Friction stir welding method based on hawk energy and mixed surface nanocrystallization technology

Abstract

The invention provides a friction stir welding method based on a hawk energy and mixed surface nanocrystallization technology. According to the method, firstly, the surface of a base material to be welded is ground and polished; then supersonic particle bombardment surface nanocrystallization treatment is conducted, a nanometer layer with the thickness not lower than 50 micrometers is formed on the surface of the base material to be welded, and the average size of surface nanometer crystals is not greater than 50 nm; surface mechanical rolling is conducted on the surface of the base material to be welded; oil stains on the surface of the base material to be welded are removed with acetone, and then friction stir welding is conducted; trimmings on the upper surface of a joint are shoveled after welding is completed, and a transition zone is polished smoothly; and finally the surface of the welding joint is treated through a hawk energy technology, the surface roughness of the material is reduced to be in the range of 0.01-0.2 micrometers, and the surface microhardness is greater than 300 HV. According to the friction stir welding method, many nanometer layer zones can be formed in the friction stir welding joint, the S-shaped line formation rate caused by the roughness of the welding surface of the base material to be welded is reduced, the surface roughness of the welding joint is improved, and the comprehensive performance of the friction welding joint is improved.

Description

technical field [0001] The invention relates to a friction stir welding method for high-quality welding of metal materials. Background technique [0002] Friction stir welding is a new solid-phase joining technology invented by the British Welding Institute. It can effectively avoid various defects such as pores and cracks caused by traditional fusion welding. It has energy saving and environmental protection, low joining temperature, small residual stress after welding and joint A series of advantages such as high performance can realize high-quality welding of high-strength aluminum alloys (such as 2××× series and 7××× series aluminum alloys) that are traditionally considered unweldable. The schematic diagram of the device is as follows figure 1 . Friction stir welding has received extensive attention since its invention. It is the connection technology with the shortest time span from invention to industrial application in the history of welding technology development in...

AI Technical Summary

Problems solved by technology

[0003] After friction stir welding of metal materials, the weld seam is under the action of high-temperature thermal cycle generated by friction stir, and the strengthening phase is coarsened or melted back, resulting in the heat-mechanically affected zone of the weld seam being the weak link of the welded joint. , tensile strength, corrosion under stress and other aspects need to be improved urgently. At the same time, the surface roughness of the friction stir welded joint is very large, which further affects the comprehensive performance of the welded joint.

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