Xiong Shoumei 1, Su Shifang 2
(1 1 Tsinghua-Toyo magnesium-aluminum alloy forming technology research and development center, department of mechanical engineering, Tsinghua University100084; 2 1 ficmes，
Shenyang, Liaoning 1 10022)
Abstract: The research and development of magnesium alloy material and its forming technology is of great significance for expanding the application of magnesium alloy in China. According to the 4th China.
According to the papers of the International Die Casting Conference, the development trends of magnesium alloy materials and their forming technologies at home and abroad are summarized, including materials, forming technologies and numerical models.
The development and application prospect of magnesium alloys are prospected.
Key words: magnesium alloy; Materials; Molding technology; numerical simulation
Classification number of China Library: TG 24912; TG 146 12 2 Document ID: A document number:100124977 (2005) 01200204.
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Research progress of processing technology
Magnesium alloy
Xiong shou 2Mei 1, su 12 Fang 2.
( 1 1 Tsinghua 2 Toyo R & amp； Meiji aluminium alloy processing technology center
Department of mechanical engineering, Tsinghua University, Beijing100084; 2 1 China foundry society
Mechanical Engineering Society, Shenyang, Liaoning, China 1 10022)
Abstract: The research and development of magnesium alloy and its processing technology is of great significance.
Importance of promoting the application of magnesium alloys in China. Conference-based
Papers of the 4th China International Die Casting Conference. Exhibition, this paper reviews this trend.
Research and Development of Magnesium Alloys and Their Processing Technology at Home and Abroad (2)
Including material development, processing technology and numerical simulation technology. exist
At the same time, the application prospect of magnesium is discussed.
Key words: magnesium alloy; Materials; Processing technology; numerical simulation
Magnesium alloys are widely used in automobile, aviation, electronics and consumer fields.
Because of this, it is difficult to be used as a key component (such as engine parts).
Various structural components in the product industry. Although the growth of these applications is mainly affected by the following factors
Materials are widely used in automobile and other industries. At the same time, magnesium alloy is dense.
Weight reduction drive, however, other advantages of magnesium alloy are also emphasized.
The hexagonal crystal structure determines its poor plastic deformation ability. How's it going?
Important role. One is their unique adaptability to die casting process.
Solving this problem is one of the keys to the application of magnesium alloys. In view of the above problems
Can produce near net shape parts at high speed; Second, excellent mold life.
Researchers have made the following progress.
The saved production cost can make up for the fact that the price of raw materials is slightly higher than that of aluminum alloy.
1 1 Development of die-casting magnesium alloy materials
The lack of high price enhances the competitiveness with die-casting aluminum alloy; Besides, very good.
Aiming at the poor creep resistance of industrial die-casting magnesium alloy at high temperature, a series of measures were taken.
Machinability and vibration damping properties of magnesium alloys are also very important.
AZ 9 1 alloy is the benchmark alloy, and he is a researcher at FAW Foundry Research Institute.
Yes China is now the largest producer and exporter of magnesium in the world, but magnesium
Member [1] developed a high-temperature creep-resistant die-casting magnesium alloy. Under discussion
Alloys are still widely used in China industry, especially in automobile industry.
The addition of rare earth elements such as cerium, yttrium, neodymium, calcium and silicon is discussed.
Limit. Therefore, magnesium alloy and its forming technology should be deeply studied.
Tensile properties and 150℃ creep behavior of cast magnesium alloys at room temperature.
Development is very important to expand the application of magnesium alloys in China industry.
For the influence of microstructure, as well as surface treatment and corrosion test.
Important significance.
Influence, as well as the actual product production.
There are more than 50 academic papers in the 4th China International Die Casting Conference.
In this paper, the chemical composition of the alloy and the solid solution of the alloy elements are comprehensively considered.
Related papers and academic reports on magnesium alloy and its forming technology.
Degree, various intermetallic compounds, while maintaining the basic composition of AZ 9 1 alloy.
There are more than 10. This paper will discuss magnesium alloy materials, forming technology and magnesium alloy.
Under the same conditions, four groups of experimental alloys were designed for research. adopt
Minutes of numerical simulation meeting of gold melt protection and magnesium alloy forming process
30 kinds of alloy test bars were trial-produced by extrusion method, and the test bars often
Research progress in related fields of argumentative writing.
The thermo-mechanical properties and corrosion behavior were tested, and the castings were preliminarily studied.
Machinability and creep resistance. Through the test, the properties of the new alloy are satisfactory.
Study on 1 magnesium alloy material
The alloy MRI2 153 recently developed by Volkswagen, Germany, and its technological properties.
Heat resistance and fatigue performance are the main obstacles to the wide application of magnesium alloys.
Equivalent to AZ 9 1 alloy, the same raw materials as AZ 9 1 alloy can be used.
Date of receipt: 20042 1 1220 received the first draft, and 20042 1 1229 received the revised draft.
About the author: Xiong Shoumei (1966-), male, from Macheng, Hubei, Ph.D., doctoral supervisor, mainly engaged in the research of die casting technology and technology. e2mail:sm Xiong @ Tsinghua 1edu 1cn
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Xiong Shoumei et al.: Research progress of magnesium alloy forming technology
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Production technology. Application of low-cost electrolytic magnesium in Shenyang Institute of Applied Chemistry
Mainly in four aspects. Among them, die casting is still the most important molding process.
-In the case of rare earth master alloy, the cost is effectively controlled. spread
The output of magnesium alloy die castings in China increased from 1995t to 1 562 t.
It is found that the strengthening phase Al 1 1Ce3 in Mg2Al2Re2Zn system exists in the solution.
In 2002, the output was 4,950 tons, which increased more than twice in seven years, with an average annual increase of1100,000 tons.
In the presence of a small amount of ca, the stability can be further improved. Add neodymium and yttrium
The annual growth rate reached 18%. The traditional cast iron is replaced by magnesium alloy die casting,
Addition will not change the grain size of AZ 9 1 alloy, but it can produce solid solution.
Steel castings, even replacing aluminum die castings, are becoming a manufacturing industry, especially steam.
Strengthened, with excellent creep performance.
The development trend of automobile manufacturing industry [4].
Study on low cycle fatigue behavior of 1 12 die-casting magnesium alloy
Die casting of 2 1 1 magnesium alloy
Researchers at Shenyang University of Technology [2] found through experiments that stress
At present, the research focus of magnesium alloy die casting technology mainly focuses on two aspects.
The fatigue life of as-cast AZ 9 1 is the lowest; Under the condition of high strain amplitude, die casting
Main aspects: magnesium alloy die casting development and design, magnesium alloy die casting workers.
The fatigue life of as-cast AM50+Nd is higher than AZ 9 1, but lower than AZ 9 1.
Perfection and innovation of art. With the level of mold design and the performance of die castings
Under the condition of strain amplitude, the life of as-cast AM50+Nd is shorter than that of as-cast AM50+Nd.
Improving the application field of magnesium alloy die casting from traditional notebook.
Fatigue life of AZ 9 1 after solution treatment: solution treatment
Surface coverings such as computer housings and mobile phone housings have been developed to engine supports.
The transition fatigue life of AZ 9 1 magnesium alloy is obviously higher than that of die casting and die casting.
Frame, wheel hub, frame parts and other stress parts, as well as safety parts.
The transition life of as-cast AM50+Nd magnesium alloy is longer than that of as-cast AZ magnesium alloy.
Therefore, in order to meet the increasing performance requirements of parts, with
9 1。 After solution treatment, the β phase in AZ 9 1 disappears, which makes the material
With the progress of material science and other science and technology, in the traditional die casting process,
With the increase of ductility, the cyclic hardening degree decreases.
Vacuum die-casting, oxygen-filled die-casting and ultra-low speed die-casting are carried out in.
Study on as-cast microstructure of 1 13 magnesium alloy
And many other branch technologies. Among them, vacuum die casting is characterized by extremely low gas content in castings.
When magnesium-aluminum alloy is not modified, the as-cast grain size can be
Good quantity, good equipment compatibility and excellent casting performance.
Up to 3× 10 ~ 5× 10 m, the structure is very rough. Determination of microstructure of alloy
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Attach great importance to and develop vigorously. As we all know, the porosity of die casting is required.
Properties determine the application of alloys, and the microstructure of magnesium alloys used to be controlled.
The problem is the main bottleneck that limits its performance improvement. Vacuum die casting under traditional pressure
The system is mainly to improve its plastic deformation ability. Because magnesium alloys are dense
It is a reduction to remove the cavity gas in the casting process cycle by coupling vacuum system.
Hexagonal arrangement, which determines its poor plastic deformation ability. Practice proves
There are few air holes in die casting, which can effectively eliminate the gas and lubricant vapor in the die.
Bright and fine equiaxed crystals can improve the plastic deformation ability of magnesium alloys. but
Method. At present, the focus of research is how to obtain higher truth value in the cavity.
Semi-solid thixoforming also requires that the initial as-cast structure should be fine and so on.
Voids, and the corresponding mold sealing process. High vacuum pressure casting.
Axial crystal structure, so how to control the microstructure of magnesium alloy is semi-solid magnesium alloy.
This part can not only greatly reduce the casting defects such as air holes and micropores, but also
One of the keys to the formation of a country.
Heat treatment and die casting welding can be carried out [5].
The commonly used microstructure control technology of magnesium alloy mainly includes liquid treatment and
The researcher of Shenyang University of Technology [6] studied the die-casting magnesium alloy.
There are two solid-state processing methods. The liquid treatment method is simple and feasible.
The causes of wheel hub defects are analyzed from two aspects: gating system and part structure.
At present, it has a broad industrial application space without adding additional equipment.
The improvement and adjustment of die casting process parameters effectively simulated the defects.
Between. The liquid treatment method includes adding grain refiner and overheating treatment.
The quality of die-casting magnesium alloy wheel hub parts is obviously improved.
Method, melt mixing method two categories. Solid state treatment includes isostatic pressing.
Tsinghua University researchers [7] cooperated with FAW to conduct systematic research.
(ECEA) method, large proportion extrusion method and powder casting method. But for Israel,
The effects of various die casting process parameters on the quality of magnesium alloy die castings were studied.
The mechanism of these methods is still unclear, or these methods are being tested.
Method, successfully developed the first magnesium alloy die casting of FAW Group and put it into practice.
Stage. The lack of understanding of the microstructure control mechanism of magnesium alloys leads to a problem.
International production. At present, magnesium alloy vacuum die casting and ultra-low speed die casting are being carried out.
Because of some confusion, the microstructure control of magnesium alloys in industry mainly depends on classics.
Experimental research.
Test method [3]. Up to now, the research on microstructure control of magnesium alloys
2 12 low pressure casting
The research mainly focuses on the role of foreign particles in promoting nucleation and inhibiting crystallization.
Low pressure casting is characterized by smooth filling process and good exhaust.
Effect of grain growth and solute on nucleation rate. In magnesium alloy melt
Performance, widely used in wheels and other parts sensitive to casting defects.
Add a small amount of inoculants (magnesium carbonate, carbon chloride, ferric chloride, etc.). ) or
Parts manufacturing. Compressed air used in the traditional low-pressure casting process includes
Solute atoms (zirconium, calcium, strontium, rare earth, etc. ) can refine the casting of magnesium alloys.
Oxidation and inhalation caused by insufficient gas purity and high oxygen partial pressure.
The microstructure is formed and the morphology of precipitates is changed to improve the mechanical properties of magnesium alloys.
It will cause problems such as oxidation inclusion, microcrack, shrinkage cavity and blowhole.
Yes, it can improve the working performance under pressure. However, the research on microstructure refinement of magnesium alloys
And other casting defects limit the popularization of low-pressure casting. Charging with electromagnetic pump
The research and application are far less than that of aluminum alloy, which deserves further study.
New low-pressure casting technology with electromagnetic pump filling technology as the core
The heart, when filling and maintaining pressure, uses non-contact electromagnetic force to move linearly.
Research and development of magnesium alloy forming technology
It acts on liquid metal to realize the smooth transportation and mold filling of aluminum liquid.
At present, the forming process of magnesium alloy is still casting by pressing force.
The secondary pollution caused by turbulence is avoided and a high casting rate is obtained.
(HPDC), low pressure casting (L PDC), squeeze casting and semi-solid casting.
Single piece quality. At the same time, the computer control system is introduced to improve the process execution.
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Accuracy, also make the production efficiency has been improved [8]. In addition, by
Based on the principle of integral protection, the shortcomings of various mixed gas protection are discussed.
Open-loop control mode used in low-pressure casting process of electromagnetic pump control
In this paper, the effects of different proportions, different temperatures and operating conditions were studied.
High precision, aiming at the determination of process parameters and electromagnetic settings
The protective effect of HFC2 134a gas on liquid magnesium alloy was studied.
A series of research work has also been carried out on the development of [9]
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The related process parameters and protection technology are introduced. The results show that HFC2
2 13 semi-solid casting
134a gas has better protection characteristics than SO2 and SF6,
Semi-solid casting technology has been widely concerned since its birth.
It can be used as the first choice for magnesium alloy melt gas protection.
Note that it is the frontier of research. Because this technology is more dependent on equipment.
Numerical simulation of die casting process of magnesium alloy 4
At present, the research focus is mainly on the improvement and perfection of equipment performance.
Let's go The newly developed second generation thixoforming machine has the highest injection speed.
In the process of magnesium alloy die casting, liquid or semi-solid metal
5 m/ s, its key parts such as screw and sleeve are made of new alloy, which is corrosion resistant.
High-speed and high-pressure mold filling, high-pressure rapid solidification and easy production.
The high temperature and thermal conductivity are improved, and the rigidity and speed of the mode locking mechanism are improved.
Casting defects such as air holes. Because the filling speed of magnesium alloy die casting is higher than that of aluminum alloy
Strengthen, reduce energy consumption, and obtain higher casting quality and quality.
The higher the gold content, the faster the solidification speed. Therefore, magnesium alloy die casting has a great influence on the mold.
Productivity [1 1]. At the same time, the research on thixoforming method has also promoted
Higher requirements are put forward for runner system and heat balance design. Fully understand
A number of new technologies such as hot runner system and long nozzle have been put into use.
The law of flow and heat transfer during mold filling, and the reasonable design of castings and molds.
Technology, thixoforming forging process and so on.
Structure and gating system, choosing appropriate die casting process parameters, can not only
2 14 squeeze casting
In order to reduce the rejection rate of castings and improve the quality and production efficiency of castings.
Squeeze casting belongs to the field of magnesium-aluminum alloy materials, and the casting quality is high.
The service life of the die can be prolonged. The numerical simulation method is used to solve the above problems.
Quality, high mechanical properties and high density have always been concerned. squeeze
Problems provide effective means. Through the flow field, temperature
Casting can make parts with any wall thickness undergo solution heat treatment, thus obtaining
The numerical simulation of degree field can accurately express the filling process of die casting
The mechanical properties are higher than those of traditional die casting. On the other hand, squeeze casting can
Flow and heat transfer law, realize the ideal cavity filling state and die heat dissipation.
In order to use pressurized method in solidification process, it is superior to low pressure casting.
Balance state, predict possible defects such as air entrapment and cold preservation, and then
Dense structure of castings. At the same time, the density of squeeze casting and semi-solid casting
Optimizing the die casting process is of great guiding significance to the actual die casting production.
This connection also makes this technology a research hotspot. Current squeeze casting
Justice. Therefore, computer simulation technology has been widely used in magnesium alloy stamping.
The main problem is that the requirements for technology and process control are too high.
Mold design and process analysis of castings.
Our investment is relatively high. At present, the research focus is mainly on extruded roof.
Researchers in Tsinghua University [4] have been engaged in the simulation of die casting process for a long time.
The application of needle and absorber, the selection of extrusion position and the control of process parameters.
The research work of simulation technology, and successfully applied simulation technology to magnesium.
System and other aspects [12].
Die design optimization, thermal balance analysis and thermal stress of alloy die casting parts
Squeeze casting can be achieved by using special equipment or
Force and deformation analysis. At the same time, especially for the liquid metal flow in the pressure chamber
On the traditional die casting machine. He solved the problem that the traditional die casting machine could not produce.
The dynamic simulation was carried out, and the low injection speed and the filling condition of pressure chamber were systematically studied.
Shrinkage and porosity are common problems in thick and large parts and die castings, which can be used to produce various kinds of
The parameters such as fullness are related to the gas in the air pressure chamber, and on this basis, it is put forward
Alloys with different strength and fluidity simplify the design of die casting die.
The optimization process of low-speed injection is introduced.
Ideas, reduce the cost of die-casting die for simple parts, and make small and medium batches
Researcher of Shenyang University of Technology [15]
- 16〕
Using FLOW3D
A large number of parts can be produced by die casting process. By squeeze casting technology
The filling process and solidification process of different magnesium alloy castings were simulated.
On this basis, the traditional casting, low pressure casting and traditional squeeze casting equipment are introduced.
This analysis provides a reference for die-casting die design and defect location prediction of magnesium alloy.
The transformation of this line contributes to the popularization of squeeze casting technology [13].
Under the guidance of theory, the quality of magnesium alloy die castings has been effectively improved and reduced.
Mold design cost.
3 magnesium alloy melt protection
5 concluding remarks
Gas shielded melting technology of magnesium and magnesium alloys is currently used to produce high purity.
Key technologies of high quality magnesium alloys. More than 20 years ago, in smelting
With the wide application of magnesium alloy die casting, its die casting performance has been improved.
When magnesium and magnesium alloys were used as protective gases, it was the magnesium industry at that time.
And creep resistance at high temperature has become an important research topic. our country
The biggest progress. Because it eliminates the previously used SO2 and flux melting.
Rare earth resources are abundant, rare earth magnesium alloys have excellent properties and broad development prospects.
Most problems in the refining process. But it's 1990, SF6 and Ban.
Die-casting rare-earth magnesium alloy with China characteristics improves its high-temperature creep resistance.
High greenhouse effect of simulators (24,000 times that of CO2, and can be increased on a large scale)
Yes, it means a lot.
Gas exists for 3 200 years), forcing users in magnesium industry to look for technology.
Die casting is the most important forming process of magnesium alloy.
Alternative protective gas with feasible operation, economy and environmental protection. Looking for SF6
The quality of high magnesium alloy parts and the expansion of application fields of magnesium alloy should be
Substituting shielding gas is an important topic in magnesium industry at present.
Actively carry out some new molding processes (such as vacuum die casting, ultra-low
North China Institute of Technology [14] researcher is discussing magnesium alloy melt gas.
Rapid die casting, extrusion casting, semi-solid casting and other molding methods).
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Research work. Magnesium alloy forming technology puts forward higher requirements for technological process.
Proceedings of the 4th China International Die Casting Conference [c]. Beijing: Machinery Industry Press,
Requirements, numerical simulation technology can be used to optimize the forming process (die design
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(Editor: Qu Xueliang, qxl @foundryworld 1com)