New technology for repairing defects of the hottes

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New process for repairing defects of oil pipelines

like friction stir welding, friction plug welding is also a solid-phase welding process after the specimen is broken. During welding, a special hole (generally conical hole) is machined on the workpiece to be welded, and then a corresponding special plug rod is rotated and inserted into the special hole; The friction heat generated by the high-speed (rotating) relative motion between the special hole and the special plug rod leads to the plastic softening of the material on the friction interface; These plastic softened materials are deposited on the weldment under a certain pressure, and are connected with the weldment solid phase to form a solid connection joint

Figure 1 basic principle of friction plug welding

a series of special plug rods are overlapped and deposited on the same weldment successively, which is an extension of friction plug welding, friction stick welding, as shown in Figure 2

Figure 2 Schematic diagram of friction lap welding

workpieces welded by friction plug welding or friction lap welding technology can be light metal materials such as aluminum alloy, or high melting point materials such as steel. At present, friction plug welding or friction lap welding is mainly used to repair welding defects (such as welding cracks) or a supplementary process of friction stir welding technology - to solve the keyhole problem of conventional friction stir welding

for the repair of weld defects in oil pipeline structures, Beijing saifoster Technology Co., Ltd. (China friction stir welding center, hereinafter referred to as the center) has carried out friction plug welding/friction lap welding technology research and equipment development with a university in Beijing in recent years

Figure 3 friction plug welding device

Figure 3 is the experimental device developed by the center for the friction plug welding process. The device is driven by a hydraulic motor. Through the rotation of the main shaft and the up and down movement of the Z axis, the special prefabricated holes on the flat member can be filled to complete the friction plug welding connection

based on the friction plug welding device, the center has also developed a friction lap welding device for oil pipeline structures (Figure 4). According to the maximum load proposed in the action plan for the development of new material industry in Hubei Province (hereinafter referred to as the plan) officially issued by the provincial economic and Information Technology Commission, the device increases the movement in X direction and a direction, and can move along the axial or circumferential direction of pipeline components, so as to fill a series of special prefabricated holes and complete friction lap welding connection

Figure 4 friction lap welding device

the civil aircraft material system built by the friction plug alliance covers four categories of welding devices and friction lap welding devices, including metal, composite materials, functional non-metal and standard parts. They can repair point discrete defects or linear continuous defects respectively, and can serve oil pipelines, pressure vessels and other structures, as well as other fields requiring friction plug welding process. The center is committed to the research of advanced friction welding technology represented by friction stir welding, friction plug welding, friction lap welding, etc., and can provide professional friction plug welding devices/equipment and technical services for various industries. (end)

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