1  Cast aluminum alloy;Properties and Applications of Aluminum Alloys  The density of cast aluminum alloy is lower than that of cast iron and cast steel, while the specific strength is higher. Therefore, using aluminum alloy castings under the same load conditions can reduce the weight of the structure. Therefore, aluminum alloy castings are widely used in the aviation industry, power machinery, and transportation machinery manufacturing.Aluminum alloy has good surface gloss and good corrosion resistance in the atmosphere and fresh water, making it widely used in the manufacturing of civilian utensils. Pure aluminum has good corrosion resistance in oxidizing acid media such as nitric acid and acetic acid, so aluminum castings also have certain applications in the chemical industry. Pure aluminum and aluminum alloys have good thermal conductivity, and are suitable for manufacturing heat exchange devices used in chemical production, as well as parts that require good thermal conductivity in power machinery, such as cylinder heads and pistons of internal combustion engines.Aluminum alloys have good casting properties. Due to its low melting point (pure aluminum has a melting point of 660.230C, and the pouring temperature of aluminum alloys is generally around 730-750oC), casting methods such as metal mold and pressure casting can be widely used to improve the internal quality, dimensional accuracy, surface smoothness, and production efficiency of castings. Due to the high solidification latent heat of aluminum alloy, under the same weight conditions, the solidification process of aluminum liquid lasts much longer than that of cast steel and cast iron, and has good flowability, which is conducive to casting thin-walled and structurally complex castings.Classification and grades of cast aluminum alloyAluminum alloys are divided into two categories according to different processing methods, namely pressure processed aluminum alloys and cast aluminum alloys (represented by YL and ZL respectively). In the cast aluminum alloy, it is divided into four series based on the main alloying elements added, namely cast aluminum silicon alloy, cast aluminum copper alloy, cast aluminum magnesium alloy, and cast lead zinc alloy (represented by ZL1X X, ZL2X X X, ZL3X X, and ZL4X X, respectively). In each series, it is further divided into several grades according to the chemical composition and properties. The following table lists the grades of several aluminum alloys included in the national standard for cast aluminum alloys. & nbsp;& nbsp; List of grades for cast aluminum alloys & nbsp;& nbsp; Serial Number; Alloy grade; Alloy code; Serial Number; Alloy grade; Alloy code; Serial Number; Alloy grade; Alloy code& nbsp;& nbsp;& nbsp;& nbsp; 1 ZALSi7Mg  ZL101  10  ZALSi12 Cu1Mg1Ni1  ZL109  19  ZALCu5MnCdA  ZL204A & nbsp;& nbsp;& nbsp;& nbsp; 2 ZALSi7MgA  ZL101A  11  ZALSi9Cu2Mg  ZL111  20  ZALCu5MnCdVA  ZL205A & nbsp;& nbsp;& nbsp;& nbsp; 3 ZALSi12  ZL102  12  ZALSi7Mg1A  ZL114A  21  ZALR5Cu3Si2  ZL207 & nbsp;& nbsp;& nbsp;& nbsp; 4 ZALSi9Mg  ZL104  13  ZALSi5Zn1Mg  ZL115  22  ZALMg10  ZL301 & nbsp;& nbsp;& nbsp;& nbsp; 5  ZALSi5Cu1Mg  ZL105  14  ZALSi8MgBe  ZL116  23  ZALMg5Si1  ZL303 & nbsp;& nbsp;& nbsp;& nbsp; 6  ZALSi5Cu1MgA  ZL105A  15  ZALCu5Mn  ZL201  24  ZALMg8Zn1  ZL305 & nbsp;& nbsp;& nbsp;& nbsp; 7  ZALSi8Cu1Mg  ZL106  16  ZALCu5MnA  ZL201A  25  ZALZn11Si7  ZL401 & nbsp;& nbsp;& nbsp;& nbsp; 8  ZALSi7Cu4  ZL107  17  ZALCu10  ZL202  26  ZALZn6Mg  ZL402 & nbsp;& nbsp;& nbsp;& nbsp; 9  ZALSi12Cu2Mg  ZL108  18  ZALCu4  ZL203 & nbsp;& nbsp;& nbsp;　　2  Cast copper alloy;Cast copper alloy is a widely used casting alloy material in industry. Copper based alloys are widely used in shipbuilding and chemical industries due to their excellent corrosion resistance to freshwater, seawater, and certain chemical solutions. Copper based alloys, due to their excellent thermal conductivity and wear resistance, are also commonly used in the manufacturing of sliding bearing shells and sleeves for bearing heavy loads and high-speed running shafts on various machines.Cast copper alloys are divided into two categories, namely brass and bronze. Brass is a copper alloy with zinc as the main alloying element. In casting brass, manganese brass, aluminum brass, silicon brass, lead brass, etc. are formed by adding other alloy elements. In copper alloys, those that do not primarily add elements such as zinc are collectively referred to as bronze, such as tin bronze, aluminum bronze, lead bronze, beryllium bronze, etc. According to national standards, there are a total of 9 types and 29 grades of cast copper alloys.　　3  Other non-ferrous alloys;In addition to cast aluminum alloys and cast copper alloys, there are also many types of cast non-ferrous alloys. The commonly used ones are cast magnesium alloys, cast titanium alloys, and cast zinc alloys. Magnesium and titanium alloys are commonly used in the aviation industry due to their high specific strength. Titanium alloy also has strong corrosion resistance to various corrosive media, so it is also used to manufacture castings that undergo corrosion in petrochemical equipment. Zinc alloys have high strength and excellent casting properties, making them widely used in the manufacturing of thin-walled and structurally complex castings.In terms of casting methods, copper alloys and other non-ferrous alloys not only use sand casting, but also widely use various special casting methods such as metal mold casting, centrifugal casting, low-pressure casting, and graphite mold casting.In copper alloy casting, the use of metal mold casting method to accelerate alloy solidification plays an important role in improving casting quality and reducing casting defects. Metal mold casting can subdivide grains (especially for aluminum bronze and manganese brass), reduce porosity, improve the mechanical properties and airtightness of the alloy (especially important for tin bronze). In high lead content copper alloys such as lead bronze, using metal mold (as well as water-cooled metal mold) casting can prevent segregation of copper components. Due to the large number of cylindrical parts (bearings, bushings) in copper alloy castings, centrifugal casting methods are commonly used. In addition, large copper castings (such as large marine propellers) can also be cast using low-pressure casting methods to improve the density of the alloy and reduce inclusions generated during the casting process. Some copper alloys (such as lead brass) can also use pressure casting methods.Due to the poor casting performance of magnesium alloys, especially their susceptibility to hot cracking, most magnesium alloy castings are still cast in sand mold. Only a small number of castings with simple shapes can be cast in metal mold. The pressure casting method is rarely used in magnesium alloy casting.Zinc alloy has excellent casting performance, strong filling casting ability, and does not produce hot cracks, making it particularly suitable for using metal molds and pressure casting. Pressure casting methods are commonly used in mass production to produce thin-walled and structurally complex zinc alloy castings.Due to its strong chemical activity, titanium alloys interact with most mold materials (including various sand and steel) during the casting process, resulting in contamination of the castings. Therefore, special mold materials such as thorium oxide or graphite can only be used for casting.　　4  Melting of cast non-ferrous alloys;The melting process has a significant impact on the properties and defects of non-ferrous alloy castings. Most non-ferrous alloys are prone to porosity and inclusions, especially titanium alloys, aluminum alloys, magnesium alloys, and certain copper alloys. The general smelting process is:1) According to the alloy grade specified in the casting technical requirements, the chemical composition range of the alloy can be found and selected from it;2) According to the burning loss rate and composition requirements of the elements, perform ingredient calculation, determine the amount of various furnace materials added, and select furnace materials. If the furnace material is contaminated, it needs to be treated to ensure that all furnace materials are clean and rust free, and preheated before feeding;3) Inspect and prepare equipment, apply paint, and preheat to prevent contamination by gases, inclusions, and harmful elements;4) Feeding. The general feeding sequence is: returning material, intermediate alloy, and metal material. Low melting point and easily oxidized metal materials, such as magnesium, are added after the furnace material melts;5) In order to reduce the pollution caused by suction and oxidation of the alloy liquid, it should be melted as soon as possible to prevent overheating. Some alloy liquids need to be protected with a covering agent as needed;6) After the furnace material is melted, refining treatment is carried out to purify the alloy liquid, and the refining effect is inspected;7) According to needs, carry out modification treatment and subdivision of organizational treatment to improve performance, and verify the treatment effect;8) Adjust the temperature for pouring. Some alloys need to be stirred before pouring to prevent specific gravity segregation.