Sand Casting Knowledge Point Summary

1. Principle of sand casting

Sand casting is done by pouring molten metal into a mold made of materials such as gypsum, clay, or silicone, and breaking the mold after the metal has solidified to obtain the desired casting. It is based on the principle of utilizing the softness and ease of molding of sand molds for metal casting by processing the internal cavities and external shape of the sand molds to obtain the desired castings.

2. Sand casting process flow

Sand casting process mainly includes mold preparation, pouring, solidification and cooling, demolding and other steps. The first is the preparation of the mold, usually using wet sand and dry sand type two ways. Then comes the pouring, where the metal is poured into the mold to fill the mold cavity. Then comes solidification and cooling. After the metal has completely solidified, the mold can be demolded and the casting can be removed from the mold for subsequent processing.

3. Different types of sand casting

According to the different molds, sand casting can be divided into two types: wet sand type and dry sand type. Wet sand refers to the mold preparation process, the use of wet clay or binder mixed into the mold sand, and then fill the mold sand into the mold, after molding, drying and other steps, the final formation of sand. Dry sand is the use of inorganic binder or organic binder and in the net of quartz sand mixed into the mold sand, after vibration, molding and other steps, the formation of molds.

4. Sand casting in the sand material

Sand casting in the use of sand materials are mainly quartz sand, river sand and other natural sand, as well as clay, gypsum and silicone resin and other binders. Quartz sand is the most commonly used sand material because of its fine, hard, and high-temperature resistance between particles. And the choice of binder depends on the requirements of the casting and the specific conditions of production.

5. Defects and quality control in sand casting

In sand casting, the common defects are mainly porosity, trachoma, inclusions, shrinkage holes and so on. The production of these defects is usually related to the preparation of sand mold, pouring process, metal solidification and so on. Therefore, the quality control of sand casting is crucial to the need for comprehensive management and control from the quality of raw materials, process parameters, operating techniques, equipment status and other aspects.

6. Sand casting application areas

Sand casting is widely used in a variety of mechanical parts, automotive parts, ship parts, aerospace parts and other fields due to its simple process, low cost, a wide range of applications, so it still has an important position in the manufacturing industry.

7. Sand casting in the technical points

In the process of sand casting, need to pay attention to some technical points to ensure the quality of castings. For example, in the mold preparation process, pay attention to the sand molding and drying, so as not to produce trachoma and porosity: in the pouring process, to control the temperature of the alloy and pouring speed, so as not to produce inclusions and shrinkage holes: in the process of solidification and cooling, to control the cooling rate, in order to ensure that the metal's organizational structure and properties.

In general, sand casting is an important metal working process, its process, technical points and quality control all play a decisive role in the final casting quality. Therefore, the research and mastery of sand casting can not only improve product quality and reduce production costs, but also promote the progress and development of metal casting process.