(1) Low pressure casting (low pressure casting) Low pressure casting: refers to a method in which liquid metal is filled with a mold under a relatively low pressure (0.02 ~ 0.06 MPa) and crystallized under pressure to form a casting. Process flow: Technical features: 1. The pressure and speed during pouring can be adjusted, so it can be applied to a variety of different casting molds (such as metal molds, sand molds, etc.), casting various alloys and castings of various sizes; 2. Using bottom Injection type filling, the molten metal filling is stable, without splashing, which can avoid the entrapment of gas and the erosion of the wall and core, which improves the qualification rate of the casting; 3. The casting crystallizes under pressure, and the structure of the casting is dense and the outline Clear, smooth surface, high mechanical properties, especially beneficial to the casting of large and thin-walled parts; 4. Eliminate the need for feeder risers, and increase the metal utilization rate to 90-98%; 5. Low labor intensity, good working conditions, and equipment Simple, easy to realize mechanization and automation. Application: Mainly traditional products (cylinder head, wheel hub, cylinder frame, etc.).
(2) Centrifugal casting: Centrifugal casting is a casting method in which molten metal is poured into a rotating mold, and the mold is filled under the action of centrifugal force to solidify and shape. Process flow: Process characteristics and advantages: 1. There is almost no metal consumption in the pouring system and riser system, which improves the process yield; 2. The core can be omitted when producing hollow castings, so it can be greatly improved when producing long tubular castings. Improve metal filling ability; 3. Castings have high density, less defects such as pores and slag inclusions, and high mechanical properties; 4. It is convenient to manufacture barrel and sleeve composite metal castings. Disadvantages: 1. There are certain limitations when used in the production of special-shaped castings; 2. The diameter of the inner hole of the casting is inaccurate, the inner hole surface is relatively rough, the quality is poor, and the machining allowance is large; 3. The casting is prone to segregation of specific gravity. Application: Centrifugal casting was first used to produce cast pipes. At home and abroad, centrifugal casting is used in metallurgy, mining, transportation, irrigation and drainage machinery, aviation, national defense, automobile and other industries to produce steel, iron and non-ferrous carbon alloy castings. Among them, the production of castings such as centrifugal cast iron pipes, internal combustion engine cylinder liners and shaft sleeves is the most common.