How to distinguish true and false aluminum alloy g

2022-07-22
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Outside the building wall, the glass frame is suspended on the aluminum alloy structural frame. The wall composed of aluminum alloy and glass is called aluminum alloy glass curtain wall

I. what is aluminum alloy glass curtain wall?

outside the building wall, the glass frame is suspended on the aluminum alloy structural frame. This wall composed of aluminum alloy and glass is called aluminum alloy glass curtain wall. The self weight and wind load of the curtain wall are transmitted to the aluminum alloy frame. Because the design type and division of the curtain wall are different, various facade effects can be obtained

aluminum alloy fixed window is an aluminum alloy glass body composed of aluminum and glass in the middle of the building wall, which is called aluminum alloy fixed window. It has no similarities with aluminum alloy glass curtain wall in material, structure, manufacturing and installation. Curtain wall uses more materials than fixed window, and its design and manufacture are complex, and the cost is more than twice as high. Some manufacturers call the fixed window "simple aluminum alloy glass curtain wall", which is pure deception. Many users are looking for cheap fixed windows instead of curtain walls

II. Classification of aluminum alloy glass curtain walls

aluminum alloy glass curtain walls generally represent aluminum alloy curtain walls with frames. There are aluminum alloy frames around the glass, that is, the glass is embedded in the aluminum alloy frame. The self weight and wind load of the glass are borne by the aluminum frame embedded in the glass and then transmitted to the aluminum alloy frame. The aluminum alloy glass curtain wall has no glass inlaid aluminum alloy frame, but is adhered to the aluminum alloy frame with structural adhesive. The self weight and wind load of the glass are transferred to the aluminum alloy frame by the glue. Hidden frame curtain wall is divided into full hidden and semi hidden, and semi hidden is divided into vertical hidden horizontal hidden and horizontal hidden vertical hidden

III. characteristics of aluminum alloy glass curtain wall

1. Material selection: according to the height of aluminum alloy glass curtain wall, division size, local maximum wind load in different regions, seismic coefficient, maximum temperature difference in winter and summer sunshine and other factors, design and calculate how much aluminum alloy curtain wall profile section is required to meet the design load needs

2. Curtain wall production: according to the curtain wall profile selected by calculation, according to the design division size, the frame is made and fixed outside the wall. When making the frame, we must consider the thermal expansion and cold contraction of aluminum. According to the height and width of the curtain wall, how much contraction joint should be considered. The length change of aluminum is generally expressed by △ I = ATI △ T, △ I length change, at expansion coefficient, I aluminum length, △ t temperature difference. According to the formula, the longer the aluminum, the greater the temperature difference between winter and summer, the greater the change of aluminum length. In order to ensure the firmness of the aluminum alloy glass curtain wall frame, a simple profile (as shown in Figure 1) is added in the middle of the aluminum profile of the curtain wall to ensure that the expansion joint changes freely due to temperature changes, so as to ensure the integrity of the frame

3. Installation of curtain wall glass

one installation method is to install by components. First, install the vertical components on the frame and set the line, then connect the two horizontal components with the installed vertical components on both sides to form a frame, and finally insert the glass. This kind of installation, convenient transportation, can only be installed outside the wall, requiring scaffolding or special workbench. In addition, the installation method is to first process individual glass inlaid frames according to the division size, and then hang them one by one on the aluminum alloy frame outside the wall, both inside and outside

no matter which method is used for installation, it must ensure that the air tightness, water tightness, wind pressure resistance and seismic resistance of the curtain wall must meet the national standards, and the above performance must be based on the test data

IV. aluminum alloy fixed windows are not curtain walls, let alone simple curtain walls

aluminum alloy fixed windows are by no means curtain walls, which are completely different in the use of materials, production and installation of glass, let alone the requirements of three properties. Aluminum alloy square tubes or flat tubes for fixed windows instead of curtain wall profiles. Fixed windows are generally installed in the middle of the building wall, and some fixed windows are also made outside the wall in order to deceive users. The grid frame is composed of aluminum alloy square tubes and flat tubes, and the glass is fixed in the middle of the grid frame with aluminum alloy battens or wood screws. Generally, the normal wall thickness of aluminum alloy square tubes is 1.3-1.4 mm. Some aluminum alloy square tubes have a wall thickness of less than 1 mm. Such a thin wall thickness can bite oneortwo buckles of wood screws. How much force can wood screws bear? If the glass grid is large, can the glass be firmly fixed on the aluminum? The glass of the curtain wall is inlaid into the special groove of aluminum, and the fixed window is pressed on one side or one point of the glass with battens or wood screws, which can't stand the wind and rain. This kind of large-area aluminum alloy fixed window gives people the feeling of glass curtain wall. It is easiest to deceive inexperienced users. We found that the designers of some design institutes have also been deceived into simple curtain walls, and what is more ridiculous is to indicate simple aluminum alloy glass curtain walls on drawings. This kind of fixed window has great hidden dangers. First, there is no complete design and calculation, and the connection firmness of the grid frame is very poor. The connection between steel and aluminum profiles produces electrochemical corrosion and aluminum is damaged. Second, the thermal expansion and cold contraction of aluminum are not considered at all, let alone the expansion joint. In some cities, the temperature difference between winter and summer is about 100 ℃, and the elongation and shortening of aluminum materials are very obvious. Therefore, the so-called simple curtain wall installed in summer is often encountered, and the glass breaks in a large area in winter. More seriously, the whole large fixed window will tilt, bulge and break. Generally, the price of fixed windows per square meter is about half lower than that of aluminum alloy glass curtain wall. Please don't try to be fooled by cheapness

v. aluminum alloy hidden frame glass curtain wall

aluminum alloy hidden frame glass curtain wall is the latest aluminum alloy glass curtain wall in the world, and it is also a controversial new technology in the world. It is now banned in Germany and Japan. There is no aluminum alloy frame on the surface of the curtain wall, and the single reflection coated glass is used to form a large glass mirror type curtain wall, which has a strong sense of perception, and the wall can reflect the cars and horses on the road. The interior cannot be seen from the outside of the glass, but the exterior can be seen from the interior. It is precisely because of this charm that China has formed a craze for hidden frame curtain walls. The design, production and technical requirements for materials of this kind of curtain wall are particularly strict, with great difficulty, technical complexity and risk

the aluminum alloy hidden frame glass curtain wall has no aluminum alloy outer frame to hold the glass and bear the load. It completely relies on structural glue to stick hundreds of pieces of glass to the aluminum profile frame, and the gap between the glasses is bonded with sealed structural glue

1. Requirements for profiles of aluminum alloy hidden frame glass curtain wall:

the design and calculation of aluminum alloy hidden frame glass curtain wall is very important. The strength requirements should be calculated according to the astronomical data of various regions, the height of the curtain wall and the size of the grid, and the appropriate special profiles for aluminum alloy hidden frame curtain wall should be selected. The section size of the profile is determined by the calculated strength. Alloy grade LD31 (foreign known as 6063) T5 state, mechanical strength should meet national standards. The thickness of profile oxide film of adhesive for concealed frame curtain wall shall be greater than 15 μ The oxide film should be firm and high. After anodizing, the aluminum is electrophoretic painted, which is called electrophoretic painting on the surface of aluminum profile. The purpose of painting is to enhance the acid and alkalinity resistance of the aluminum surface and increase the surface gloss of oxidation. However, for the hidden frame curtain wall, the above effect is not obvious because the aluminum is stuck inside. More importantly, there is no reliable data to explain the firmness between the paint layer and the oxide film, Because the self weight and wind load of the glass are transmitted to the structural adhesive by the glass through the paint film. If the paint film is not firm and is stuck off, the glass will fall down, causing serious consequences. Therefore, the use of electrophoretic painted aluminum in the hidden frame glass curtain wall should be particularly careful, and it is better to reuse it with basis

another method of aluminum profile surface treatment is electrostatic spraying, which can be sprayed with powder or liquid spray paint. Its purpose is to improve the monotonous white and bronze color of anodic oxidation. It can be sprayed with dozens of different colors, with good acid and alkaline resistance. The powder spray paint is polyurethane and resin, with good impact resistance, friction resistance, and fading on the long-term exposed surface of the sun. The liquid spraying coating is fluorinated carbon spraying. This kind of spraying profile is suitable for high-rise buildings. It is not afraid of long-term ultraviolet radiation and does not produce cracks. Fluorinated carbon electrostatic spraying is widely used abroad, mostly for aluminum curtain wall. Glue is applied on the sprayed surface, which is used for hidden frame curtain wall. How about the firmness of the sprayed film? Now I don't see the data, so it's better to be cautious

2. Coated glass

there are several methods of glass coating, which have been introduced in the 21st issue of the conference, among which hot coating is the best. The film has been coated in the production process of float glass, and the film is inside the glass. This coated glass can be thermally bent into various arcs, which can not be produced in China, but produced in the United States and Belgium. Most of the films introduced by the state are vacuum sputtering coatings, which are coated on the surface of glass. When this coating is applied to the concealed frame glass curtain wall, the film faces the inside, and the structural glue should be adhered to the coating. If the coating is not firm, the coating will be stuck off, and the glass will fall off. Therefore, the coated glass must be strictly required. The association proposed that the coated glass factory should issue a guarantee that it will not be stuck for at least ten years. At the same time, the advanced level of equipment and the data of various tests, especially grinding tests, should be investigated. We also need to know the source of float glass used for coated glass, whether it is the original piece produced by our factory, produced with nearby manufacturers, or the original piece bought from afar. The firmness of the coated glass film is closely related to the freshness of the original piece. For example, if the original piece of float glass is produced within seven days, the coating effect of the same coating equipment is the best, and the firmness of the coating decreases significantly after seven days. The original glass is not fresh. Even if a ten-year guarantee is issued, we should also consider whether the guarantee is reliable. When buying coated glass, especially the coated glass used for hidden frame glass curtain wall, you should understand the above situation

3. Silicone structural adhesive

silicone structural adhesive commonly used in the world are: General Electric Company of the United States, abbreviated as GE company, taokangling company of the United States, Ronald company of France, and wacker of Germany. China is still unable to produce structural adhesive. Silicone structural adhesive can be divided into two components and one component. Two component structural adhesive is used in large quantities. Two component structural adhesive needs a glue applicator, but the glue applicator is expensive, about 30000 US dollars per unit. Generally, one component structural adhesive can be used, and a simple manual glue applicator can be used. GE's single component adhesive has a storage period of one year for ge4000, six months for Tao Kangling for dc795, and six months for Ronald cec70a in France, which means it must be used up within the storage period and expired

VI. various types of false hidden frame glass curtain walls

many hidden frame glass curtain walls can be seen everywhere in China. Especially in some downtown areas of cities, there are reflective glass curtain walls of different sizes above the shop facade, namely hidden frame glass curtain walls. Many store managers can't call the curtain wall by its name, and they have to do it even if others do it well. Some decoration companies used to only do interior and exterior decoration, and they don't understand the hidden frame curtain wall. If they don't understand it, they don't ask or learn, but take it for granted. Here are the following situations

1. replace aluminum with steel; Replace structural glue with ordinary sealant and fake hidden frame curtain wall, such as the hidden frame curtain wall of fengshengyuan restaurant made by Beijing Daxing decoration company. Steel should rust. 333 is a general sealant, not a structural adhesive, which can't stick at all. In this way, the manager of Daxing County decoration company said he dared to guarantee five years

2. steel is used as the grid frame, coated glass is generally glued to foam board and plywood, and then foam board and plywood are fixed on the angle steel welded into the grid frame. For example, in the Sales Department of Kunqu hardware and electrical company in Baotou, Inner Mongolia, the glass was completely broken within two months of completion

3. use aluminum alloy square tubes instead of curtain wall profiles to make grid frames, and use general glue to stick the coated glass, which cannot be stuck in the two glasses

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