitable for mass production.

5. Lost wax casting

Lost wax casting is a precision casting process suitable for valve castings with complex shapes and high precision. This process first produces a wax model, which is then covered with mortar and dried and baked. Afterwards, the wax model is melted to form a mold cavity, and the molten metal liquid is injected into the mold cavity. After the metal liquid cools and solidifies, the casting is obtained by demolding. The advantage of lost wax casting is that it can produce complex shaped castings with high dimensional accuracy and good surface smoothness. However, its production cost is high and the production cycle is long.

6. Gypsum casting

Gypsum casting is a casting method that uses gypsum as the casting material. This process is suitable for manufacturing valve castings with complex shapes. The advantage of gypsum casting is that it can produce castings with high precision and high surface finish, but its application range and output may be relatively limited.

Summary

When choosing the valve casting process, it is necessary to comprehensively consider factors such as the shape, size, surface finish requirements, and production batch of the valve. Different casting processes have their own advantages and disadvantages, and the most suitable process method should be selected according to specific needs. Meanwhile, it is also necessary to pay attention to controlling various parameters and conditions during the casting process to ensure that the quality and performance of the castings meet the requirements.