A friction stir welding device and method for the longitudinal seam of the bottom circular ring of a large-diameter launch vehicle

Abstract

The invention discloses a friction stir welding device and method for a circular-ring longitudinal seam at the bottom of a box of a large-diameter carrier rocket. The friction stir welding device comprises a rotating table, a moving backing plate device, N split moulds and N external pressing systems. The rotating table is a circular-ring-shaped table, the rotating table is evenly divided into N fan-shaped areas, each fan-shaped area is provided with one split mould, each mould is provided with one external pressing system, and the moving backing plate device is installed in the inner circulararea of the rotating table and can move radially along the inner circular area of the rotating table. According to the method applying the friction stir welding device for welding, the secondary assembly of circular ring assemblies can be effectively avoided, the problems of poor fitting and low assembly quality of the product inner molded surface and a backing plate caused by the secondary assembly are solved, the assembly quality before repair welding can be guaranteed, 100% qualified repair welding is achieved, the welding quality of a longitudinal seam at the bottom of an extra-large-diameter box of a heavy carrier rocket is guaranteed, and the product manufacturing accuracy and efficiency are improved.

Description

technical field [0001] The invention relates to a device and method for friction stir welding of circular longitudinal seams at the bottom of a launch vehicle with a large diameter, and belongs to the technical field of welding at the bottom of a launch vehicle. The large diameter refers to a storage tank with a diameter of not less than 7.5m. Background technique [0002] Friction stir welding (FSW) is a solid-phase welding process invented by the British Welding Institute in 1991. During the welding process, the stirring head converts mechanical energy into internal energy and transfers it to the material to be welded. Due to the low welding heat input, the welded The metal only undergoes plastic flow but does not melt, and does not produce pores, thermal cracks, over-burning and joint softening. It is suitable for the connection of light alloy metals such as aluminum and magnesium. At present, this process has been widely used in the fields of aviation, shipbuilding and a...

AI Technical Summary

Problems solved by technology

The diameter of the bottom of the heavy-duty launch vehicle reaches Φ7.5m or more, which is a super-large and overweight product. If the bottom of the box is lifted off the membrane tire after welding, it is very difficult to return the bottom of the box to the membrane tire due to excessive defects that require repair welding. Welding deformation and shrinkage. On the one hand, it is impossible to ensure that the second assembly height of the melon petals is consistent with the first assembly. On the other hand, after reassembly, the bottom of the box is buckled on the membrane tire, blocking the welding backing plate, and it is impossible to measure and guarantee 4~6m by effective means. The inner surface of the long melon petal longitudinal seam and the outer surface of the backing plate can be fitted without gaps

If repair welding is carried out under the condition of poor assembly quality, the quality of repair welding cannot be guaranteed. In severe cases, the stirring head may be stuck on the backing plate, resulting in product scrapping

Images