Foundry - smelting of metal, manufacturing of casting mould, pouring of molten metal into casting mould, solidification of metal parts with a certain shape, size and performance of the blank forming method

Casting is the process of smelting metal into liquid which meets certain requirements and pouring it into the casting mold.Because the casting blank is nearly formed, the cost is reduced and the production time is reduced to a certain extent.Casting is one of the basic processes in modern plant manufacturing industry.

Casting classification

There are mainly sand casting and special casting 2 categories.

1 ordinary sand mold casting, using sand as the casting material, also known as sand casting, sand turning, including wet sand mold, dry sand mold and chemically hardened sand mold 3 categories, but not all sand can be used for casting.The advantage is lower cost because the sand used in the mold is reusable;The disadvantage is that the casting time, casting itself can not be reused, must be destroyed before the finished product.

1.1 sand mold (core) casting method: wet sand mold, resin self-hardening sand mold, sodium silicate sand mold, dry mold and surface dry mold, solid mold casting, negative pressure molding.

1.2 sand core manufacturing method: the sand core is selected according to its size, shape, batch production and specific production conditions.In production, from the overall can be divided into manual core and machine core.

2 special casting, press molding materials and can be divided into natural mineral sand as the main special casting molding materials (e.g., investment casting, mold casting, shell mold casting, pressure casting, mold casting, ceramic mold casting, etc.) and metal as the main mold material of special casting (such as metal mold casting, pressure casting, continuous casting, low pressure casting, centrifugal casting, etc.).

2.1 metal mold casting method

Molds are made of metals with a higher melting point than raw materials. It is subdivided into gravity casting, low pressure casting and high pressure casting.

The amount of metal that can be cast is limited by the melting point of the mold.

2.2 dewaxing casting method

This method can be used for outer membrane casting and solid casting.

The wax is then immersed in a pool containing ceramic (or silica sol) and allowed to dry. The wax replica is then coated with a ceramic coating. The process is repeated until the coating is sufficient to support the casting process (approximately 1/4 "to 1/8"). After the mold needs to be repeatedly to be high temperature, enhance the hardness of the rear can be used for casting.

This method has good accuracy and can be used for casting high melting point metals such as titanium. But because ceramics are expensive, and because they require multiple heats and are complex to make, they are expensive.