Casting is the process of melting metal into a liquid that meets certain requirements and pouring it into the mold. After cooling, solidification and cleaning treatment, the castings with predetermined shape, size and performance can be obtained. Casting is one of the basic processes in modern manufacturing industry, which can reduce the cost and time to a certain extent because of the near forming of casting blank. After the casting is taken out from the casting mold cooled by pouring, there are gates, risers and metal burrs. The casting of sand casting also adheres to sand, so it must go through the cleaning process. The equipment for this kind of work includes shot blasting machine, gate riser cutting machine, etc. Sand casting cleaning is a process with poor working conditions, so when choosing the molding method, we should try to create convenient conditions for sand cleaning. Some castings need to be treated after casting due to special requirements, such as heat treatment, reshaping, antirust treatment, rough machining, etc.
Casting is a relatively economic method of blank forming, which can show its economy for the parts with complex shape. Such as the cylinder block and cylinder head of automobile engine, ship propeller and exquisite works of art. Some parts that are difficult to cut, such as nickel base alloy parts of gas turbine, cannot be formed without casting.
In addition, the size and weight of casting parts are widely used, and the metal types are almost unlimited; while the parts have general mechanical properties, they also have comprehensive properties such as wear resistance, corrosion resistance, shock absorption, etc., which other metal forming methods such as forging, rolling, welding, punching, etc. cannot do. Therefore, in the machine manufacturing industry, the number and tonnage of rough parts produced by casting method is still the largest.
The materials often used in foundry production include various metals, coke, wood, plastics, gas and liquid fuels, molding materials, etc. The required equipment includes various furnaces for smelting metal, various sand mixers for sand mixing, various molding machines and core making machines for molding and core making, sand dropping machines and shot blasting machines for cleaning castings, etc. There are also machines and equipment for special casting as well as many transportation and material handling equipment.
Casting production has different characteristics from other processes, such as wide adaptability, more materials and equipment, and environmental pollution. Foundry production will produce dust, harmful gas and noise pollution to the environment, which is more serious than other mechanical manufacturing processes, and measures need to be taken to control.
The development trend of casting products requires better comprehensive properties, higher precision, less allowance and cleaner surface. In addition, the demand for energy conservation and the demand of society for the restoration of the natural environment are also growing. In order to meet these requirements, new cast alloys will be developed, and new smelting processes and equipment will appear accordingly.
At the same time, the degree of mechanization and automation of foundry production is increasing, and it will develop to flexible production, so as to expand the adaptability to different batches and varieties of production. New technologies for saving energy and raw materials will be given priority, and new processes and equipment with little or no pollution will be given priority. The quality control technology will have a new development in the detection, nondestructive testing and stress measurement of each process.
Casting is one of the basic processes of modern mechanical manufacturing industry. As a kind of metal hot working technology, casting is gradually mature in China. Casting process is the process of melting metal into a certain liquid and pouring it into the mold. After cooling, solidification and cleaning treatment, the casting with predetermined shape, size and performance can be obtained.
Casting machines are generally classified according to the molding methods, which are usually divided into ordinary sand casting and special casting. Common sand casting includes wet sand casting, dry sand casting and chemical hardening sand casting. According to the difference of molding materials, the specialty can be divided into two categories: one is to use natural mineral sand as the main molding materials, such as investment casting, shell casting, negative pressure casting, mud casting, solid casting, ceramic casting, etc.; the other is to use metal as the main molding materials, such as metal casting, centrifugal casting, continuous casting, pressure casting, low pressure casting, etc.
The casting process can be divided into three basic parts: the preparation of casting metal, the preparation of casting mold and the treatment of casting. Cast metal refers to the metal material used for casting in casting production. It is an alloy composed of a metal element as the main component and other metal or non-metal elements. It is commonly known as cast alloy, mainly including cast iron, cast steel and cast non-ferrous alloy.
Casting process has different characteristics from other processes, such as wide adaptability, more materials and equipment, and environmental pollution. The foundry process will produce dust, harmful gas and noise pollution to the environment, which is more serious than other mechanical manufacturing processes, and measures need to be taken to control.
The development trend of casting products requires better comprehensive properties, higher precision, less allowance and cleaner surface. In addition, the demand for energy conservation and the demand of society for the restoration of the natural environment are also growing. In order to meet these requirements, new casting alloy will be developed, new casting process and new casting equipment will appear correspondingly.
