AC Magnetic Field Assisted Laser Deep Penetration Welding Method for Reducing Porosity in Aluminum Alloy Weld

Abstract

An AC magnetic field-assisted laser deep penetration welding method for reducing pores in aluminum alloy welds. After the bottom of the butt joint of the sample to be welded is suspended, an AC electromagnetic field is preset below it, and the laser welding process is set above the sample. The laser welding working head and the AC electromagnetic field under the sample remain static, and the laser beam is focused on the upper surface of the aluminum alloy, and the magnetic field always covers the entire molten pool area until the laser deep penetration welding is completed. The method reduces the porosity of the weld seam to the greatest extent while ensuring that the penetration depth of the weld seam remains unchanged, that is, increases the bearing area of ​​the weld seam. In addition, the irregular fluctuations caused by the existence of pores on the original weld surface are also suppressed, and the improvement of this surface shape also contributes to the improvement of joint strength.

Description

technical field [0001] The invention relates to a technology in the field of laser welding, in particular to an AC magnetic field-assisted laser deep penetration welding method for reducing pores in aluminum alloy welds. Background technique [0002] At present, submerged arc welding and gas metal shielded welding are mainly used for the connection of medium and thick aluminum alloys of large structural parts in the fields of ships, pipelines, and wind energy equipment. However, these technologies have low welding efficiency and large heat input. Easy to produce large deformation. As a flexible welding method that can be automated, laser welding has the advantages of high energy density, good flexibility and small deformation, and is an excellent choice for welding medium and thick plates. [0003] During the laser deep penetration welding process, the material at the laser incident position evaporates violently, and the recoil pressure of the metal vapor squeezes the molte...

AI Technical Summary

Problems solved by technology

For laser deep penetration welding of aluminum alloys with low surface tension and viscosity, the problem of small hole pores is more serious, resulting in technical problems of reduced joint strength. An AC magnetic field assisted laser deep penetration welding method to reduce weld pores in aluminum alloys is proposed. , on the premise of maintaining a large penetration depth, there is no need to preheat before welding or change the welding process parameters to suppress the porosity, just adjust the appropriate magnetic field parameters to avoid excessive magnetic field disturbances from aggravating the instability of welding small holes, using alternating The Lorentz force generated by the magnetic field in the molten pool drives the bubbles upward to escape, so as to suppress or even completely eliminate the small pores

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