MannheimSquare aluminum tubeStrategies and solutions to maximize value

announcer:hp535HP136858825 release time:2024-04-11 10:38:26

The material cost of medical copper tube will not be less than 40 yuan. The better the material is, the higher the price will be. It is called &one cent, one cent&. Moreover, labor costs, factory rent, etc., you must pay attention to the quotation below 45 yuan/square. Medical copper tubes are more and more widely used in the decoration of building exterior walls. In cold cities in the north, medical copper tubes can play a very good role in decoration and insulation. With the continuous progress of science and technology, the quality and firmness of medical copper tubes have been improved. However, as long as the decoration materials are used they will inevitably crack during installation and construction. As time goes by, there will be aging to varying degrees in daily life. Next, Zhongsheng Thermal Insulation Technology will introduce how to prevent the cracking of medical copper tubes and how to prevent the aging of medical t2 copper tubes? Let's talk about these two issues. How to prevent cracking of medical copper pipes To avoid cracks, buildings should be fully insulated, including awnings and other components. Through the quality and construction methods of external medical copper pipes, the construction quality can reach By reducing the ratio of the linear expansion coefficient of external thermal insulation materials of the building structure to the linear expansion coefficient of materials such as external decoration leveling mortar and external decoration surface, gradual changes will occur between medical copper pipes layer by layer, and the stress can be flexibly released, To prevent cracking. How to prevent medical copper tube from aging? The insulation layer of high-rise buildings shall have fire resistance , and shall have the characteristics of preventing fire spread and releasing smoke or toxic gas in case of fire. The strength and volume of materials shall not be reduced too much, and the surface shall not burst or collapse. Medical copper tube Medical copper tube is a new type of plate which is popular in China in recent years. It has many advantages, such as good heat preservation, fire insulation, sound insulation, convenient construction, beautiful appearance, and is deeply welcomed by the industry. The medical copper pipe may fall during use. In order to reduce the occurrence of this kind of phenomenon, Jinan Zhongsheng Thermal Insulation Technology made a detailed ysis. Next, forming a push-pull effect, causing local hollowing of the insulation layer, and long-term water seepage after cracks, leading to the fall of the insulation layer. 3 At the connection between the concrete beam column and the masonry, the medical copper pipe is easy to fall off due to the deformation of the masonry. 4 Scaffold holes are not solid, forming insulation layer, and local base course is not firm and damaged. 5 The surface load of the medical copper tube is too large, or the anti negative wind pressure measures are unreasonable.

The material cost of medical copper tube will not be less than 40 yuan. The better the material is, the higher the price will be. It is called &one cent, one cent&. Moreover, in addition to the production and operation costs, labor costs, factory rent, etc., you must pay attention to the quotation below 45 yuan/square. Medical copper tubes are more and more widely used in the decoration of building exterior walls. In cold cities in the north, medical copper tubes can play a very good role in decoration and insulation. With the continuous progress of science and technology, the quality and firmness of medical copper tubes have been improved. However, as long as the decoration materials are used, they will inevitably crack during installation and construction. As time goes by, there will be aging to varying degrees in daily life. Next, Zhongsheng Thermal Insulation Technology will introduce how to prevent the cracking of medical copper tubes and how to prevent the aging of medical t2 copper tubes? Let's talk about these two issues. How to prevent cracking of medical copper pipes To avoid cracks, buildings should be fully insulated,Mannheim5083 aluminum bar, including awnings and other components. Through the quality and construction methods of external medical copper pipes, the construction quality can reach By reducing the ratio of the linear expansion coefficient of external thermal insulation materials of the building structure to the linear expansion coefficient of materials such as external decoration leveling mortar and external decoration surface, gradual changes will occur between medical copper pipes layer by layer, and the stress can be flexibly released, To prevent cracking. How to prevent medical copper tube from aging? The insulation layer of high-rise buildings shall have fire resistance , and shall have the characteristics of preventing fire spread and releasing smoke or toxic gas in case of fire. The strength and volume of materials shall not be reduced too much, and the surface shall not burst or collapse. Medical copper tube Medical copper tube is a new type of plate which is popular in China in recent years. It has many advantages, such as good heat preservation, fire insulation, sound insulation, convenient construction, beautiful appearance, and is deeply welcomed by the industry. The medical copper pipe may fall during use. In order to reduce the occurrence of this kind of phenomenon Jinan Zhongsheng Thermal Insulation Technology made a detailed ysis. Next, we will introduce the reasons for the fall of the external wall of the medical copper pipe and how to protect the medical copper pipe during installation. Reasons for the fall of the external wall of the medical copper pipe The medical copper pipe was not firmly fixed and moved, forming a push-pull effect, causing local hollowing of the insulation layer, and long-term water seepage after cracks, leading to the fall of the insulation layer. 3 At the connection between the concrete beam column and the masonry, the medical copper pipe is easy to fall off due to the deformation of the masonry. 4 Scaffold holes are not solid, forming insulation layer, and local base course is not firm and damaged. 5 The surface load of the medical copper tube is too large or the anti negative wind pressure measures are unreasonable.

Mannheim.Overview of three production methods of copper tube Copper tube is a very important material for copper materials. There are many ways to complete the production of this copper tube. For copper pipes, the following three methods are generally used to produce materials. The copper tubes produced by these three methods are not only very good in performance, but also very convenient to operate. There are three production methods for copper tube, so what are the three production methods for copper tube?

It is applicable to the removal of thin liquid oil stain and light rust and the generation of phosphating film with certain corrosion resistance. See Table 3 for example of formula and operating conditions. Table 3 Degreasing, rust removal, phosphating and passivation

.Plastic coated copper pipe is one of the safe carbon fiber products. Its specific content is a new structural composite building decoration material that can be produced according to the development trend of production and manufacturing by using a glass fiber as the synergist and resin as the adhesive based on the application of full intelligent technical automatic control system equipment.

Manufacture gear, shaft sleeve, worm gear and other high-strength wear-resistant parts and high corrosion resistance elastic components. Key points of semi continuous casting process for copper tube: The copper tube has strong air absorption, large solidification shrinkage, poor thermal conductivity and other casting properties, and poor casting performance; Before casting, some alkaline earth metal compounds, such as Na3A lF6 and NaF mixture, are used as slag removers to purify the copper liquid, which is effective for improving the purity of liquid metals and the crystal structure of ingots. The pouring temperature of copper pipes is generally 1120~1180 ℃, and the pouring temperature of large-sized ingots is generally lower. The casting speed of the copper tube is low, and the metal level in the mold can be cast in an open flow manner without any protection; The melt needs to enter the mold through the hole at the bottom of the funnel. The design of funnel aperture should meet two conditions at the same time: one is to ensure the flow matching the casting speed; Second, so that the scum on the liquid level cannot flow into the crystallizer from the funnel hole; The copper tube ingot is easy to produce air holes and concentrated shrinkage cavities. At the end of pouring, the joint coating must be carefully carried out to avoid concentrated shrinkage cavities in the ingot. The red copper tube is a bar shaped object made of copper and zinc alloy, named after its yellow color. Copper content is 56%~68% brass, and its melting point is 934967 degrees. Brass has good mechanical properties and wear resistance, and can be used to manufacture precision instruments, ship parts, gun casings, etc. Different zinc content also has different colors. For example, when the zinc content is 18%, 20% will be red and yellow, while when the zinc content is 20%, 30% will be brown and yellow.

The large diameter coated medical copper tube can deform to prevent the risk of ductile damage; The medical copper tube has sufficient plastic deformation, and the medical copper tube is capable of deformation. It is stipulated that the plastic deformation and ductility of medical copper tubes are good. Good plastic deformation can ensure that the structure can have significant deformation before destruction. In some peak periods of the structure, the tectonic stress will be redistributed, which is the risk water of ductile destruction. For the structures with plastic deformation design scheme and the structures in disaster areas more kinetic energy should be digested and absorbed when the structure is destroyed the size of the deformation working capacity of medical copper tubes has a particularly critical practical significance. 3 Production and processing characteristics of medical copper tubes. It can be integrated with cold and heat treatment, and will not cause great harm to compressive strength, plastic deformation and ductility due to such production and processing. 4 Weldability of medical copper tube. The welding of medical copper tube is a rapid heating and cooling process. The metal materials in the welding and heat affected zone need to go through heating and melting, physical reflection cooling and crystallization, and solid state change in a very short time. The industry trend is a kind of medical copper tube. Because there is no seam in the middle, it has more advantages in strength. Medical copper tubes have many different s in practical application, and each different will make the medical copper tube work well.Advantages of medical copper tubes: compared with solid copper tubes such as round steel, medical copper tubes have the same tensile strength, torsional strength, and tensile strength, and their net weight is relatively light. One is plastic copper tubes cut for social and economic development, which are widely used in the production and processing of spare parts and mechanical parts, such as oil drilling equipment, rotating shafts, bicycle frames, and steel medical copper tube frames used in engineering construction. This kind of welded medical red copper pipe is developed under the special conditions that the temperature is all over and the composition is extremely unbalanced. After this kind of welding, it can produce detailed welding joints to maintain special performance indicators, which is the specified weldability. 5 Performance of medical copper tube. It refers to the service life of medical copper tube. The production and processing of annular parts with medical copper tubes can achieve the utilization rate of raw materials, simplify the production process, save raw materials and manufacturing hours, such as needle bearing throw rings, hydraulic jack sleeves, etc. At present, medical copper tubes have been widely used for production and processing. Disadvantages of medical copper tubes: medical copper tubes are also indispensable raw materials for various strategies. Drums must be produced and processed by medical copper tubes. Medical copper tubes can be divided into round medical copper tubes and profiled steel according to their different cross-sectional areas. Due to the large circle area under the same diameter specification, the annular pipe can be used to transport many large diameter medical copper pipes. Large diameter coated medical copper pipes are widely used in tap water, natural gas, petroleum, chemical industry, power, marine and other engineering fields. There is no solvent in the coating and no leakage, so it will not pollute the medium transported, thus ensuring the purity and hygiene of the fluid. The temperature range from - 40 ℃ to+80 ℃ can be used alternately in cold and hot cycles, without aging and cracking, so it can be used in cold areas and other harsh conditions. When processing medical copper tubes, the medical copper tube factory will use pickling, which is an indispensable part of most medical copper tubes Pickling process is the treatment after removing surface oxide scale (Carbon steel - stainless steel - lime saponified phosphorus, butter, oil, copper and aluminum pipes - and the old ones, and then wire drawing processing. Then what are the points to be noted when washing? 1 When washing the medical copper pipes, they need to be carried out in the flowing clear water tank, so as to avoid secondary pollution. When washing, the medical copper pipes need to be fully immersed in water. At this time, the sling should be relaxed, and it can be lifted up and down three to four times. If the medical copper tube is not acid resistant, the surface may be oxide and oil, and the phosphating solution cannot remove nuclear energy. However, after acid washing of medical copper tubes, the water in the medical copper tube needs to be cleaned to avoid water corrosion and oxidation of the medical copper tube. Therefore, it is necessary to carry out solvent treatment as soon as possible. 4 When the medical copper tube is washed, the iron salt content must be controlled within a certain range, and it cannot exceed the standard, otherwise the medical copper tube may be damaged.


MannheimSquare aluminum tubeStrategies and solutions to maximize value



The utility model relates to a connecting structure, in particular to a connecting structure of a copper tube and an aluminum row. At present, most of the copper aluminum transition joints have not been effectively protected. In this way, under the condition of long-time electrification and heating and affected by the water vapor or corrosive gas in the air, the parts at the connection point are more likely to be oxidized, resulting in the reduction of the effective contact area of the connection point, the increase of the contact resistance, and the excessive heating or even burning of the connection point.

When stacking, it shall be stacked reasonably and placed first.

Xiao Bian would like to talk about the production of a copper tube for automotive air conditioners to help you better understand this product. During the production of automotive air conditioning copper tubes, bending deformation and torsion deformation are very easy to occur. Therefore, attention should be paid to the use of straighteners in production, and the tubes should be straightened to meet the requirements of automobiles for automotive air conditioning copper tubes. The air conditioner copper pipe straightener uses vertical and horizontal rubber rollers to straighten it, so that the air conditioner copper pipe can be used by users to a certain extent.Nowadays, most straighteners can only straighten some copper pipes for automobile air conditioners with low accuracy, while most straighteners with high accuracy can only straighten some copper pipes for automobile air conditioners with small defects. Therefore, the straightening equipment used for rectangular pipes with different bending degrees is different,MannheimRed copper tube, which brings a lot of inconvenience to the production of copper pipes for automobile air conditioners. Therefore, some other construction processes should be used, To solve some problems arising from the above production. For example, in the preliminary manufacturing of medical copper tubes for automobiles, the air conditioner copper tube materials can be selected according to the actual size required by the user, and then the air conditioner copper tubes for automobiles can be manufactured, followed by pickling, putting the produced air conditioner copper tube materials into the pickling tank for pickling, and then stretching and then stretching the pickled air conditioner copper tubes according to their size requirements. The warehouse shall not be mixed with acid Alkali, salt, cement and other materials that are corrosive to steel are stacked together. Air conditioning copper pipe is based on carbon structural steel. The phenomenon of torsional deformation of air conditioning copper pipe requires weeds and all sundries on the site. One or more alloy elements shall be added appropriately to improve the mechanical properties, toughness and hardenability of the annealing steel. The automobile air conditioner copper tube is also called the air conditioner copper tube. In fact it refers to a kind of air conditioner copper tube with equal side length. The automobile air conditioner copper tube is made of strip steel as raw material, and then processed and rolled by relevant processes. It is generally made into a circle after the strip rod is unpacked, straightened, curled and welded. Among them, hardness is an index to measure the degree of hardness and softness of automotive air conditioner copper tubes. At present, the commonly used hardness method for measuring product hardness in production refers to the use of an indenter with a certain geometric shape to measure the hardness value of the metal surface being tested under a certain load according to its degree of coverage. The air conditioner copper pipe in the automobile air conditioner copper pipe is also divided into weld and seamless. Seamless air conditioner copper pipe is a metal material formed by directly using seamless round pipe. The plasticity of the air conditioner copper pipe refers to the ability to deform under a certain load without its original performance. The copper pipe for automobile air conditioner is a hollow and square section. The light thin-walled copper pipe for air conditioner is also known as steel cold-formed profile. It is a square section steel made of strip or coiled plate after processing in the cold bending area and high-frequency welding. In addition to being used in the automobile industry, machinery manufacturing, steel construction and other projects, shipbuilding, solar power generation support, steel structure engineering, electric power engineering power plants, agricultural and chemical machinery, glass curtain walls, boiler construction, highway railings, housing construction, pressure vessels, oil tanks, bridges, power station equipment, lifting and transportation machinery and other high load welding structures. In addition to the thickening of the wall, the size and external straightness of the extra thick wall air conditioning copper tube can both exceed the water content of the resistance welded cold formed air conditioning copper tube. Therefore this kind of automobile air conditioning copper tube has better comprehensive mechanical properties and has the advantages of hot processing, cold processing, weldability and corrosion resistance.

Installation requirements.It is still necessary to pay attention to the materials used for pipes and the hardness of materials, so as to comprehensively consider and avoid problems. The polymer is thermally copolymerized with the polymer to form the big data of the molecules connected by the ion bond of the co thermal polymerization. The thermal copolymerization is carried out according to the DA reverse reaction. The disadvantage of such materials depends on the fact that if simple heat treatment process is improved without additional metal catalyst, chemical formula or other unusual surface treatment of metal materials will lead to ionic bond in the area to be repaired and can open the gap several times. Copper tube concrete based textile materials. Self repairing concrete is a basic concept that mimics the automatic basic metabolism of some chemicals of the injured part by biological tissues, so as to make the injured part heal. Hollow glass fiber or liquid core optical fiber may damage the hollow bag of concrete raw materials, damage the hollow glass fiber or liquid core optical fiber, and flow the adhesive to the damaged part, so that the gap medical copper tube can be healed again. Cause of surface damage of copper tube. Copper tube is also a kind of material commonly used in engineering. The surface shall also be protected from scratches. The surface of the copper tube is also easy to be damaged, road bridges and undersea bridges often appear. Most road bridges are built with plastic coated copper pipes. With plastic coated copper pipes in large cities, engineering construction in large cities will become stronger and stronger. The actual operator shall carry out the actual operation of the heating furnace, yze the materials of the heating furnace, and select the type and concentration of cleaning solution. Pay attention to the cleaning time and temperature to develop more effective solutions, and also develop some safety protection measures. An obvious feature of plastic coated copper pipe is heat resistance because this kind of seamless steel pipe for heating furnace is mainly used for machining parts. Because the seamless steel pipe must be heated at high temperature during production and processing. What are the plastic coated copper tubes to prevent wear. What are the plastic coated copper tubes to prevent wear. We all know that all objects will wear in application, so how to prevent the wear of oil cracked pipes. Now let's introduce it to you. The packaging of petroleum cracking tubes shall be able to prevent and damage during normal loading, it shall be indicated in the contract; If it is not marked, the supplier shall select packaging materials and packaging. Packaging materials shall comply with relevant requirements. If the material is not packaged, it should be suitable for the intended use and avoid obvious and natural purification. If the customer stipulates that the surface layer of the cracked tubing should not be damaged by bumps, it can be considered to repair and install the cracked tubing in the middle. Rubber sleeves, tree trunks, straw ropes, fiber cloth plastics, pipe caps, etc. can be used for maintenance and installation. The thick wall petroleum cracking pipe can choose the internal fulcrum or external structure. Because thick walled tubes are thin. The supporting frame and frame are made of steel, which is inconsistent with the plastic coated copper pipe. If the customer needs a packer, the petroleum cracking tube can be weighed in a decentralized way. However, the specification must be 159MM500MM.

In addition, brass has a unique sound, so the gongs, cymbals, bells, horns and other instruments in the East, as well as the western brass instruments, are all made of brass, which is a kind of non-ferrous metal processing bar with good processing performance and high conductivity. It is mainly divided into copper tube (copper zinc alloy, cheaper). The manufacturing principle of copper tube: All elements without exception reduce the conductivity and thermal conductivity of the copper bar. All elements are dissolved in the copper bar, causing lattice distortion of the copper bar, causing wave dispersion when free electrons flow in a directional direction, increasing the resistivity. On the contrary, there are no or few elements with solid solution in the copper bar, which has little impact on the conductivity and thermal conductivity of the copper bar, Special attention should be paid to the fact that the solid solubility of some elements in the copper bar decreases sharply with the decrease of temperature. The precipitation of simple substances and metal compounds can not only strengthen the copper bar alloy by solid solution and dispersion, but also reduce the conductivity slightly. This is an important alloying principle for the study of high-strength and high conductivity alloys. Here, it should be pointed out that the alloy composed of iron, silicon, chromium and copper bar is a very important high-strength and high conductivity alloy; As the influence of alloy elements on the properties of copper bars is superposition, CoCrZr series alloys are * high-strength and high conductivity alloys; It is not easy to heat. Semi continuous casting copper tube has excellent conductivity. Copper tube has excellent conductivity. Alloy copper to ensure safety and fatigue resistance. Tin phosphor bronze jack adopts hard wire electrical structure without rivet joint or conflict contact, which can ensure excellent touch, good elasticity and smooth dial. Phosphor bronze has high corrosion resistance, wear resistance, and will not produce sparks when stamping. It is used for medium speed and heavy load bearings. The working temperature is up to 250 ° C, and the active centering is insensitive to deflection. The bearing force is uniform, and the bearing capacity is high. It can withstand radial load and self lubrication without protection. The company is a manufacturer specializing in the production of various bronze tubes, bronze rods bronze plates and profiled bronze profiles. Technical advantages: The maximum diameter of bronze bars and pipes can reach 300mm, while that of plates can reach 600mm. The wall thickness of bronze tube can be as small as 4mm. The copper tube is a common bronze material. The aluminum content of copper tube generally does not exceed 5%. Sometimes, an appropriate amount of iron, nickel, the aluminum content is 5%, and the 7% copper tube has good plasticity and is suitable for cold working.


MannheimSquare aluminum tubeStrategies and solutions to maximize value



Copper tube can be strengthened by heat treatment, its strength is higher than that of copper tube, and its high temperature oxidation resistance is also better. When the aluminum content is greater than 7% and 8%, the strength increases, but the plasticity drops sharply. Therefore, seawater, seawater carbonic acid and most organic acids are higher than those of copper tube. Copper tubes can be made.

Total quality assurance.When I need to use more quantity, what are the factors that cause the surface corrosion of copper tubes. Introduce the factors that cause the surface corrosion of copper tubes. Surface pollution: The oil, dust, acid, alkali, salt, etc. attached to the surface of the workpiece will be converted into corrosion medium under certain conditions, which will react with some components in the stainless steel parts to produce chemical corrosion and rust.

It contains less impurities to reduce conductivity and thermal conductivity. The trace oxygen has little effect on conductivity, thermal conductivity and processing properties, try to protect the surface of the copper tube.

Mannheim.Air conditioning copper pipe is a common metal material in daily work of industrial production. The conductivity, heat conduction and corrosion resistance are excellent, and the W shape trend of air conditioning copper pipe is depressed due to the high copper content. Good machinability, fusion welding and brazing are very good. The cutting of air conditioner copper pipe is a very energy consuming work. The following items need to be paid attention to in order to cut neat and beautiful parts. Before cutting the air conditioner copper pipe, the cutting machine should carry out calibration and other operations. You can try to use scrap metal first to prevent machine problems from causing me to cut off defective products.

The operation is very convenient. The forward and reverse switches are set on the front panel and can be toggled up and down. The advantage is power saving (efficiency 90%,Mannheim15CRMO alloy plate, time saving (only two thirds of the time of the original rectifier, or even shorter), material saving (at the same time, raw materials can be saved 30%, and efficiency is high (more than one third of the output value of each savings). The degreased copper tube has less deformation resistance and is easier to form. The original color of copper should be orange or rose, but it is easy to oxidize into purple in the air, so it is also called degreasing copper tube. In terms of conductivity and thermal conductivity, brass rod has no hardness of copper rod, and degreased copper tube is inferior to copper wire. The defatted copper tube Huangtong brand has its own advantages and disadvantages, but the differences are also luminous points. Can affect people's lives, because it can be applied to different aspects. As the conductivity of copper is better than aluminum, copper bus is widely used in electrical equipment, especially in complete power distribution equipment. The UVW phase bus and PE bus in the general distribution cabinet are copper bus; In use, copper bus bars are generally marked with colored letters or painted with colored paint.

In addition, brass has a unique sound, so the gongs, cymbals, bells, horns and other instruments in the East, as well as the western brass instruments, are all made of brass, which is a kind of non-ferrous metal processing bar, with good processing performance and high conductivity. It is mainly divided into copper tube (copper zinc alloy, cheaper). The manufacturing principle of copper tube: All elements without exception reduce the conductivity and thermal conductivity of the copper bar. All elements are dissolved in the copper bar, causing lattice distortion of the copper bar, causing wave dispersion when free electrons flow in a directional direction, increasing the resistivity. On the contrary, there are no or few elements with solid solution in the copper bar, which has little impact on the conductivity and thermal conductivity of the copper bar, Special attention should be paid to the fact that the solid solubility of some elements in the copper bar decreases sharply with the decrease of temperature. The precipitation of simple substances and metal compounds can not only strengthen the copper bar alloy by solid solution and dispersion, but also reduce the conductivity slightly. This is an important alloying principle for the study of high-strength and high conductivity alloys. Here it should be pointed out that the alloy composed of iron, silicon, chromium and copper bar is a very important high-strength and high conductivity alloy; As the influence of alloy elements on the properties of copper bars is superposition, CoCrZr series alloys are * high-strength and high conductivity alloys; It is not easy to heat. Semi continuous casting copper tube has excellent conductivity. Copper tube has excellent conductivity. Alloy copper to ensure safety and fatigue resistance. Tin phosphor bronze jack adopts hard wire electrical structure without rivet joint or conflict contact, which can ensure excellent touch, wear resistance, and will not produce sparks when stamping. It is used for medium speed and heavy load bearings. The working temperature is up to 250 ° C, and the active centering is insensitive to deflection. The bearing force is uniform, bronze rods, bronze plates and profiled bronze profiles. Technical advantages: The maximum diameter of bronze bars and pipes can reach 300mm, while that of plates can reach 600mm. The wall thickness of bronze tube can be as small as 4mm. The copper tube is a common bronze material. The aluminum content of copper tube generally does not exceed 5%. Sometimes, an appropriate amount of iron nickel, manganese and other elements are added to further improve the performance. It has high strength and good wear resistance. It is used for copper sleeves and wear resistant parts with high strength. The outstanding feature of t2 copper tube is its good wear resistance. The difference between copper tube and copper tube The copper tube is a copper based alloy with aluminum as the main alloy element. The copper tube is a copper based alloy with tin as the main alloy element. The mechanical properties of copper tube are higher than that of copper tube. The aluminum content of the copper tube in practical application is between 5% and 12%, the aluminum content is 5%, and the 7% copper tube has good plasticity and is suitable for cold working.