Principles of casting secondary cooling system design
The design of a casting secondary cooling system involves the management of several variables that work together to produce a satisfactory final product. The variables include the mould temperature, the cooling-water temperature, the pressure head, mass flow rate, and the velocity of the water flow. To ensure the best results, it is important to understand the principles governing the interaction of these variables, and to design the system in line with these principles.
The first principle of secondary cooling system design is the mould temperature control. This involves the selection of a material that can be cooled to the desired temperature. The material should be able to dissipate the heat generated during solidification of the casting, so that the casting does not become too hot. The amount of cooling required to achieve the desired temperature is often determined by the geometry and material of the pattern used in the casting process. When the pattern is too thin or of a material that is not suitable for cooling, the mould temperature should be reduced to ensure that the casting is not overheated.
The second principle is the control of cooling-water temperature. This is generally achieved by using chilled or cold water. The cooling-water temperature should be adjusted to match the mould temperature. If the temperature is too high, the mould will become hot due to the heat generated by the cooling water, and this could lead to an unsatisfactory casting. Conversely, if the temperature is too low, the mould will not be cooled adequately, resulting in an incomplete or inaccurate casting.
Thirdly, the pressure head of the cooling water is important. The flow of cooling water can influence the temperature of the mould surface. If the pressure head is too high, the water velocity will be too high, which will cause the cooling water to be hotter than the mould surface. This could lead to an uneven cooling process, resulting in an unsatisfactory casting.
Lastly, mass flow rate and velocity of the water flow are also important considerations. The mass flow rate should be kept at an appropriate level, as too little or too much can result in overheating or undercooling of the mould surface, respectively. The velocity of the water flow should also be adjusted to ensure that the water reaches all parts of the mould and creates a uniform, continuous cooling process.
In conclusion, there are several principles that must be kept in mind when designing a casting secondary cooling system. The mould temperature should be kept at an appropriate level, the cooling-water temperature should be adjusted to match the mould temperature, the pressure head should be appropriate, the mass flow rate and velocity of the water flow should be controlled, and the cooling water should reach all parts of the mould to ensure a uniform cooling process. Following these principles can help to ensure a satisfactory product is produced.
