1. How to choose aluminum profiles
my country’s architectural aluminum products started in the early 1980s, and the development speed is the fastest in the world. It has only been a little more than ten years from aluminum profiles, aluminum doors and windows, aluminum curtain walls to hidden frame glass curtain walls. The main reason for the rapid development of my country’s architectural aluminum products is: the introduction of aluminum and aluminum door and window production lines from more than a dozen foreign countries, learning from the strengths of various countries, and insisting on digestion and absorption is one of the important reasons.
Due to the rapid development, many problems have also arisen: for example, the number of architectural aluminum manufacturers in the country has increased rapidly, and the production volume is too large. The production volume of most aluminum factories cannot meet the design indicators. Now it is very good for manufacturers to achieve half of the design capacity. The competition for aluminum sales is very fierce. There are more than 4,000 aluminum door and window manufacturers (excluding self-employed households). Although. The construction industry has developed rapidly in the past two years, the demand for aluminum doors and windows is far less than the supply of aluminum. Therefore, in the aluminum industry, production exceeds sales, and the production capacity of aluminum doors and windows is very large. Although the demand for aluminum doors and windows has increased rapidly, the aluminum door and window industry is still “more porridge than monks”. In order to get the task and the contract, some aluminum door and window factories use all means to deceive users to deliberately lower the project quotation. After getting the contract, they replace the good with the bad and the real with the fake, still to achieve the purpose of making money. Don’t just go for cheapness and ignore the quality and be deceived. Here is a brief introduction on how to distinguish the advantages and disadvantages of aluminum and aluminum doors and windows for users’ reference.
2. How to choose aluminum profiles There are many aluminum factories in China
Due to different conditions, the aluminum materials produced vary greatly, and the sales prices also vary greatly, with a difference of 4,000 to 5,000 yuan per ton. The domestic price of aluminum ingots is basically the same. In the processing process, there is such a large price difference, and the quality difference is definitely large. The quality of aluminum profiles is determined by the following factors:
(1) Alloy elements: 6063 alloy is an alloy with aluminum, magnesium and silicon as the main elements. Each element has a certain range of content. Magnesium is expensive. In order to reduce costs, some manufacturers reduce the amount of magnesium to the minimum allowable content. Some even go so far as to reduce the magnesium content to below the minimum allowable content. Some factories also add waste wires, waste pots and waste aluminum pots to the alloy, which basically does not qualify as 6063 alloy. This results in very low mechanical strength of aluminum profiles, which can be easily bent with two hands, commonly known as “noodles”. This is one of the reasons why aluminum can be thousands of yuan cheaper.
Regular aluminum manufacturers have internal standards when formulating alloy components. That is, within the range of various element contents, each factory has its own smaller variation range. The ratio requirements between aluminum, magnesium and silicon are very strict. Each factory has its own data and keeps it confidential. Only alloys made with qualified formulas can guarantee quality. Otherwise, no matter how they are processed in the future, the quality will not be improved.
(2) Aluminum alloy melting furnace How to melt 6063 alloy and what kind of furnace to use are also very important. The furnaces currently used in China are at the level of the 1940s and the 1990s. The worst manufacturers use primitive crucible boilers. There are coal-fired, oil-fired, gas-fired and electrically heated melting furnaces. Some furnaces have chimneys, while others do not. Square furnaces (rectangular furnaces) are generally used, while advanced ones are round furnaces. Some round furnaces can tilt to pour molten aluminum. In terms of tonnage, there are one-ton, two-ton, five-ton, ten-ton, twenty-five-ton and fifty-ton aluminum melting furnaces. The more advanced ones add a static furnace under the aluminum melting furnace. The static furnace is important for preparing 6063 alloy. Slag and gas can be removed in this furnace, and then aluminum bars can be cast for extrusion. The quality of alloys prepared in the primitive coal-fired furnace and the modern round furnace is absolutely different. Generally, furnaces should have chimneys regardless of the fuel used. Most of the waste gas and waste slag generated during the combustion of the fuel can be discharged from the chimneys. If there is no chimney, all the waste gas and waste slag will melt in the molten aluminum. In this way, the aluminum bars cast for extrusion will have serious slag inclusions and bubbles inside. This is one of the reasons for the poor quality of aluminum materials and one of the reasons for the low price of aluminum.
(3) Alloy casting The level of domestic casting equipment is also very different. The oldest domestic casting equipment is iron mold casting at the level of the 1940s, and the most advanced one is hydraulic semi-continuous casting. The crystal structure of the iron mold casting bars is very poor, and there are a lot of slag inclusions and bubbles in the casting bars. The quality of the casting bars is very poor. The most common ones used in general factories now are horizontal casting (also known as continuous casting) and semi-continuous casting. Most of the semi-continuous casting is wire rope driven, and the best is hydraulic transmission. The length of the semi-continuous casting bars varies, generally 3 meters, 4 meters, and even 8 meters. Semi-continuous casting is a pit type, which is cast while descending, and is cooled on all sides by cold water. Because the water cooling is uniform on all sides, the crystal structure of the casting bars is uniform and fine. However, the downward transmission of the steel wire rope is not as stable as that of the hydraulic transmission. The surface of the hydraulically cast rod is smoother than that of other cast rods. The smooth surface of the cast rod is one of the prerequisites for extruding good profiles.
The surface of the cast rod cast by other methods is relatively rough. In order to ensure the quality of the profile, the cast rod is sometimes cut first to remove the rough surface of the cast rod. The semi-continuous casting mold commonly used now is an advanced, hot top same-level casting mold. The characteristics of this casting mold are that it can cast several to dozens of rods at a time, and the casting quality is good. Only with high-quality 6063 aluminum alloy cast rods can it be possible to produce good aluminum profiles. If the original and outdated casting equipment is used, it is impossible to cast good cast rods, and it is impossible to produce good aluminum profiles. There are many aluminum plants in China that do not have equipment for producing aluminum rods, but purchase 6063 alloy rods from electric aluminum plants or other plants. In such aluminum plants, the quality of aluminum is controlled by the cast rod production plant, and it is difficult to achieve stable quality of the aluminum produced.
Profile extrusion my country has a wide variety of profile extruders, with a wide range of grades, which is also the best in the world. There are simple extruders made by the factory, some modified from extrusion plastic machines, some made in China, and most of them are made abroad. Many people also think that foreign extruders are better. Good and bad extruders are part of it. The same cast rods have different quality profiles. We often see 6063T5 used in building aluminum doors and windows. For example, the blade of a steel knife must be quenched in water to be hard and sharp, and the quenching of aluminum can be water-cooled or air-cooled.
The 6063 profiles used in construction are quenched by air cooling. The quenched aluminum is placed in an aging furnace for a certain period of time. The internal crystals of the aluminum are rearranged and the mechanical strength is significantly improved. Among all metal alloys, only aluminum alloy has an aging state.
