Casting is generally classified according to the modeli […]
Casting is generally classified according to the modeling method, and is customarily divided into ordinary sand casting and special casting. Ordinary sand casting includes three types: wet sand type, dry sand type and chemically hardened sand type. Special castings can be divided into two categories according to different modeling materials: one is natural mineral sandstone as the main modeling material, such as investment casting, shell casting, negative pressure casting, clay casting, solid casting, ceramics. Type casting, etc.; one type of metal is used as the main casting material, such as metal casting, centrifugal casting, continuous casting, pressure casting, low pressure casting, and the like.
The casting process can be divided into three basic parts, namely casting metal preparation, mold preparation and casting processing. Cast metal refers to the metal material used for casting castings in casting production. It is an alloy composed mainly of a metal element and added with other metal or non-metal elements. It is customarily called cast alloy, mainly cast iron. Cast steel and cast non-ferrous alloys.
Metal smelting is not only a simple melting process, but also a smelting process that allows the metal to be poured into the mold to meet the expected requirements in terms of temperature, chemical composition and purity. For this reason, various inspection tests for the purpose of controlling quality are carried out during the smelting process, and the liquid metal can be allowed to be poured after reaching various specified indexes. Sometimes, in order to achieve higher requirements, the molten metal is treated outside the furnace after being discharged, such as desulfurization, vacuum degassing, refining outside the furnace, gestation or deterioration treatment. Commonly used equipment for melting metal is cupola, electric arc furnace, induction furnace, electric resistance furnace, reverberatory furnace and the like.
Different casting methods have different mold preparation contents. Taking the most widely used sand casting as an example, the mold preparation includes two major tasks: modeling material preparation and modeling core making. Sand casting, various raw materials used for molding core, such as foundry sand, sand binder and other auxiliary materials, as well as molding sand, core sand, paint, etc., which are formulated by them, are collectively referred to as modeling materials. The task of preparing materials is to follow castings. The requirements, the nature of the metal, the selection of the appropriate raw sand, binder and auxiliary materials, and then they are mixed into a certain type of molding sand and core sand in a certain proportion. Commonly used sand mixing equipment include a roller type sand mixer, a counter flow type sand mixer and a blade groove type sand mixer. The latter is designed for mixed chemical self-hardening sand, continuous mixing and fast speed.