I. Development Status of Aluminum Cans in China
In recent years, the annual demand for the can market in China has reached 6 billion to 7 billion. With other metal material cans and plastic packaging containers can not be compared advantages, namely, light weight, long shelf life, strong anti-counterfeiting, easy to carry, recyclable and so on. Since the 1980s, its consumption has been increasing. With the improvement of the living standards of our people, the consumption of cans has continued to increase at a rate of more than 20% in recent years. Beer and carbonated beverages have been the major users of cans. According to the Packaging Association’s introduction, China’s beer production ranks second in the world, and its current annual output is more than 18 million tons, of which the production of cans with cans exceeds 5%, and the number of cans used is between 1.5 billion and 2 billion.
After 20 years of rapid development, China's aluminum processing industry has achieved remarkable achievements. The output of rolled aluminum and rolled steel has rapidly increased. In 2004, the output of rolled aluminum reached 1.5 million tons. However, in some high-precision aluminum strip products, products such as aluminum cans, high-grade PS substrates, disk substrates, auto body aluminum panels, and mirror aluminum ribbons are not yet capable of large-scale industrial production, resulting in related industries in the procurement of raw materials. Can only rely on imports. Due to the strict requirements on materials and internal organization of aluminum strips for cans, and the current level of technology and equipment in our country can not be met, except for a small part of domestic self-sufficiency, the vast majority of * imports to meet. From 1991 to 1996, a total of 348,800 tons of aluminum strips were used for cans, which reached 120,000 tons in 1996. From 1998 to 2004, the import volume and net imports of high-precision aluminum sheet and strip in China are still on an upward trend, and a considerable part of them are aluminum strips for cans, with an annual import volume of more than 100,000 tons.
At present, only the Southwest Aluminum Co., Ltd. can produce aluminium cans for aluminum cans (formerly Dongbei Light Alloy Co., Ltd. had produced them before), and other large manufacturers have not stepped in. Southwest China has also gone through hardships to master the process and production technology of aluminum strips for cans. The company took a lot of detours in the development process of the aluminum strip process for cans, and the loss was also very high. Before and after 1996, due to the fact that the technology did not pass, more than 3,000 tons of finished products were returned and warehouse materials could not be shipped. A backlog of more than 3,000 tons, and then all returned to production. Although SWA eventually developed aluminum strips for 3004H19 cans, it also paid tens of millions of dollars and a five-year price. Around 2000, this product produced about 10,000 tons. In September 2004, SWA successfully developed a 0.28mm, 0.285mm aluminum strip for cans, which is the thinnest in its kind in the country and has been welcomed by the market, filling the domestic gap. In the first half of 2005, the output of aluminum strips for the Southwest Aluminum cans increased by 432.61% over the same period last year. However, compared with foreign advanced aluminum materials, there is still a certain gap in the deep drawability (elongation rate, ear rate, etc.), and the intrinsic metallurgy quality still needs to be improved. In June 2005, the successful production of "1+4" hot strip rolling will be completed. Further improve the production and quality of aluminum strips for cans.
At present, China has a small quantity of tinplate cans with aluminum can lids. There are only a few products such as rice porridge, walnuts and peanuts. It is estimated that in the future, it will increase at a rate of 5% each year. According to the forecast of China Beverage Association, the output of carbonated soft drinks will reach 8 million tons by 2010. If the canning rate is calculated at 20%, the amount of cans will reach 12.4 billion.
Second, the world aluminum cans market progress
The current annual global demand is about 210 billion, accounting for more than half of the global metal container production. The proportion of aluminum cans consumed in major regions of the world is 53% in North America, 19% in Europe (including Australia, New Zealand), 14% in South America, and 14% in Asia.
The North American market is dominated by the United States. It is the birthplace of aluminum cans and is also the largest producer and consumer of aluminum cans worldwide. After entering the 1990s, the supply and demand market for North American cans continued to expand. By the end of the 1990s, supply and demand had stabilized and the growth rate was slow. In 2001, the amount of aluminum cans for beer and soft drinks in the United States was nearly 100 billion, including 64 billion soft drink cans and 33 billion beer cans. At present, there are 169 cans production lines in North America. The average production line speed is 1,522 cans/minute, and the total annual production capacity is about 109 billion. The market demand is about 107 billion. In the United States, aluminum can be used as the material for cans. About 40% of aluminum plates are used in the production of cans.
The supply and demand in the European market is booming. Since the mid-1980s, the European aluminum can market has been showing a steady growth trend, with an annual growth rate of 5%. In the production of beverage cans in Europe, tin cans and aluminum cans account for about half of the total, and about 14% of European aluminum metal materials are used for beverage production. However, due to the high value of recycling and reuse of aluminum metal, proceed from environmental protection. Now that there has been a lot of turning to aluminum, in 1999 63% of aluminum cans were made of aluminum, 2% more than in 1998, and 9% more in 1999 than in 1999. Tanks in Finland, Switzerland, Greece, Italy, and Poland tend to use 100% aluminum, 72% in the UK, 10% in Germany, and France, Belgium, Luxembourg, and the Netherlands account for 30% each. At present, the market demand for aluminum cans is about 40 billion.
From a global perspective, the global aluminum can market is mainly distributed in developed countries and regions, of which the United States is the most important consumer and production base. Aluminum strip cans and aluminum cans are relatively mature in production. Aluminum cans are used in cans. The annual demand is about 4 million tons, and it will increase steadily with the continuous improvement of people's consumption level and the enhancement of environmental awareness.
Aluminum strips for cans are a large market. The annual consumption accounts for 1/4 of the global aluminum rolled material consumption. Therefore, the aluminum strips used in cans abroad have become very common, and the production and technical processes are also relatively mature. The world's leading aluminum companies such as Alcoa, Caesar Aluminium and Chemicals of the United States, Hydro Aluminium, Aluminum Canada, Cocamco Australia, Japan Light Metals, etc., can produce high quality aluminum alloy cans Strips, now all have achieved international production and operations, and have occupied China's aluminum cans with aluminum strip market. For example, the Alcoa Tennessee Plant mainly produces aluminum cans for aluminum cans, hot rolling SMS five-stand hot rolling, the annual output of about 450,000 tons.
Third, aluminum cans processing technology
Aluminum cans occupy a considerable proportion in beverage packaging containers. The manufacture of cans combines the advanced technologies of many industries such as metallurgy, chemical industry, machinery, electronics, and food, becoming a microcosm of aluminum deep processing. With the ever-increasing competition in the beverage packaging market, for many can-making companies, how to minimize sheet thickness, reduce the quality of single cans, increase material utilization, and reduce production costs in the production of cans is an important part of the company’s pursuit. aims.
The main manufacturing process of the tank is as follows: coil conveying → coil lubrication → blanking, stretching → tank forming → trimming → cleaning/drying → stacking/unloading → undercoating → drying → color printing → bottom Tu → Drying → Inner Spray → Inner Drying → Tank Lubrication → Constriction → Spiral Compression Neck. In the process flow, blanking, drawing, can forming, trimming, shrinking, and screwing/flanging processes require mold processing. Among them, blanking, drawing and forming processes and molds are the most important. The level of technology and the level of mold design and manufacturing directly affect the quality and production costs of cans.
During drawing, the material at the edge of the blank forms a cup in the radial direction, so that the unit body in the plastic flow region is in a three-direction stress state with biaxial compression and uniaxial tension. Due to the effect of the arc of the punch and the arc of the drawing die, the thickness of the lower part of the cup is reduced by about 10%, while the thickness of the cup is increased by about 25%. In the forming process, there are many factors affecting the tensile stress of the metal. The value of the die angle of the die directly relates to the flow characteristics of the metal in the deformed zone, and thus affects the size of the forming force required for the stretching. Therefore, its value Reasonable or not has an important influence on the implementation of the process.
The stretching process of the can body is actually the stretching process of the tubular member. During the stretching process, the flange portion of the material is liable to destabilize under the action of compressive stress, resulting in wrinkling. Therefore, it is necessary to consider setting a blank to prevent wrinkling. Device. When the material passes through the die, the corner of the die is a transition zone. The deformation of the die is complex. In addition to the radial and tangential compression, it is also subject to bending, so the choice of die radius is particularly important. After the material passes through the corner of the die, it is in tension. Because the tensile force comes from the punch pressure, it passes through the corner of the punch. The material at the corner of the punch becomes the most severe and becomes the most vulnerable Dangerous section.
In the production of aluminum cans, one of the important aspects of reducing costs is to reduce the thickness, that is, to require thinner aluminum strips for cans. For decades, the manufacturing technology of aluminum cans has been continuously improved, and the weight of aluminum cans has been greatly reduced. In the early 1960s, every 1000 aluminum cans (including can bodies and can lids) weighed 55 pounds (about 25 kilograms). It was reduced to 33 pounds (15 kilograms) in the late 1990s and has now been reduced to less than 30 pounds, which is a reduction of nearly half from 40 years ago. During the 20 years between 1975 and 1995, the number of aluminum cans (capacity of 12 ounces) made from 1 pound of aluminum increased by 35%. According to Alcoa's statistics, the aluminum required per 1,000 aluminum cans was reduced from 25.8 pounds in 1988 to 22.3 pounds in 2000. Since the 1980s, the thickness of aluminum strips for the United States cans has decreased significantly, from 0.343mm to about 0.259mm. The lightweight progress of aluminum can lids is also evident. The thickness of the can lid aluminum fell from the initial 0.39 mm to 0.24 mm. Alcoa Inc., which is leading in the production of aluminium strips for cans, allegedly aimed thin-walled to about 0.18mm. This development trend is equally important for aluminum cans manufacturers in China, that is, we must increase research and development efforts, adjust the direction of technological research, in order to keep pace with the development of the global industry, and continuously enhance our competitiveness.
Due to the complex process of aluminum cans and the demand for raw materials, three-quarters of domestic cans are imported, and the raw materials used in domestic cans are all relied on imports. Both of them consume more than US$1 billion in foreign exchange annually, becoming an importer of cars and color TVs. The fourth largest consumer of foreign exchange after the refrigerator.
Fourth, aluminum cans of technological innovation
Due to the drawback that the lid of the cans could not be resealed after being pulled open, they gradually fell out. To this end, several companies in Japan began arming their rotary caps onto cans. This new type of can differs in size. Compared to the previous product, the lower part of the 300ml can is not much changed, the upper part becomes a cone and a rotary cap; the shape of the 500ml can is basically the same as the beer bottle. . Nowadays, with the popularity of this new type of can in all of Japan, consumers are increasingly showing their love for rotary caps: they can safely drink a drink and then screw the lid back into the bag. This is not what the old-fashioned cans can do. The person concerned of Mitsubishi Materials Corporation, the third largest maker of pottery in Japan, said that the new type of cans have better sealing performance and can effectively prevent beverages from coming into contact with sunlight and oxygen. In addition, it is lighter and it is also very beneficial for recycling after recycling. Japanese can makers hope to use this product to recapture the market occupied by plastic bottles. The Yamato Can Making Corporation pioneered the development of such cans in the world as early as 1999. It was first adopted by Japanese beverage companies such as Kirin Ale Wine Company. But Coca-Cola’s sale of this canned carbonated drink on a vending machine in Japan was a breakthrough in its promotion process. As a result, its sales volume has soared from 240 million in 2000 to 1.7 billion in 2002. The annual sales volume reached 2 billion. Since new cans are twice as expensive as ordinary cans, there are also concerns that it cannot be accepted by consumers in other countries because people in many parts of the world are not willing to spend more money to buy an attractive package.
In August 2004, coins packaging company developed "EPOL" (easy opening cover). This can lid is coated with a polymer-coated steel ring and heat-resistant aluminum foil, which can be used in existing filling equipment. The aluminum foil lid can be safely opened and is more suitable for the elderly and children. The two companies, Yamato Can Making and Takeuchi Stamping Industrial Co., Ltd. began researching and developing aluminum bottles and cans in 1997. They have successively developed aluminum bottled beverage containers that maintain the excellent performance of the preserved contents of the aluminum cans and are easily recycled. The newly developed aluminum cans have the following features: (1) Compared with the original aluminum cans, the appearance is beautiful and stylish, and can be re-sealed, easy to carry and easy to recycle; (2) Compared with PET bottles, light protection and barrier Significantly improve the sex, and reduce the weight of the cans by 30%; (3) The preservation performance of the loaded drinks is excellent, and the shelf life is prolonged. There are some differences in the structure of aluminum bottles and jars in the Daiwa and Takeuchi stamping industries. The product of Yamato cans is 28mm in diameter (in order to form the caliber, the bottom of the can of two-piece cans is used as the mouth); the lid, the can body, and the bottom lid are all made of aluminum; the weight of the aluminum cans (in 500ml bottles) For example), only 67% of PET bottles; the inside of the can and the bottom cover is covered with a polyester film, and the inside of the top cover is covered with a low density polyethylene. The difference between the Wune stamping industry and the Yamato can-making aluminum bottle cans is: the diameter is 38mm; the design of the tank body is smooth and easy to print. Mitsubishi Materials, after introducing the technology from the Takei stamping industry, has transformed the third production line of the Okayama Plant into a special production line for aluminum cans and entered the field. There is also a coffee hot pot that has been sold in supermarkets. Researchers are still developing cold drink cans for consumers to drink anywhere, anytime. Due to the application of new technology for the development of aluminum cans, the demand for aluminum cans may further expand in the future, and new types of aluminum cans will be more attractive in the world.
Fifth, promote the recycling of aluminum cans
Aluminium cans remanufactured aluminum, which consumed 71% less energy and 95% less air pollution than aluminum extracted with bauxite. Many countries, especially developed countries, attach great importance to the recycling and utilization of used aluminum cans after use, and the recycling rate has also been increasing. For example, the recycling rate of aluminum cans in the United States was already over 50% in the 1980s and 62.1% in 2000. The recycling rate of aluminum cans in Japan is also very high, with 43% in 1990 and 83% in 2001. At the same time, developed countries pay attention to separation and recycling in the recycling of used aluminum materials. For example, the United States classifies different aluminum scraps, sorts and re-melts used aluminum profiles and scrap aluminum cans, and then prepares them slightly to produce aluminum profiles. Aluminum strips for cans greatly reduce costs.
According to statistics released by the Aluminum Association in 2003, the recycling rate of cans in Brazil increased from 85% in the previous year to 87% in 2002, ranking first in the world for two consecutive years. The association said that in 2001, Brazil recycled 9 billion cans and weighed 121,100 tons, accounting for 47.8% of the total amount of aluminum reused in Brazil in 2001. In 2002, the turnover of the can recycling industry was R$ 850 million (approximately $270 million), of which R$ 424 million (approximately US$ 130 million) was used to purchase cans. At present, there are 150,000 people in Brazil who can pick up cans for a living. Recycling cans can save a lot of electricity. The power consumed to produce aluminum from waste aluminum is only equivalent to 5% of the aluminum used to extract aluminum from the ore. Recycling and using a can of electricity can save electricity for 20-inch TVs for 3 hours. According to Brazilian Aluminum Association statistics, in Brazil, through the recycling of cans in 2002, a total saving of 1705 GW/hour, equivalent to 0.5% of the national electricity consumption in Brazil.
The recycling technology of discarded cans has developed weakly in China, and huge waste has also been formed. This has led to the huge exchange of cans after a one-time use, immediately declared scrapped, causing huge waste. At the same time, aluminum cans that cannot be recycled have caused huge environmental pollution. The market is calling for economized raw materials that can replace aluminum cans.
At present, the international aluminum price is continuously rising. The output of domestic aluminum cans has far exceeded the demand. Three of China's 25 aluminum can-making enterprises have closed down. At present, experiments have proved that during the processing of cans, once the protective coating is peeled off, it will cause contact between the aluminum alloy on the inner wall of the can and the beverage. Over time, the aluminum will gradually dissolve, especially when the can is filled with acidic or alkaline beverages. The human body is the most dangerous. Coupled with aluminum cans polluting the environment, the country has introduced a corresponding policy, clearly stated that it will no longer approve the new aluminum can production line. In this case, steel cans and paper cans emerged as alternatives to aluminum cans.