Magnesium alloy workpiece pre-weld surface laser cleaning method

Abstract

The invention discloses a magnesium alloy workpiece pre-weld surface laser cleaning method which comprises the following steps of assembly of a laser cleaning device, position adjustment and laser cleaning. In the step of the laser cleaning, (1) the laser power of a pulse fiber laser is set at 100-200W, the pulse width is set at 20-30ns and the pulse frequency is set at 20-30KHz, a one-dimension galvanometer is adopted for scanning with the scanning speed being 3000-4000mm / s, and the laser beam scanning line width is adjusted to 30mm; (2) the movement rate of a manipulator is set, so as to allow the migration rate of laser linear light spots on the surface of a workpiece to be 10mm / s; (3) switches on a smoke filtering system and a compressed air supply pipeline are opened; and (4) the pulse fiber laser is started for laser cleaning, and repeated cleaning is carried out based on the cleaning effect. With the adoption of the mode, the magnesium alloy workpiece pre-weld surface laser cleaning method adopts the laser cleaning mode, so that the cleaning efficiency and the cleaning quality of a magnesium alloy pre-weld surface oxidation film are improved, no backing material is damaged in a cleaning process, and the environment of a cleaning working field is improved.

Description

technical field [0001] The invention relates to the technical field of laser cleaning, in particular to a laser cleaning method for the surface of a magnesium alloy workpiece before welding. Background technique [0002] In order to prevent corrosion, magnesium alloys need to be oxidized. At present, more chromium film-forming methods are used, so that the magnesium alloy workpiece is immersed in the treatment solution mainly composed of chromic acid or dichromate, so that a layer of magnesium oxide, chromium oxide or chromate is formed on the surface to fill it. The thickness of the oxide film is usually 0.5-3μm. This layer of oxide film is very dense and can effectively protect the substrate from corrosion, but it is extremely unfavorable to the welding of magnesium alloy workpieces. [0003] The melting point of magnesium alloy is low, while the melting point of oxide film is very high. During welding, the oxide film will hinder the fluidity of the molten pool, easily ca...

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Problems solved by technology

[0007] Chemical and mechanical methods can effectively remove the oxide film on the surface of magnesium alloys, but the chemical method has many procedures and low efficiency, and the gas generated is harmful to the human body and the environment; mechanical scraping will cause damage to the surface of the magnesium alloy, resulting in surface Stress will affect the welding quality, and the powder produced by scraping will also cause harm to human health

[0008] The above two types of cleaning methods have their own problems to varying degrees, which limit their large-scale application in the field of magnesium alloy surface cleaning. Today, with increasingly stringent environmental protection requirements, it is urgent to find a green and efficient cleaning method.

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