In Laser-MAG hybrid welding, there are two welding heat sources, laser and MAG arc, which can form an effective molten pool when used as a heat source alone, but the characteristics of the molten pool are different: the characteristics of the laser welding molten pool are "deep and narrow ", the opening area is small and the depth is large, which is not conducive to the formation of the weld seam; the characteristics of the MAG arc welding molten pool are "shallow and wide", the opening area is large, and the depth is small, which is conducive to the formation of the weld seam and has a strong bridging ability. In the laser-MAG hybrid welding process, two heat sources act on the base metal at the same time, and there is mutual influence between the two heat sources, and there is also mutual influence between the two molten pools, which will eventually form a new composite molten pool. The composite molten pool has both the "large depth" of the laser molten pool and the "large area" of the arc molten pool. Filled with welding wire, and the type of welding wire can be selected, so you can select the appropriate welding wire to add to the welding process according to the performance defects of the base material itself, so as to improve the crack resistance, fatigue resistance and corrosion resistance of the weld on the micro level. , Abrasion resistance, etc. to make purposeful improvements. In addition, in the entire welding process, there are two heat sources acting on the base metal, and the mutual influence between them can increase the penetration depth and achieve the effect of "1+1>2", so the single melting of laser-arc hybrid welding The penetration ability will be significantly improved. Finally, laser-arc hybrid welding can realize multi-pass stack welding, which can realize the welding of large thickness materials, and because of the arc, the fusion ability of the upper and lower weld beads and the side walls is very strong.
Wide range of applications
With the development of laser-arc hybrid welding technology, its application range has become more and more extensive, especially in foreign countries, but there are very few applications in China, and it has broad prospects. The main areas of its application are as follows:
1) Shipbuilding
Among all manufacturing industries, shipbuilding is the biggest beneficiary of laser-arc hybrid welding technology. In order to maintain their advantages in the high value-added shipbuilding industry, some shipyards in Europe have widely adopted laser-arc hybrid welding technology, which greatly improves the welding quality and production efficiency in thick plate welding applications. The typical representative is that the Meyer shipyard in Germany has all adopted the laser-arc hybrid welding method for the welding of ships.
2) Automobile industry
Germany took the lead in applying laser-arc hybrid welding technology to the joint manufacturing of automobile doors, side panels and other components. Scholar Graf T and others reported at the International Forum on Automobile Welding "Application of Laser Hybrid Welding on Volkswagen and Audi Automobiles [C ]" It’s introduced that there are 66 welds on the front door of the Volkswagen Phaeton, with a total length of 4.98m, of which 48 are laser-arc composite welds; the total composite welding length of the body frame of the Audi A8 sedan reaches 4.5m away.
New energy vehicles are developing vigorously. The core of its power is the power battery. In order to reduce the overall vehicle weight, the power battery trays are generally made of aluminum alloy. The trays are assembled and welded, and each tray has dozens of welds. Moreover, the welding seam has high requirements for strength and welding efficiency. Traditional arc welding and conventional laser welding are difficult to meet the requirements, and laser-arc hybrid welding is a very suitable connection method.
3) Petrochemical industry
According to the research of the laser-MAG arc hybrid welding process of the petroleum transportation pipeline, it is found that after welding and using the laser as the heat source alone, the laser-arc hybrid welding can increase the penetration depth by 20%, the welding process is more stable, and there is a small amount of spatter. The seam is well formed, has a good melting width ratio, and has no welding defects such as undercut and unfusion. After welding, the pores are controlled within a certain range by X-ray inspection, which does not affect the quality of the welded joint and meets the engineering requirements.
Laser-MIG hybrid welding is used to weld oil tanks, and the welding penetration is greatly improved due to the addition of laser, so that single-sided welding can be performed, avoiding the inconvenience caused by double-sided welding. Not only has the quality of welding seams been improved, but it has also made a huge breakthrough in improving welding efficiency and production capacity. At present, laser-arc hybrid welding has been widely used in the German oil tank manufacturing industry.
4) Aerospace industry
In the aerospace field, laser-MIG/MAG arc hybrid welding technology has also begun to be used in the welding of medium and thick plates and high-strength steels, achieving 7mm thick 3CrMnSiA non-preheating laser-MAG arc hybrid welding, which greatly reduces the labor intensity and Improved welding production efficiency
