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2023.1.28
The metal with the symbol beginning with CAC indicates that it is a copper casting and a copper alloy casting. Similar to copper products, copper castings are divided into pure copper, brass, bronze, aluminum bronze, etc., which have common physical characteristics, but each has quite special properties, so they should be properly used according to the purpose.
Copper alloy is a kind of metal with excellent electrical conductivity, thermal conductivity, corrosion resistance, low temperature resistance, and other properties, but in addition to these properties, copper castings as copper castings also have properties that other castings do not have. It has been widely used in some industrial fields. Here we talk about everything you should know about copper casting.
Main uses and properties of copper alloy castings
One of the characteristics of copper alloy castings is that the pressure resistance is an important parameter, because it is often used in valves, cocks and other parts where water, oil and other liquids pass through. Equipment and components used to withstand hydraulic pressure, air pressure, water pressure, hot water pressure, etc., in addition to corrosion resistance and wear resistance, also need to withstand pressure. In addition, due to the review of water quality standards, which are commonly used in water-related materials, the leaching amount of lead is also considered as one of the parameters due to the recent environmental load and the impact on human body
It is usually used to predict conductivity and thermal conductivity, and has parameters that other metals except silver cannot catch up with.
It has good corrosion resistance, but it is worth noting that it is resistant to seawater. Aluminum bronze is particularly strong. In warm water, bronze is stronger than brass. When wear resistance is required, bronze is usually used.
Although the characteristics of copper castings vary from type to type, the focus of copper itself is the high conductivity and conductivity described above. In addition, most metals have the problem of low temperature brittleness, which will become brittle and deteriorate at low temperature. It is known that copper is not prone to this problem. Or, in terms of corrosion resistance, it has excellent seawater resistance, so it is also used in applications exposed to such environments. It is well known that even copper castings with the same characteristics (such as melting, casting and solidification) will vary from system to system.
Examples of characteristics of copper alloy castings
As mentioned earlier, the composition types of copper castings (various systems) are quite different, but if you list typical characteristics, such as the lead-containing bronze with the highest output. It has the following characteristics (although lead-free products have become more and more popular in recent years).
-Corrosion resistance
-Abrasion resistance
-Good machinability
-It is easy to make pressure castings with complex shapes
-Most suitable for low-pressure valves, medium-pressure valves, and cocks for hot water
This brand is sensitive to wall thickness, and its strength becomes weaker with the increase of wall thickness, so it is not suitable for structural materials and high pressure environment, but there are also types with excellent mechanical strength
In addition, it is said that lead has been added to improve the pressure resistance, machinability and lubrication effect, but in other countries such as RoHS Directive, even in Japan, there is also a movement to regulate the lead content. In order to reduce the use of lead, copper castings with limited lead content are also being developed.
Manufacturing method of copper castings and castings
The manufacturing methods of copper castings include sand casting, mold casting, continuous casting, centrifugal casting, die casting, and high-pressure casting, among which sand casting is the most common. Die casting is also used, but it is not used as often as aluminum die casting, because its melting point is very high and the mold is very painful.
The metal used as raw material is called gold bar. It can be new or renewable. Bronze castings and brass castings use a large amount of recycled metal, so they are easy to mix impurities, but have advantages in cost.
The cooling rate of copper castings is faster than that of aluminum, which will lead to poor hot water flow (molten copper cannot fully flow into the mold). However, in copper castings, aluminum bronze and brass belong to the category of good hot water fluidity. When the raw metal is melted into molten metal, the less oxide, the better the casting.
For copper castings, the casting method shall be determined according to each material. For materials designated for centrifugal casting, there are two modes: centrifugal casting with mold and centrifugal casting with sand mold. According to JIS standard, centrifugal casting of CAC502B, CAC503B and CAC903B is designated as using moulds.
Copper alloy castings and types of castings
Next, we will list the available casting types and their characteristics according to the “system”. The four systems of Cu-Sn, Cu-Zn, Cu-Al and Cu-Pb are the basis of copper alloys, and alloy elements are added to further distinguish the system. As for the elements contained as impurities, how each element affects each system will change, so it is necessary to check each system.
Pure copper base copper castings, castings
The higher the purity of copper, the stronger the trend. For overhead wire fittings, general electrical equipment parts, electrode rack, etc. CAC101, CAC102, CAC103 and other CAC100 series materials correspond to this.
Brass-based copper castings, castings
It is an alloy of zinc and copper. It is one of the main production materials of Jiaxing Gurun. It is used for various purposes such as metal fittings in brass products, but it has not been accidentally used in castings. In addition to the advantages of good castability and easy plastic processing, it also has excellent corrosion resistance and wear resistance. The price is low, and it is comparable to bronze in terms of electric conductivity and heat conduction. However, in Japan, the use of water-related parts and valves is small, and the demand is large. Therefore, compared with bronze castings, the use is very small (it is said that the water quality in Europe and America varies with the water quality). CAC201, CAC202, CAC203 and other CAC200 series correspond to this.
High strength brass base copper castings, castings
This type is made of brass-based material and is one of the main production materials of Jiaxing Gurun. This product is added with additives to further improve corrosion resistance and wear resistance. Propulsion devices and components for ships and ships. CAC301, CAC302, CAC303, CAC304 and other CAC300 series materials correspond to this.
Bronze mold copper castings, castings
It is a type with excellent castability, pressure resistance and corrosion resistance. It is also the main advantage material of Jiaxing Gurun. It has the characteristics of clean casting surface. However, in terms of performance, it is weaker than brass-based products in terms of conductivity and thermal conductivity, and lower than aluminum bronze and high-strength brass-based castings in terms of tensile strength and yield stress mechanical strength. CAC401, CAC402, CAC403, CAC406, CAC407, CAC408, CAC411 and other CAC400 series materials correspond to this.
Phosphor bronze copper castings, castings
It is a type of phosphorus added based on Cu-Sn base composition, aiming to improve strength, hardness and wear resistance. Compared with bronze castings, it has particularly excellent hardness. Due to the good fluidity of molten metal, it also has good wear resistance and excellent casting performance. CAC502A, CAC502B, CAC503A, CAC503B and other CAC500 series materials correspond to this.
Lead bronze copper castings, castings
The base is tin bronze with a large amount of lead added. Because of its excellent impact resistance, load resistance, friction and wear resistance, it is also used for embroidery parts. It is especially famous for its excellent sliding bearing, which is not easy to bite with each other during friction, and has excellent compatibility. It has requirements for corrosion resistance and low friction coefficient of lubricating oil. Friction and coefficient of thermal expansion are also materials that meet the requirements. CAC602, CAC603, CAC604, CAC605 and other CAC600 series materials correspond to this.
Aluminum bronze copper castings, castings
It is the type with the best mechanical strength and corrosion resistance. On the other hand, although hard, it is difficult to make complex shapes as a casting. The system is used for large propulsion devices such as ships and large components such as seawater desalination devices. The four types of CAC700 series, CAC701, CAC702, CAC703 and CAC704, correspond to this.
Sylzin bronze copper casting, casting
This type was developed as a substitute for tin bronze, but it has excellent strength and corrosion resistance. In addition, the molten metal has good fluidity, so casting can be used. It also applies to welding and brazing. CAC800 series such as CAC801, CAC802, CAC803 and CAC804 correspond to this.
Bismuth bronze base, bismuth selenium bronze base copper castings, castings
Due to the impact of lead on human body and environment, people have studied and developed how to use lead in bronze castings, which are most used in water supply systems. With the implementation of the new water quality standards, Japan will also limit the use of lead in parts in contact with water, and new castings using “bismuth” and “selenium” as alternative elements to replace lead have been born CAC900 series, namely CAC901, CAC902, CAC903B, CAC904, CAC911 and CAC912, correspond to this.