Tungsten pole inert gas protection electric arc welding preheating stirring friction welding composite method

Abstract

A combined welding method consisting of TIGarc welding for preheating and stirring friction welding features that the welding gun of TIG arc welding is fixed to a slide rod connected to the stirring head of stirring friction welding, and they are arranged in the front of the seam to be welded. After the TIG arc welding is applied for preheating, the stirring friction welding is conducted under pressing, so resulting in high speed and quality.

Description

technical field [0001] The invention relates to a welding method used in the field of welding technology, in particular to a tungsten inert gas shielded arc welding preheating-friction stir welding composite method. Background technique [0002] There are a series of difficulties in welding aluminum alloy, magnesium alloy and some other non-ferrous metals, mainly manifested in: strong oxidation ability; high thermal conductivity, easy to produce pores, cracks, large deformation and other defects during welding; alloy elements are easy to burn loss etc. Due to welding heating, the performance of the metal to be welded is reduced, which greatly limits its application in structures such as aircraft and ships. [0003] After searching the literature of the prior art, it was found that "AZ31 magnesium alloy friction stir welding joint nugget area" published by Zhang Hua et al. Forming process and influencing factors[J]”, which introduces the method of friction stir welding: tha...

AI Technical Summary

Problems solved by technology

Its disadvantages are: the back of the workpiece joint needs to have a baffle or fixture sufficient to withstand the pressure of the stirring head; the welding speed is low; The effect will make the grains become narrow and long; the uneven grain size distribution of welded joints is also related to the distribution of frictional heat during welding

When the pressure of the stirring head is small and the amount of the stirring head is not pressed enough, the frictional heat generation will be insufficient, so that enough plastic fluid material cannot be produced, the material flow is not sufficient, and it cannot rotate and move around the stirring head well, and cannot completely Filling the gap in the lower layer will easily form holes at the bottom of the weld, resulting in incomplete penetration

In addition, when welding some special grades of alloy materials, the welding speed is relatively slow; friction stir welding requires a large welding pressure (more problems will occur during robot welding), which also limits the application of this new connection technology in manufacturing. wide application of

In the process of friction stir welding, with the intensification of the friction between the stirring head and the workpiece or the prolongation of the friction time, the temperature of the stirring head rises faster, which reduces the high-temperature strength of the stirring head, resulting in the breakage of the stirring needle of the stirring head and a serious decline in welding quality.