Development and application of the hottest aluminu

The development and application of aluminum in packaging and container industry

Abstract: This paper introduces the development of aluminum in packaging and container, and focuses on the application and development of aluminum alloy cans and packaging aluminum foil. It is pointed out that aluminum alloy material is still one of the main materials for all kinds of hard packaging and soft packaging. Key words: production and consumption of aluminum packaging materials; Hard packaging and soft packaging; Cans; High precision ultra thin aluminum plate; Aluminum foil; Development and application

1 overview of the development of aluminum materials for packaging and containers

aluminum is widely used in the food industry and pharmaceutical industry because it is non-toxic, non absorbent and can prevent fragmentation. It can also minimize the growth of bacteria, generate colorless salts, and accept steam cleaning. When containers and conveyor belts enter the heating or freezing zone, the low volume specific heat of aluminum can produce energy-saving value. The non sparking nature of aluminum is valuable for flour mills and other factories vulnerable to fire and explosion hazards. The corrosion resistance of aluminum is also important in the shipment of fragile goods, valuable chemical reagents and cosmetics. Designed for air, shipping, train and truck shipment, sealed aluminum containers can be used to ship chemical reagents that are not suitable for bulk

the packaging industry has always been an important market for aluminum. The result shows that the maximum force exerted by penetrating the gasket represents one, and it has developed rapidly. Packaging products include household packaging materials, flexible packaging and food containers, bottle caps, hoses, beverage cans and food cans

aluminum beverage cans are the most successful application in the history of aluminum industry. The signal line connecting software and servo machinery is also accelerating the penetration of aluminum food cans into the market. Soft drinks, beer, coffee, fast food, meat, and even alcohol can be packaged in aluminum cans. Draft beer can be shipped in aluminum barrel. Aluminum is widely used in the manufacture of flexible tubes for toothpaste, food, ointments and pigments and flexible packaging bags for drugs. To sum up, the main forms of aluminum used for packaging are:

① flexible packaging bags made of aluminum foil, which are used in the food and pharmaceutical industries and cosmetics industries; ② Semi rigid containers (boxes, cups, cans, dishes, small boxes) made of aluminum foil; ③ Household aluminum foil and aluminum foil for packaged food; ④ Sealing caps of metal can boxes, glass bottles and plastic bottles; ⑤ Rigid aluminum cans, especially two-piece aluminum beer cans and soft drink cans (hard packed cans); ⑥ Composite foil container; ⑦ Soft tubular containers, etc; ⑧ Large rigid packaging containers, such as containers, refrigerators, beer barrels, oxygen cylinders and liquefied natural gas tanks, etc

the aluminum consumption of aluminum cans in the United States was 650000 tons in 1975 and more than 1million tons in 1980. In 2005, the total production of all aluminum cans in the United States was about 130billion, the consumption was more than 100billion, and the consumption of aluminum materials was more than 2million tons, accounting for about 41% of the total output of aluminum plates and strips in China (4.65 million tons), and the export volume accounted for about 13%, which was in a stable period of development (annual growth of 1% ～ 2%)

in 2005, the production and consumption of aluminum can materials in Japan was about 440000 tons, including 140000 tons of tank cover and pull ring and 300000 tons of tank body materials, which was also in a stage of stable development (with an annual growth rate of about 2%). In 2005, the production and consumption of aluminum cans in Europe was about 1.2 million tons, 11.15 million tons in South Korea, 11.15 million tons in Brazil and about 100000 tons in other countries. The annual growth rate of these countries is about 5% - 10%. At present, the global total annual output of aluminum can materials has reached about 4.3 million tons, including 2.89 million tons of can body materials and 1.41 million tons of can cover and pull ring materials. Except that the United States, Japan, Europe and other countries and regions have been in a relatively stable development period, China, Brazil, India and other countries are still in a period of rapid development. Therefore, the global annual growth rate will remain above 8%

the history of aluminum cans in China is not long and the foundation is poor, but it has developed rapidly in recent years, reaching 10.3 billion in 2005, with an average annual increase of 1715%. It is estimated that it will reach 18billion by 2010, and will increase by 10% for several years. In 2005, there were 22 production lines of 16 can making enterprises in China, with an annual total production capacity of 11.5 billion. It is expected that in the near future, China will not only be a major producer of aluminum cans, but also a major consumer of aluminum cans

$page break $2 technical development and application of aluminum pop-up cans

2.1 application of aluminum pop-up cans

at present, the U.S. container packaging industry accounts for about 25% of the total U.S. aluminum consumption (about 40% of rolled products), and all aluminum two-piece beverage cans account for more than 3/4 of the total beverage can market, 80% of the beer market, and 60% of soft drink cans. The aluminum consumption of Australia's container packaging industry accounts for more than 28% of its total aluminum semi-finished products, and aluminum cans account for 75% - 80% of the beer market and more than 72% of the beverage can market. The proportion of aluminum cans in Western Europe, Japan and other countries is relatively small, but it has increased rapidly in recent years, especially the production and consumption of aluminum cans in Japan have developed rapidly. In 2005, the world's aluminum consumption of packaging containers accounted for more than 20% of the total global aluminum output, which is one of the aluminum consumption

China's per capita consumption of cans (318 cans/person · year) is still very low, only about 1/100 of that of the United States (380 cans/person · year), but it is developing rapidly. In 2005, China consumed a total of 10.3 billion cans, equivalent to 150000 tons of aluminum strip (012 undeniably 8mm), 70000 tons of cover materials and pull rings, a total of 220000 tons, and the tank body: tank cover (ring) = 68:32. It is estimated that it will be 390000 tons in 2010 and 62.15 million tons in 2015. It can be seen that China's cans market still has broad development space

2.2 quality requirements of aluminum for easy pull cans

the production of aluminum easy pull cans requires more than 40 processes. The main processes related to the performance of aluminum sheet include: blanking, cup punching, thinning and deep drawing, trimming, washing, external printing, internal spraying, drying, necking, flanging, etc. Aluminum sheet must have appropriate strength and good deep drawing formability to ensure the continuous punching, thinning and deep drawing process and the yield strength after baking. Among them, the sheet metal with thickness of 0125mm ~ 0130mm is punched into a round material with a diameter of about 138mm, and then a punching cup is formed by deep punching twice, with a diameter reduction rate of more than 50%. After three times of thinning and deep drawing, the wall thickness is reduced to 0108mm ~ 0110mm, and the tensile thinning rate is more than 65%. Because thinning and deep drawing can make the ductility of the blank in a very low state, even small inclusions will become the cause of fracture and flanging. Then it is necessary to ensure that there is no fracture during trimming, necking and flanging, and the material is also required to have good plasticity. After several times of baking, it is also necessary to ensure the axial pressure of the tank body and the pressure resistance of the tank bottom. It is required that the axial pressure strength of the tank body is 1135kn and the pressure resistance strength of the tank bottom is 630kpa, so as to make the canning, storage and transportation smoothly. Therefore, quite strict requirements are put forward for the comprehensive properties of aluminum plates for tanks: tensile strength 270 ~ 310mpa, yield strength 250 ~ 300mpa, elongation greater than 3%, ear making rate less than 2%. There is no obvious ripple on the surface of the plate, and the internal and external surface finish should be uniform, free of oxidation, visible inclusions, bruises, spots and other defects. The plate thickness shall be uniform and the tolerance shall be within 01005mm

lightweight has become an inevitable trend in the development of cans (Figure 1)

with the continuous progress of seam sealing machinery and other technologies in can making enterprises, the thickness of aluminum in can body has been reduced from 01343mm in the last century to 01259mm; The aluminum material of the tank cover also decreased from 0139mm to 0124mm. In order to improve production efficiency, can manufacturers are also relying on advanced technology to continuously improve the forming speed of cans. In the mid-1980s, the forming speed of cans in the United States was about 800 cans/minute, while at present, the forming speed of production lines has reached 2000 cans/minute

to sum up, with the continuous improvement of production technology, the lightweight of cans and the improvement of forming rate, more stringent requirements are put forward for the performance of aluminum alloy plates. Only by continuously improving the accuracy, surface quality, internal metallurgical quality and formability of aluminum sheet can it meet the production needs of cans

2.3 main factors to improve the quality of aluminum can materials and Technological Development

the production process of high-precision aluminum alloy plates mainly includes smelting

casting, milling, homogenization and heating, Hot Roughing, hot finishing, finishing, shearing, annealing and other technological processes. In order to make aluminum materials have good deep drawing forming performance, fatigue resistance, corrosion resistance, excellent surface quality, high strength, sufficient plasticity, small ear making rate and strict dimensional deviation, the materials are required to have appropriate chemical composition, excellent metallurgical quality, reasonable texture and shape tolerance. To meet these requirements, it is necessary to effectively control every link in the whole production process of aluminum sheet, among which the composition control, aluminum melt treatment and hot rolling process optimization are the key links to improve the quality of aluminum

at present, 3104 alloy is mainly used as tank material in various countries, which contains about 1% Mn and Mg respectively. Adding Mn can improve the strength of the alloy. When Mn is lower than 015%, the strength is insufficient, but when Mn is higher than 2%, coarse primary crystal compounds are formed in the crystallization process of Al - Mn - Fe alloy, which makes the formability of the material worse, and pinholes or tears may be formed during the forming of the can body

mg can improve the strength of sheet more effectively than Mn. When mg is lower than 012%, the strengthening effect is insufficient. Increasing Mg content can improve the yield strength of the plate, but when mg is higher than 2%, the thinning tensile capacity of the plate and the formability of the bottom flange of the tank become worse, and it is easy to cause scratches on the tank body during stretching

si can promote the transformation of primary compounds into α Phase, improve the thinning tensile ability, and at the same time, Si also forms Mg2Si precipitated phase with Mn to improve the strength of the plate, so the Si content must be more than 011%, but not more than 015%, otherwise the processability will be reduced

fe and Mn form (FeMn) al6 compound, which is beneficial to stretching. Therefore, its content should be greater than 012%. However, we have achieved the industry leader's sales volume in 2016. When it is greater than 017%, the formability will deteriorate

cu can not strengthen when it is lower than 0105%, but it will reduce the corrosion resistance when it is greater than 015%

in order to avoid the formation of coarse intermetallic compounds, the contents of Fe, Mn and Mg in DC ingots should meet the following relationship: Fe wt% + (Mn wt% × 1107) + (Mg wt % × 0127)