Introduction to Laser-Arc Hybrid Welding Technology
Laser-arc hybrid welding, first proposed by Steen in the late 1970s and gradually developed to maturity, is a high-quality, efficient new welding technology. Laser-arc hybrid welding combines the energy of two heat sources, laser welding and arc welding, in a specific manner to generate a single molten weld pool. This interaction achieves high-quality, efficient welding of materials and is currently a major research area in global welding technology.
Laser-arc hybrid welding is not simply a superposition of laser and arc heat sources. During the welding process, the two heat sources interact with each other, resulting in a "1 + 1 > 2" synergistic effect and welding results. In arc welding, due to the divergent nature of the arc energy distribution, the actual energy required for material melting is relatively low. The guiding effect of the laser on the arc improves the arc's melting efficiency. In laser welding, the molten metal absorbs laser energy at a higher rate than solid metal, and the arc's preheating of the molten pool also effectively increases the material's absorption efficiency. Therefore, the absorption and conversion rates of a composite heat source are superior to those of a single heat source.
Based on the dominant heat source, hybrid welding can be divided into two categories: one is laser-enhanced arc hybrid welding, in which arc energy plays the primary role. The laser power is too low to form a keyhole. The laser's "hot spot" on the workpiece is used to draw the arc, reducing resistance to arc ignition and preventing arc root drift, thus achieving high-speed and stable welding. The other is arc-assisted laser welding, in which the laser plays the primary role. Arc preheating of the workpiece and plasma interaction between the arc and the laser heat source are typically used to enhance bridging, improve welding process stability, and increase welding efficiency. Currently, arc-assisted laser welding is the mainstream of hybrid welding research.
Compared to traditional welding methods, laser-arc hybrid welding has the following advantages: high welding speed and penetration, good bridging performance, low assembly precision, and excellent process stability. Therefore, it is widely used and researched. Laser-arc hybrid welding can weld a variety of metals and alloys, including high-strength steel, highly reflective materials, and reactive metals. Nowadays, laser-arc hybrid welding technology is increasingly widely used in various industrial fields, and can play its unique advantages in the fields of pipeline construction, shipbuilding, automobile rails, aerospace, etc.
Application of laser-arc hybrid welding
- Transportation manufacturing field
In the automotive industry, Audi of Germany successfully used laser-MIG hybrid welding technology to produce the all-aluminum structure "Audi A8" sedan; Mitsubishi Heavy Industries of Japan used coaxial laser-MIG hybrid welding technology for welding complex structure car bodies in 2003. TWI of the United Kingdom and BIAS of Germany started the development of laser-MIG hybrid welding technology for aluminum alloys for high-speed trains in 2008 and 2009 respectively. Japan built a laser-MIG hybrid welding production line in 2008 for welding aluminum alloy bodies of high-speed trains. In recent years, my country has applied laser-arc hybrid welding to the welding of 600 km maglev train bodies, subway sleepers, and high-speed rail bodies.
- Engineering machinery field
In 2012, Harbin Welding Research Institute first realized the laser-twin-wire MAG composite welding of high-strength steel boom of large-tonnage all-terrain crane. In recent years, Xuzhou Engineering Machinery Group Co., Ltd., Sany Heavy Industry Co., Ltd. and others have adopted laser-arc composite welding, which has stably and efficiently achieved single-sided welding and double-sided forming of the main weld of the boom. The tensile and impact properties of the joints meet the relevant engineering application standards.
- Shipbuilding engineering field
In 2002, Meyer Shipyard established the first laser composite welding production line for welding hull decks. KVAERNER Shipyard in Finland and FINCANTIERI Shipyard in Italy are typical shipyards that apply composite welding. The US Navy applies laser-MIG arc composite welding technology to the welding of thick steel plates for ships. In China, the Yantai Raffles Shipyard uses the laser arc hybrid welding equipment of Harbin Welding Research Institute.
