Development and research of new products and new process technologies for aluminum and aluminum alloys

First, the new aluminum alloy casting technology progress

In recent years, the development of aluminum alloy melting and casting equipment tends to be large-scale and highly efficient. The melting furnace generally adopts a circular-opening furnace instead of a rectangular furnace, which shortens the charging time of the charging material, reduces the labor intensity of charging, and improves the distribution of the charging material in the furnace. Uniformity, and the use of large-capacity melting furnaces and static furnaces. The biggest improvement of the melting furnace is in the combustion system: on the one hand, the medium and high speed burners (burning speed 30-300 m/s), on the other hand, the waste heat recovery device-heat exchanger is generally used to recover part of the waste heat and preheat the combustion air.

Some specific new technologies are as follows:

(1) Melt purification technology: The development of this technology is mainly the on-line processing system of the widely used on-line processing technology, which is the comprehensive application of degassing and slag removal methods in the melt supply process. The following examples are illustrated:

Caesar Aluminium Company of the United States: static furnace → (Al-Ti-B) → SNIF → filter plate → glass filtration → casting.

Australia: Lomalce static furnace → (Al-Ti-B) → glass filtration → Alpur → glass cloth filtration → filter plate → casting.

China Southwest Aluminum Processing Plant: static furnace → (Al-Ti-B) → DAC pretreatment → MINT → glass filtration → casting.

(2) Melt hydrogen measurement technology: Advanced melt can reliably grasp the hydrogen content in the melt. At present, the world's most advanced aluminum melt hydrogen measuring instrument is still Alcoa Telegas II instrument, Canadian ALSCN instrument, Japan Friends of the metal company SLM instruments, but these three instruments exist ceramic probes are easy to break, the probe is expensive, the ELH-III type hydrogen measuring instrument developed by the Southwest Aluminum Processing Plant and its improved HAD hydrogen measurement instrument.

(III) Foundry technology: The most advanced technology for aluminum and aluminum alloy semi-continuous casting is electromagnetic casting. The development of adjustable crystallizer is also a new trend in the development of casting technology.

(4) Grain refinement treatment technology: Al-Ti binary alloy and Al-Ti-B ternary intermediate alloy are mainly used as grain refiner.

(5) Advances in ingot technology. (1) electromagnetic casting; (2) gas-slip method; (3) same-level casting; (4) gas-pressed hot-top casting method; (5) CO ₂ cooling method; (6) capsule scraping; (7) electromagnetic Stir.

Second, the new development of rolling technology

The new progress in rolling technology is as follows:

(1) Table convexity and shape control technology are shown in Table 1.

Table 1 Main board convexity and shape control technology

(2) High-speed rolling technology: With the thinning of sheet materials and the increase in the size of coils, in order to ensure the improvement of productivity, the speed of cold rolling mills has been actively promoted, and the degree of rolling production has now reached 2000 m/min.

(3) Continuous rolling technology: There are two kinds of aluminum continuous casting processes: (1) continuous casting and rolling; (2) continuous casting.

Third, the new development of extrusion technology

At present, the new extrusion technology is still mainly reverse extrusion, isothermal extrusion and Conform continuous extrusion and Castex continuous extrusion technology.

Fourth, the progress of aluminum foil production technology

Lead foil production technology progress is as follows:

(1) The rolling speed is high, and it has exceeded 1500m/min.

(2) The billet is large and has reached 25t volume.

(3) Machinery and automation: automatic control of aluminum thickness, automatic transfer of coils, automatic stop of broken belts, rapid roll change, etc.

(IV) New type of lubricant: At present, low flash point light mineral oil is generally used to add polymer additives of different concentrations.

Five, new products

(1) Foamed aluminum alloy

The alloy is a new building decoration material, high-grade packaging material, foam aluminum made by direct foaming method or powder pressing + high temperature foaming, light weight, heat resistance, non-combustible, sound insulation, heat insulation, corrosion resistance, anti-electromagnetic interference, It can be used as partition walls, curtain walls, shield walls, ceilings, floors and high-grade packaging materials inside and outside buildings.

(2) Honeycomb structure aluminum alloy composite board

It is an ideal exterior wall decoration material. The inner layer is made of aluminum foil, glass fiber reinforced plastic or paper honeycomb, and the outer layer is made of aluminum alloy sheet.

(3) Aluminum-plastic composite board and composite pipe

The plastic polyethylene is used as the substrate, and the panel and the bottom plate of the aluminum foil aluminum plate are composited by a certain process, and the surface treatment is adopted to make it light in weight, corrosion-resistant, fireproof, moisture-proof, bendable, easy to construct, beautiful and elegant, and lustrous. widely used in building walls, cylindrical, angular decoration, the die; plastic composite pipe is mainly used in industrial buildings water, coal pipe.

(4) Aluminum air battery

As an aluminum-air battery (plate material), one of the candidate power sources for electric vehicles (ideal vehicles), American Electric Technology has successfully tested it on cars.

(5) Aluminum for automobiles

According to the survey by the American Aluminum Association, by 2005, the global automotive consumption of aluminum will reach 10 million tons, which is three times the current.

(6) Superplastic aluminum alloy

Superplastic aluminum alloys were first studied in the early 1960s, mainly some eutectic aluminum alloys or eutectoid aluminum alloys. The superplastic aluminum alloys that have been developed for industrial use and have excellent corrosion resistance are attracting people's attention.

(7) Aluminum- lithium alloy

Al-Li alloy has achieved the function of reducing structural weight in the aerospace industry, opening up a new alloy system for the aerospace industry. The main components of the alloy are shown in Table 2.

Table 2 Composition of aluminum-lithium alloy (%)

(8) Cans blanks

3004, 5082, 5042 aluminum alloy special thin strip.

1, aluminum alloy function touch technology

Aluminum alloy functional film technology has:

(1) Computer disk diaphragm: 2 light/heat conversion film of solar water heater; (3) electric/color conversion film; (4) insulating film; (5) wear-resistant lubricating film;
(6) Mirror film.

2, magnesium aluminum alloy matrix composites electronics package

Due to the low density of the aluminum-magnesium alloy matrix composite, the quality of the device can be greatly reduced, the thermal conductivity is larger than that of the iron- nickel alloy, the coefficient of linear expansion is small, and it is controllable, and has strong corrosion resistance, and has great application prospects.

3. Development of aluminum for electronic instruments

The development of aluminum for electronic equipment is as follows:

(1) The magnetic disk substrate is a base plate on which a magnetic film is mounted, and has been put into practical use. Table 3 lists the aluminum alloy components of the magnetic disk substrate, using a high-purity aluminum ingot as a substrate and the most stringently treated Al-Mg. alloy.

Table 3 Chemical composition of aluminum alloy for disk substrate (mass fraction /%)

(2) Photosensitive drum. The aluminum alloy tube for the photosensitive drum support of the electrophotographic copying machine and the laser Printing Machine, the aluminum magnetic drum processing method and the alloy used therein are shown in Table 4.

(3) copper-clad laminated boards aluminum foil: aluminum foil laminated boards and the packet is processed into a printed wiring board with rapid cooling, and processing characteristics such as electron shielding effect.

4, electrical aluminum

Aluminum used as a conductor began in 1876, developed countries in Europe and America used aluminum as a distribution line after 1995. The amount of aluminum used in China's electrical sector accounts for about one-third of the national aluminum consumption. It is known that the development of electrical aluminum, a large number Advocating aluminum to copper has great economic value.

5. Aluminum for communication engineering

At present, the demand for electronic communication equipment for vehicles, such as car radios, telephones, computers and radio transceivers, is further increased. In order to reduce the quality of the vehicle body, save energy and facilitate high speed, it is inevitable to use a large amount of lightweight aluminum alloy materials. Typical applications for aluminum in communications are as follows:

Table 4 Aluminum drum processing method

(1) Antenna: Most communication satellites and aircraft navigation antennas are made of LD31 alloy extruded profiles and LF2 alloy plates. The main reason is that these two alloys have good corrosion resistance, good electrical conductivity and medium strength. Communication equipment is an industry field that is rapidly developing in the future, and aluminum will use more and more aluminum in these areas.

(2) Waveguides: TV broadcasts and aircraft uniform microstrip waves require waveguides, usually made of rectangular cross-section tubes. Waveguides require good electrical conductivity, corrosion resistance, machinability, weldability and dimensional accuracy. Available L2, LF21 and LD31 alloy extrusion, and chromic acid anodized or coated with anticorrosive material.

Waveguide production process is as follows: → machining → degreasing → etching → decontamination zincate plating electroless copper plating → → → plated copper pyrophosphate plating surface protective metal → → adjustment assembly.

(3) Optical polyhedron: The optical polyhedron is first used in laser printing machines, and later used for measurement and image processing. It is usually used as an optical polyhedron ultra-precision turning material with 8, 10, 12-sided aluminum alloy rotating polyhedral mirrors. Developed into a highly unified Al-Mg alloy.

(4) Capacitors: Aluminum foils, sheets and wires are used in electrolytic vessels, paper capacitors and organic film capacitor industries. These aluminum capacitors are widely used in various household appliances, audio equipment, magnetic tapes, video recorders, and lighting fixtures. Electronic musical instruments, optical instruments, communication equipment, office supplies, automobiles and automation.

6. Development of aluminum materials for automobile vehicles

The world's high-speed industrialization process has accelerated the energy crisis. In order to reduce gasoline consumption, the automobile industry has proposed a lightweight vehicle solution. As a result, automotive aluminum and automotive industries have become more mature with aluminum-based copper solutions. In addition, from improving vehicle driving performance and passenger comfort. In terms of sex and safety, automotive aluminization is an inevitable trend. Since aluminum is an ideal material for lightweight vehicles, automotive aluminization has become a worldwide issue.

In order to greatly reduce the weight of the car, people's research focuses on the body (about 30%), the engine (about 18%), the drive train (about 15%), the walking system (about 16%), and the wheel. (about 5%) and other aluminum parts of steel parts.

7. Aluminum for railway vehicles

With the advancement of science and technology and economic development, the requirements for high-speed, large-scale and lightweight of railway vehicles have also created conditions for the development of aluminum alloys. In railway vehicles, aluminum alloy is mainly used as the structure of the car body. In the aluminum alloy car body, the profile accounts for about 70% of the total, the plate accounts for about 27%, and the cast forgings account for about 3%. Aluminum alloy components have also been widely used in subway vehicles. Many countries have used semi-aluminum or all-aluminum bodies, and aluminum convertibles have also been developed.

8. Application of aluminum in the packaging industry

Aluminum is widely used in the packaging industry. The packaging of beverages, cigarettes, food, cosmetics and medicines uses a large amount of aluminum and aluminum foil every year. Now the world's aluminum consumption accounts for 20% of the total aluminum consumption. Aluminum rights account for 5% of consumption. Since 1986, the packaging industry has used about 60,000 tons of aluminum per year. The more used ones are cans and tobacco. The amount of aluminum used in China's packaging industry in 1995 and 2000 is shown in Table 5.

Table 5 Amount of aluminum used in China's packaging industry in 1995 (2000 t)