Magnesium alloy laser-ultrasonic double-side welding method

Abstract

The invention discloses a magnesium alloy laser-ultrasonic double-side welding method and relates to a double-side welding method. The laser-ultrasonic double-side welding method comprises the following steps: firstly, cleaning and clamping a to-be-welded workpiece, setting the ultrasonic and laser position, further setting related processing parameters to carry out welding; compared with a conventional argon tungsten-arc welding (TIG welding) method, the laser-ultrasonic double-side welding method disclosed by the invention has the advantages that the welding speed is higher, the magnesium alloy welding efficiency is improved, deficiencies like pores, slag inclusion and hot cracks which are easily produced in welding joints, as well as incomplete penetration are reduced, so that the welding joint can meet the using requirements; compared with the one side ultrasonic assisted laser welding method, the laser-ultrasonic double-side welding method disclosed by the invention further has the advantages that the temperature gradient in the molten pool is smaller under the actions of the heat sources, namely laser and ultrasonic, due to the fact that the ultrasonic wave is applied onto the back surface of a welding seam, the welding deformation and the thermal stress produced during the welding process are smaller, the tendency that the welding joint produces hot cracks within a brittle temperature range is effectively reduced, and the mechanical property of the welding seam is further improved.

Description

technical field [0001] The invention relates to a laser-ultrasonic double-sided welding method for a magnesium alloy thin plate, which belongs to the field of material processing engineering. Background technique [0002] As the lightest metal structural material, magnesium alloy is widely used in aerospace, automobile manufacturing, electronic communication, national defense and military fields. With the development of science and technology, magnesium alloys will be more and more widely used in various fields. Therefore, the development of high-efficiency and high-quality connection technology has become one of the key issues that need to be solved urgently. At present, the welding methods of magnesium alloy mainly include: tungsten inert gas shielded welding, melting pole inert gas shielded welding, friction stir welding, laser welding, electron beam welding and so on. [0003] When using traditional arc welding methods (TIG, MIG welding, etc.) to weld magnesium alloys, ...

AI Technical Summary

Problems solved by technology

However, magnesium and other elements are easy to form low melting point eutectic segregation in the grain boundary, which increases the tendency of hot cracks, and welded joints are prone to hot cracks in the brittle temperature range, so hot cracks are still the main problem in laser welding of magnesium alloys ;

[0008] (3) Magnesium alloys have high thermal conductivity. When welding magnesium alloys with high-power heat sources and high welding speeds, it is easy to cause overheating of the weld seam and the metal near the seam area, and the grain growth leads to grain coarsening;

[0010] (5) The surface tension of magnesium alloy is small, and the weld metal is prone to collapse during welding

Patent 200710144908 discloses a method of ultrasonic-assisted laser brazing (melting) welding. The wettability of weld metal has been greatly improved by ultrasonic-assisted welding, but the control of pores and cracks in the weld still needs to be improved in this method

Patent 201310061962 discloses a method of ultrasonic-assisted laser repair, which solves the problem of coarse crystal grains, but this method uses an ultrasonic introduction device to directly introduce ultrasonic waves from the bottom of the workpiece, which reduces the energy utilization rate of ultrasonic waves

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