As one of the important components in the military driving system, the wheel not only carries the weight of the military, but also reflects the appearance of the military vehicle
1. It is safer, more energy-saving, less noise and more stringent requirements for pollutant emission to adapt to Qin cars. The lightweight of automobile wheels has become a trend in the world. The main measures to reduce the weight of the pen hub are the use of lightweight materials and new processing methods. Aluminum alloy wheel casting and spinning process background Aluminum alloy is more and more widely used in the car replacement industry, especially in the application of aluminum alloy wheels. The effect of using aluminum alloy wheels on the car is obvious. The aluminum alloy wheels used on radial cars are 30%-40% more than traditional steel wheels. In addition to the advantages of light weight, low cost, and high strength, the aluminum alloy wheels also have stronger heat conduction. Performance can greatly extend the life of vehicle tires, especially the life of high-load truck tires. The aluminum alloy wheel has a large diameter, light weight and high strength. There are many kinds of forming methods. The main methods used at home and abroad are low jade casting, gravity casting and extrusion casting, and liquid die forging, hot die forging and semi-solid forging. Based on cost considerations, forged wheels are used in high-green cars. Most ordinary cars use cast wheels and the material is A356.
On the basis of the existing production technology, equipment and process of aluminum alloy A356 for automobile wheels, we propose new manufacturing processes and develop new forming technologies to develop high-strength and lightweight wheels. It will become a light-weight automobile. The following research hotspots. In the late 1990s, Japan used the spinning E process for the forming of cast wheel blanks.
Kai loves the new technology of casting and spinning of alloy wheels. That is, low pressure casting + wheel copper hot pressing (casting spinning). It is currently the safest, most economical and applicable method of wheel processing. Low-pressure casting can meet the appearance requirements. The rim has been formed by hot spinning, and there are obvious fiber flow lines in the structure, which greatly improves the strength of the inner color edge of the wheel and the corrosiveness of the structure of the copper parts.
The organization of each part of the alloy wheel hub. Due to the use of spinning technology, the cast and wheel wheels have the characteristics of each part; the performance index can be significantly higher than the low-pressure poetry building army. And while meeting the strength of the wheel, the wheel steel wall can also be greatly thinned .Realize the high strength and light weight of the product, with stronger competitiveness and broader market prospects. In terms of spinning equipment, process, design technology, Li Shu provides a strong technical guarantee for the production, research and development of cast rotary wheels. The spinning process will be one of the main aspects of the development of the process development of the flat aluminum alloy wheel. —.
2. Casting spinning aluminum alloy wheel technology
Principle of Pass Rotary Wheel Casting of aluminum alloy wheel hub with 3m second-rotation wheel casting is the hot-spinning process for casting rough wheels. The principle of the forming process is to spin the upper die to compress the casting billet, so that the casting billet and the lower die rotate synchronously. Surface fit. Obtain the actual required wheel shape. In the spinning forming process, only the wheel steel is deformed, and the spokes play a role of fixing and supporting during spinning.
The arrangement of the rotating wheels—generally there are two pairs of 120 and pin-shaped.
At present, most of the three-wheeled 120° arrangement is adopted, which mainly considers the balance of forces during the spinning process. Before spinning, it is necessary to set the process parameters of the rotary wheel motion trajectory, the thinning rate of the rotary wheel each pass, and the feed rate.
3. Process flow of cast-rotating aluminum wheels
Compared with ordinary low-pressure casting wheels, cast rotary wheels have four more milling, pre-machine adding, blank heating and spinning, and blank cooling processes.
4. Factors affecting casting spinning process
There are many factors that affect the hot spinning forming process of aluminum alloy wheel casting blanks, such as process steps, mold design, total deformation, thinning rate of each pass, forming temperature, rotary wheel feed rate and so on.
4.1 Work steps, mold design
The particularity of the casting spinning process determines that the blank design adopts the reverse thrust principle, that is, the spinning blank is first designed, and then the casting blank is designed. Two sets of molds are required to cast the rotary hub, one set of low pressure casting mold and one set of spinning mold. The design of the casting blank must take into account the design of the low-pressure casting mold to ensure the stability of the low-pressure casting process.
The most important thing in the spinning process is the degree of adhesion between the mold and the blank. The degree of adhesion between the mold and the spinning blank is limited.
Numerical simulation of elementary thermal analysis puts forward a more reasonable thermal expansion coefficient of the mold.
The mold structure is also an important factor affecting the spinning forming process. The matching opening position of the lower mold ejector and the lower mold is the key. If the matching position is selected improperly, it is easy to cause the lower mold ejector to be difficult to return, resulting in the spinning blank Deformation occurs at the mating position.
4.2 Total deformation
The definition of total spinning deformation: the percentage of the original casting billet wall thickness and spinning rough wall thickness difference to the original casting billet wall thickness. The determination of the total deformation directly affects the streamline structure of the material and the mechanical properties of the metal. Under certain conditions, the greater the total deformation, the more obvious the streamline structure of the metal fiber, and the better the mechanical properties. These are pictures of the streamline structure of the metal with a total deformation of 60% and 70%.
To formulate a reasonable spinning process, the total amount of spinning I must be considered, mainly from the aspects of spinning pass thinning rate and spinning deformation defects.
4.3 Optimization of process parameters In addition to the above design, the selection of spinning process parameters has an important impact on the casting spinning process. From the spinning wheel
Form angle, pass thinning rate and other aspects are also elaborated. In order to obtain a good forming state, the selection of the feed rate of the rotary wheel should consider factors such as the wall thickness reduction rate, the thickness of the blank, the diameter of the rotary wheel and the fillet radius. If the feed rate is too high, it is easy to cause the metal in front of the rotary wheel to accumulate, and even cause cracking during spinning; while the feed rate is too small, the inner diameter will expand due to elastic deformation, and the material will be sandwiched.
Therefore, the principle of selecting the feed rate of the spinning wheel is to choose a larger one if possible. The feed rate for thinning and spinning of aluminum alloy wheels is selected in the range of 0.5~3mm/r. The commonly used feed rate is 0.5~1.5mm/ro. The forming angle of the wheel is a very important process parameter. The larger the bump, the higher the bulge, which causes the non-steady flow of metal. Aluminum and its alloys are more prone to bulge, so the forming angle cannot be large. However, if the forming angle is too small, the contact area between the rotary wheel and the blank will increase, and the spinning pressure will increase accordingly, which will have an adverse effect, causing excessive metal accumulation at the front of the rotary wheel, causing metal instability or stress Too large causes breakage. Therefore, the forming angle is generally 20. ~30. Select within the range.
After the total thinning rate (total deformation) is determined, according to the process conditions and process dimensional accuracy requirements, the thinning and spinning is performed in several passes, and the thinning of the pass decreases from large to small. The thinning rate of the spinning pass has an effect on the expansion and contraction of the inner diameter of the workpiece and the accuracy. If the thinning rate of the pass is too large, the flow of the workpiece material will be unstable and accumulate, and the surface is prone to peeling. Too small will cause uneven deformation of the workpiece thickness and insufficient deformation of the inner surface of the workpiece. Usually the pass thinning rate is selected between 15%-50%, and the best thinning rate is 25%-30%.
4.4 The simulation and optimization of casting spinning 2127, the hot spinning forming of aluminum alloy wheel cast blanks is a complex deformation process integrating geometric, physical and boundary conditions with triple nonlinearity. With the progress and development of science and technology, higher requirements are put forward for the research of spinning forming. As a material forming technology with an extremely complex forming mechanism, the spinning forming process has obvious effects on the forming process. Which process parameters have a greater impact on the spinning forming, how to adjust the process parameters to predict the processing effect, and how the existing materials are adaptable to the spinning forming process are all problems that need to be solved urgently in the actual application of the spinning forming process. If you rely solely on test methods to study the spinning process of the wheel hub, it may cause the disadvantages of high cost, long research period, and many random interference factors in the test process. Using only theoretical analysis methods, it is often difficult to quickly and accurately solve various problems in production. The wide application of numerical simulation technology can provide advanced analysis methods for the formulation and optimization of spinning process. A finite element model of the hot spinning process of A356 alloy wheel casting billet was established. Numerical simulation analysis was carried out for the influence of the 212 technical parameters such as the blank opening angle and the trajectory of the spinning wheel, and the optimization design of _-12 technical parameters was realized, which can be used for guidance Actual production shortens product development time.
5. Conclusion This article introduces the production process and principle of aluminum alloy wheel casting spinning process, and analyzes the factors that affect the casting spinning process. The development of aluminum alloy wheel casting and spinning technology is still in its infancy in China. At present, there are few researches on the hot spinning technology of casting aluminum alloy. In order to promote the wide application and development of aluminum alloy wheel casting and spinning process, the hot spinning deformation performance of cast aluminum alloy, the deformation mechanism and flow behavior of metal during hot spinning, the numerical simulation of hot spinning process, parameter optimization and heat treatment process, etc. A lot of in-depth and systematic research needs to be done.
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