Friction stir spot welding
2020-01-18 13:07:55
Currently, two different FSSW technologies are reported in published materials. The first method is the friction stir spot welding J invented by Mazda Motor Corporation of Japan in 1993. The basic principle is shown in Figure 1. Introduction With the increasingly severe global resources and environmental protection issues, the lightweight design of vehicles has become the development direction of automotive, aerospace and other manufacturing fields. On the one hand, aluminum alloy is used instead of traditional steel materials, and on the other hand, high-efficiency new technology is used to improve product reliability and reduce product weight. Aluminum alloy is the main manufacturing material for vehicles. The main connection method is welding and riveting. In the European automobile body production, the commonly used connection technology is the YAG laser welding method. In Japan, the resistance spot welding method is commonly used in the manufacture of automobile bodies. In the manufacturing process of the carrier rocket tank, a large number of resistance spot welding and riveting techniques are applied, and aviation The manufacturing process of the aircraft requires extensive use of riveting technology. Resistance spot welding has high production efficiency and good operational flexibility, but it also has many limitations, mainly in:
a. The welding process needs to provide a large current and consumes a large amount of energy;
b. The oxide film on the surface of the aluminum alloy causes the electrode life to be significantly shortened;
C. Due to the large current of the welding, the workpiece will have obvious thermal deformation, and the defects in the weld and the quality of the solder joint are unstable, and the joint quality is poor;
d. There is spatter during the welding process, and the spot welding work environment is poor. Riveting is a commonly used joining technology in aluminum alloy components, but the riveting technology will increase the weight of the aluminum alloy components on the one hand, and generate a lot of noise in the riveting process on the other hand, and the production environment is bad. In addition, the riveting technology needs to be Pre-opening on the aluminum alloy component increases production costs. Therefore, research and development of new spot welding technology for aluminum alloys replaces traditional resistance spot welding and riveting technology, which is of great significance for expanding the application of aluminum alloys in the automotive industry, promoting the development of lightweight vehicles and improving aviation and space carrying capacity.
Friction Stir Spot Welding (FSSW) is an innovative welding technology newly developed on the basis of "linear" friction stir welding. FSSW can form spot welded lap joints, and its weld appearance is similar to that of resistance spot welding which is usually applied to aluminum alloy components, so it has high application value and research significance.
Basic Principles of Friction Stir Welding At present, two different FSSW techniques are reported in published materials. The first method is the friction stir spot welding J invented by Mazda Motor Corporation of Japan in 1993. The basic principle is shown in Figure 1. This kind of friction stir spot welding is also called “stirring and spot welding with exit hole†technology. The welding equipment used is similar to ordinary friction stir welding equipment. The specific welding process can be divided into three stages:
a. Pressing process: the stirring head rotates continuously, and is inserted into the connected workpiece by applying the upsetting pressure. Under the action of pressure, friction heat is generated between the workpiece and the stirring head to soften the surrounding material, and the stirring head is further pressed into the workpiece;
b. Connection process: The mixing head is completely embedded in the workpiece, maintaining the pressure of the mixing head and contacting the shoulder to the surface of the workpiece, and continuing to rotate for a certain period of time:
C. Retraction process: After the connection is completed, the agitator head exits from the workpiece, leaving a typical exit recess in the center of the spot weld. The second method is the friction stir spot welding invented by the German GKSS Research Center in 1999. The special mixing head is used to precisely control the relative movement of the components of the mixing head, and the mixing head is filled in the welding process while the mixing head is retracted. The exit hole formed is flat, and the spot weld welded by the method is flat, and there is no concave hole in the center of the solder joint. The stirrer spot welding stir head is mainly composed of three parts, namely the innermost probe, the middle layer sleeve and the outermost jacket. Wherein, the jacket is fixed during welding without rotation, and the sleeve of the intermediate layer and the probe of the innermost layer both rotate and move in the axial direction during welding.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
a. The welding process needs to provide a large current and consumes a large amount of energy;
b. The oxide film on the surface of the aluminum alloy causes the electrode life to be significantly shortened;
C. Due to the large current of the welding, the workpiece will have obvious thermal deformation, and the defects in the weld and the quality of the solder joint are unstable, and the joint quality is poor;
d. There is spatter during the welding process, and the spot welding work environment is poor. Riveting is a commonly used joining technology in aluminum alloy components, but the riveting technology will increase the weight of the aluminum alloy components on the one hand, and generate a lot of noise in the riveting process on the other hand, and the production environment is bad. In addition, the riveting technology needs to be Pre-opening on the aluminum alloy component increases production costs. Therefore, research and development of new spot welding technology for aluminum alloys replaces traditional resistance spot welding and riveting technology, which is of great significance for expanding the application of aluminum alloys in the automotive industry, promoting the development of lightweight vehicles and improving aviation and space carrying capacity.
Friction Stir Spot Welding (FSSW) is an innovative welding technology newly developed on the basis of "linear" friction stir welding. FSSW can form spot welded lap joints, and its weld appearance is similar to that of resistance spot welding which is usually applied to aluminum alloy components, so it has high application value and research significance.
Basic Principles of Friction Stir Welding At present, two different FSSW techniques are reported in published materials. The first method is the friction stir spot welding J invented by Mazda Motor Corporation of Japan in 1993. The basic principle is shown in Figure 1. This kind of friction stir spot welding is also called “stirring and spot welding with exit hole†technology. The welding equipment used is similar to ordinary friction stir welding equipment. The specific welding process can be divided into three stages:
a. Pressing process: the stirring head rotates continuously, and is inserted into the connected workpiece by applying the upsetting pressure. Under the action of pressure, friction heat is generated between the workpiece and the stirring head to soften the surrounding material, and the stirring head is further pressed into the workpiece;
b. Connection process: The mixing head is completely embedded in the workpiece, maintaining the pressure of the mixing head and contacting the shoulder to the surface of the workpiece, and continuing to rotate for a certain period of time:
C. Retraction process: After the connection is completed, the agitator head exits from the workpiece, leaving a typical exit recess in the center of the spot weld. The second method is the friction stir spot welding invented by the German GKSS Research Center in 1999. The special mixing head is used to precisely control the relative movement of the components of the mixing head, and the mixing head is filled in the welding process while the mixing head is retracted. The exit hole formed is flat, and the spot weld welded by the method is flat, and there is no concave hole in the center of the solder joint. The stirrer spot welding stir head is mainly composed of three parts, namely the innermost probe, the middle layer sleeve and the outermost jacket. Wherein, the jacket is fixed during welding without rotation, and the sleeve of the intermediate layer and the probe of the innermost layer both rotate and move in the axial direction during welding.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
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