Metal forming is a method that utilizes the plastic rheological properties or basic physical properties of a material to cause changes in the geometric shape and texture of the material.
Metal forming technology is currently the basic manufacturing technology of the defense industry such as aviation, aerospace, and weapons. At the same time, it is also a technical support for the civil industry such as automobiles, instrumentation, and machinery industries.
With the development trend of industrial components integration, precision, and complexity, the demand for advanced metal forming technology is more pressing; metal forming technology is constantly being reformed and enriched under the joint promotion of engineering requirements and basic research.
Superplastic forming technology
Application in automotive manufacturing
Superplastic forming is a metal forming technique widely used in the aerospace field. It is a method that utilizes the superplasticity of a material to obtain a uniform large deformation at a certain temperature and strain rate to achieve part forming. It is a relatively advanced metal at present. Sheet metal lightweight manufacturing technology.
In addition to aerospace, the automotive industry is currently facing the pressure of energy conservation and emission reduction due to environmental pressures. In order to effectively reduce fuel consumption, lightweight structural manufacturing technology has become one of the key issues in the development of the automotive industry. The use of lightweight materials such as aluminum alloys and magnesium alloys to replace steel plates is an important method for weight reduction of automobile bodies.
At present, industrial aluminum alloy automobile body structure parts and cover parts are mostly cold stamped and formed. Compared with steel plates, aluminum alloys have larger rebound and lower plasticity at room temperature, which makes the use of cold stamping methods to form complex shapes of aluminum alloy cars. Forming the cover is difficult. However, the aluminum alloy is a typical superplastic material. In the superplastic state, even if the deformation amount reaches several hundred percent, the formed part will not rebound.
Therefore, in recent years, the superplastic forming of aluminum alloy automotive panels has become a research hotspot and has been applied in the industrial field. At the 8th International Conference on Superplasticity, automobile companies in Japan and Switzerland and other countries introduced large-scale aluminum alloy coverings produced by superplastic forming methods, which opened up prospects for the application of superplastic forming in the automotive industry, as shown in Figure 1. Shown is a large aluminum alloy car cover.
Superplastic forming has the advantages of no rebound, simple mold structure, single process, and low equipment load. However, the price of fine-grained superplastic aluminum alloy sheet is much higher than that of ordinary sheet, which results in high cost of superplastic forming cover. Limit its large-scale application.
The emerging industries for the application of high pressure forming technology are automotive, aerospace, aviation, bicycles and pipelines.
Among them, the automobile is the most widely used industry in the internal high pressure forming technology. The types of parts applied in the automobile include:
1 chassis components, including the subframe, rear axle, longitudinal beams and bumpers;
2 body components, including instruments Pan beams, radiator brackets, seat frames, roof rails and roof beams, etc. ;
3 Engines and drive systems, including manifolds and exhaust fittings, camshafts and drive shafts, etc.;
4 Steering and suspension systems, including control arms and Steering levers and so on.
The car exhaust manifold (one out of two) tube physical map developed and produced
by Xingdiyuan Machinery
Applications on aircraft include hollow frame beams, hollow crankshafts and special-shaped pipe fittings on the engine.
Applications in aerospace applications include rocket power system piping joints and profiled section intakes.
In the past decade, the internal high pressure forming technology has been widely used in the automotive industry. The demand for vehicles and other transportation tools to reduce quality and reduce costs has also contributed to the continuous improvement of the internal high pressure forming technology and its rapid development, and its development trend:
(1) Ultra-high pressure forming. At present, the maximum pressure of the supercharger used in industrial production is generally 400 MPa. In order to adapt to more complex structural shapes and precision, larger wall thickness and high strength materials (ultra-high strength steels, titanium alloys, high-temperature alloys, etc.), higher internal pressures are required and will develop to 600 MPa or even 1000 MPa.
The engine cooling pipe real picture developed and produced
by Xingdiyuan Machinery
Advanced Hydraulic (Inner High Pressure) Forming Process
Once formed engine cold tube
Finite Element Analysis of Intermediate Cold Pipe Hydraulic (Inner High Pressure) Forming
(2) New forming process. Welded pipe high pressure forming, the welding of different thickness or different material pipe into a whole, and then use the internal high pressure forming a structural part, can further reduce the structural quality; use two different diameters of the tapered pipe, manufacturing special structural parts, such as When the car crashes, it absorbs the energy structure; the double-pipe high-pressure forming manufactures the double-decker exhaust pipe of the car to improve the three-way catalytic and purification effect of the car exhaust; and the profile tube with the initial cross-sectional shape is non-circular is used as a preform to form the design requirements. Parts; external pressure forming and internal and external pressure combined forming; internal high pressure forming and connecting process, several pipes or pre-formed pipes are placed in the internal high pressure forming mold, and processed into one part by forming and connecting process, further Reduce the number of parts and improve the integrity of components.
(3) Ultra-high strength steel forming. With the further improvement of the automobile's demand for lightweight structures, the strength of the steel used on the vehicle body is getting higher and lower, and the material shaping is reduced. For example, the strength of the steel is increased from 250 MPa to 1000 MPa, and the plasticity is reduced from 45% to 12%. The decrease in plasticity of the material leads to serious cracking and increases the difficulty of forming. It is necessary to conduct in-depth research on bending, preforming, internal pressure forming process, wall thickness distribution, and lubrication.
(4) hot internal pressure forming. In order to solve the problem of low room temperature plasticity and difficult forming of high-performance aluminum alloys, magnesium alloys and other light alloy materials, the use of heated and pressurized media to form special-shaped cross-section parts is an important direction for the development of internal high pressure forming. At present, the temperature of heat-resistant oil as the medium can reach 300°C and the pressure can reach 100MPa, which can fully meet the needs of aluminum alloy and magnesium alloy pipe forming. The main problem of hot internal pressure forming is long forming time and low efficiency. For titanium alloys, it needs to be formed at a temperature above 600°C. The purpose of the heat-resistant oil is not reached at this temperature. Using gas as a forming medium is a good solution.
Metal forming technology is a key basic manufacturing technology. With the continuous improvement of component manufacturing requirements in the industrial field and the wide application of new materials, the demand for advanced metal forming technology is more urgent.
On the one hand, the metal forming technology profession needs to be further innovated and enriched under the demand traction, adapting to the development trends in different industrial fields;
on the other hand, through the basic research, incubating advanced forming technology and stimulating the application of new materials and new structures for engineering applications. The design provides greater freedom, and it attaches great importance to the promotion and application of metal forming technology in the civil industry and market expansion, enhances the ability to create value, and creates technical and economic benefits.
Part of the text is taken from
"Application Status and Development Potential
of Advanced Metal Forming Technology in Civil Industry"
Author: AVIC Beijing Aeronautical Manufacturing Technology Research Institute of Industrial
Han siu-quan, Du Lihua, Shao Jie
Edited by Xingdiyuan Machinery
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