The 19th Shenzhen International Machinery Manufacturing Industry Exhibition came to a successful conclusion on April 4th at the Shenzhen Convention and Exhibition Center. The conference brought together more than 1,200 manufacturing top companies from more than 20 countries and regions around the world, as well as the latest products and cutting-edge technology solutions, presenting the future of China's manufacturing industry in a multi-dimensional and all-round way. During the conference, two heavyweight seminars were held. Many industry executives and exhibitors discussed and exchanged the latest industry and technology application trends.
As a leading enterprise in intelligent manufacturing in China, Harbin Smart was invited to participate in the “Automobile Lightweight Era – Robotics and Application Development” forum. The company's special expert Mr. Wan Long took “Application and Challenge of Robot Friction Stir Welding on New Energy Vehicles”. "The most revolutionary friction stir welding technology in welding technology is introduced. The friction stir welding technology has been comprehensively introduced in terms of the development trend of new energy vehicles, the principle of friction stir welding technology, technology and application scenarios.
Introduction to friction stir welding
Friction stir welding is a method of using the heat generated by the mutual movement of the workpiece end faces and rubbing each other to make the end portion reach the thermoplastic state, and then rapidly forging and completing the welding.
Friction welding can easily connect the same or different materials, including metals, some metal-based composites, ceramics and plastics. The friction welding method has been applied in the manufacturing industry for more than 40 years. Due to its high productivity and good quality, it has been widely used in engineering applications. However, the welding object is mainly rotary parts, although other forms of friction welding technology have emerged to overcome the problem. Welding workpiece geometry limits or increase productivity, such as phase friction welding, radial friction welding, linear friction welding, etc., but practical applications are few. Recently, frictional surfacing has also occurred to form a special surface layer on the workpiece.
Friction stir welding characteristics
No other welding consumables, such as welding rods, welding wire, flux and shielding gas, are required during the welding process. The only consumption is the welding mixing head.
The temperature at the time of friction stir welding is relatively low, so the residual stress or deformation of the structure after welding is also much smaller than that of the fusion weld. Especially when the Al alloy thin plate is melted and welded, the out-of-plane deformation of the structure is very obvious. Whether using the non-deformation welding technology or the post-weld cold and hot calibration technology, it is very troublesome, and the manufacturing cost of the structure is increased.
Friction stir welding has been successfully applied in the connection of non-ferrous metals, but due to the limitations of the welding method, it is limited to the structurally simple components, such as the welding of straight structures or cylindrical structures, and the workpieces are required during the welding process. Have good support or village mats. In principle, friction stir welding can be used for a variety of position welding, such as flat welding, vertical welding, overhead welding and down welding; various types of welded joints can be completed, such as butt joints, gussets and lap joints, and even thickness variations. The connection to multi-layer materials can also be used to weld dissimilar metal materials.
Friction stir welding is a solid phase welding method that has little environmental pollution before and during welding. Pre-weld workpieces do not require strict surface cleaning preparation requirements. Friction and agitation during welding can remove oxide film on the surface of the weldment. Smoke and splash are also generated during the welding process, and the noise is low. Since the friction stir welding only rotates and moves by the welding head, the welding of the entire weld is gradually realized, so that energy is saved more than fusion welding or even conventional friction welding.
Friction stir welding problems
The welded workpiece must be rigidly fixed and the bottom surface should have a bottom plate;
When the welding end of the stirring probe is raised, a weld hole is formed at the end of the weld, and it is difficult to repair the weld;
Tool design, process parameters and mechanical performance data are available only in a limited range of alloys;
In some cases, if corrosion performance, residual stress and deformation are to be considered in a special field, the performance needs to be further improved before it can be practically applied;
When the board is single-passed, the welding speed is not very high;
The wear of the mixing head is consumed too quickly.
Development status of friction stir welding
The application of friction stir welding on aluminum alloys is more and more extensive, and research is getting deeper and deeper. It not only involves the welding of various materials of the same kind, but also the welding of a wide range of dissimilar aluminum alloys. The welding thickness of aluminum alloy ranges from lmm to 75mm. A lot of research has been done on the corrosion performance, mechanical properties and microstructure of aluminum alloy welded joints. Friction stir welding is widely used in 6061Al/2024Al, 2024Al/Ag, 2024Al/Cu, 6061AI/cu, and even 6061AI+20%Al2O3/cast aluminum alloy A339+10% SiC.
In 2002, China Aviation Industry Group-Beijing Aviation Manufacturing Engineering Research Institute and British Welding Research Institute jointly signed a cooperation agreement on patents on friction stir welding patent technology, technology research and development and market development. China’s first specialization The friction stir welding technology licensing company - China Friction Stir Welding Center, Beijing Safest Technology Co., Ltd. was established, marking the official opening of the friction stir welding technology research and engineering application in the Chinese market.
As a new method of multi-disciplinary intersection, friction stir welding can develop longitudinal seam welding, circumferential seam welding, keyless hole welding, variable section welding, self-supporting double-sided welding, space 3D curve welding, friction stir spot welding, backfilling Various types of joining processing methods and techniques such as spot welding, friction stir welding surface modification treatment, friction stir welding superplastic material processing.
After nearly ten years of rapid development, Safford has successfully developed more than 60 sets of friction stir welding equipment, applying friction stir welding technology to China's aviation, aerospace, shipbuilding, train, automotive, electronics, electric power and other industrial fields. It has created considerable social and economic benefits and provided perfect technical solutions for metal materials such as aluminum, magnesium, copper, titanium and steel. It provides domestic and foreign users with processing of friction stir welding industrial products of different types and different uses, including : aerospace tubular structural parts, aerospace thin-wall structural parts, ship wide-ribbed slabs, high-speed train body structure, large thickness radar panels, automobile hubs, container profile siding, various structural radiators and heat sinks.
At the seminar, Mr. Wan Long described how to combine friction stir welding technology with the robot industry.
With the steady development of the traditional automobile industry and the spurt development of new energy vehicles, lightweighting is a major goal pursued by automobile manufacturers. Therefore, most manufacturers choose aluminum alloy materials with a density of 2.70 kg/cm3 for lightweight body. However, there are some problems with the connection of aluminum alloy materials.
Friction Stir Welding—The revolutionary welding technology breakthrough in the field of welding for nearly 30 years has effectively solved the problems in the connection of aluminum alloy materials, and the advantages are obvious. Compared with arc welding, the strength of the friction stir welded joint can reach 80%-120% of the base metal, the fatigue performance is 80%-95% of the base metal, with little or no post-weld deformation, no porosity defects, element burning loss. Hot crack or consumable problem.
Among the many friction stir welding equipments, the combination of robot and friction stir welding has obvious advantages. The robot friction stir welding can significantly improve the welding quality by providing a constant pressure control mode; it can realize multi-station simultaneous welding, which can improve the welding efficiency by 2-3 times; the high automation integration can improve the mass production capacity. It has been applied to the welding of new energy vehicle battery cold plate, motor controller housing, motor housing, Pack box, special-shaped cover plate and other components.
The development of friction stir welding technology has made considerable progress in the development of FSW equipment and process technology.
In the future, Harbin Smart and its 51robot platform will focus on the development of new smart vehicle solutions and suppliers of new energy vehicles and core components, further enhancing the company's market competitiveness in the field of automotive intelligent manufacturing suppliers.
source：未知