Laser-electric arc compound welding method suitable for high strength aluminum alloy downward welding

Abstract

The invention relates to a laser-electric arc compound welding method suitable for high strength aluminum alloy downward welding. By adopting a compound welding process of combining dipulse variable polarity plasma arc welding with laser welding, high, intermediate and low frequencies of pulse variable polarity plasma arc pulse currents are controllable by means of control: the high frequency pulse frequency is 200-1000 Hz, the low frequency pulse frequency is 1-5 Hz, and the power frequency is 40 Hz; the welding process parameters are as follows: the plasma current is 160-220 A, the electricarc voltage is 21-30 V, the arc height is 5-6 mm, the plasma welding gun angle is 45-60 degrees, and high purity argon protection is carried out; the laser power is 1.5-2.5 kw, the laser defocusing amount is -5-5 mm, and the laser beam is 5-10 degrees inclining to the side of the welding gun; and the electric arc is in front of the laser beam, the separation distance from light to tungsten is 3-6mm, and the welding speed is 480-1040 mm / min. The laser-electric arc compound welding method can reduce weld heat input and improve the welding efficiency.

Description

technical field [0001] The invention belongs to the field of welding technology, and in particular relates to a laser-arc composite welding method suitable for high-strength aluminum alloy flat welding. Background technique [0002] Variable polarity plasma is known as the defect-free welding of light alloys such as aluminum alloys, but due to its low welding efficiency, limited welding position, poor perforation formation in aluminum alloy flat welding, and severe tungsten electrode burning when welding medium and thick plates with high current , and the softening of high-strength aluminum alloy welded joints is more obvious. [0003] Due to the high energy density of the laser, it has a strong deep melting ability. Since the aluminum alloy laser welding has a high reflectivity to light and heat, the high temperature gradient of the laser welding energy leads to serious thermal crack defects, and strict requirements on assembly accuracy. And high-power lasers are expensive...

AI Technical Summary

Problems solved by technology

[0005] However, the existing single-pass laser arc hybrid welding method has the following disadvantages: 1) the penetration ability of the welded plate is relatively weak; Increasing the welding current will lead to high heat input and reduced joint strength; 2) The high-strength aluminum alloy welded joint softens severely, the non-compressed arc is relatively divergent, and the welding heat input is large; 3) The back of the weld is poorly formed, often with insufficient welding, Large fluctuations in height

4) Slag inclusion, pores and cracks tend to be more serious

[0006] The above problems restrict industrial production and application. Therefore, it is necessary to provide a more economical and efficient welding method for the shortcomings of the above-mentioned laser-arc hybrid welding method.

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