Application of laser welding process in automobile industry
This article describes the application of various laser welding processes in automobile manufacturing.
As a new type of advanced welding technology, laser welding technology plays an important role in the manufacture of many metal products. Among them, the automobile industry uses many metal parts, so it is necessary to connect metal workpieces many times in the production process. The application of laser welding machine is an important technical means to achieve high-quality development of the automotive industry. Compared with traditional automobile body welding technology, laser welding has the advantages of high energy density, fast welding speed, small welding deformation and good flexibility. This article describes the application of various laser welding processes in automobile manufacturing.
Laser deep penetration welding process
Laser deep penetration welding means that when the laser power density reaches a certain level, the surface of the material is vaporized to form a keyhole, the metal vapor pressure in the hole and the static pressure and surface tension of the surrounding liquid reach a dynamic balance, and the laser can be irradiated to the hole through the keyhole. At the bottom, a continuous weld is formed with the movement of the laser beam. There is no need to add auxiliary flux or filler in the welding process of laser deep penetration welding, and the material of the workpiece itself is completely used for welding.
The weld seam obtained by laser deep penetration welding is generally smooth and straight, with small deformation, which is conducive to improving the manufacturing accuracy of the automobile body; the tensile strength of the weld seam is high, which ensures the welding quality of the automobile body; the welding speed is fast, which is beneficial to improve the welding production efficiency.
In automobile body welding, the laser deep penetration welding process can meet the welding needs of body assembly welding and tailor welding. In body assembly welding, it is mainly used for the welding of body roof, side walls, doors and other areas. In body welding, it is mainly used for welding steel plates with different strengths, different thicknesses and different coatings.
Laser wire filler welding process
Laser wire filler welding is a process method in which a specific welding wire is pre-filled in the welding seam or the welding wire is fed simultaneously during the laser welding process to form a welded joint. It is equivalent to inputting approximately homogeneous wire material into the weld pool while laser deep penetration welding.
Compared with laser deep penetration welding, laser wire filler welding has two advantages in automobile body welding. First, it can greatly improve the tolerance of the assembly gap between the auto body parts to be welded, and solve the problem that laser deep penetration welding requires too much groove gap; the second is that the microstructure distribution of the weld area can be improved by using welding wires with different component contents, and then the weld performance can be regulated.
In the process of automobile body manufacturing, the laser wire filler welding process is mainly used in the welding of body aluminum alloy and steel parts. Especially in the welding process of aluminum alloy parts of automobile body, the surface tension of the molten pool is small, which easily leads to the collapse of the molten pool, and the laser wire filler welding process can solve the problem of molten pool collapse to a large extent through the melting of the welding wire during the laser welding process.
Laser brazing process
Laser brazing uses a laser as a heat source. After focusing, the laser beam is irradiated on the surface of the welding wire to melt the welding wire. The molten welding wire drips and fills between the workpieces to be welded, and metallurgical effects such as dissolution and diffusion occur between the solder and the workpiece. Make the workpiece to achieve the effect of connection.
Unlike the laser wire filler welding process, the laser brazing process only melts the wire and not the workpiece to be welded. Laser brazing has good weld stability, but the resulting weld has low tensile strength.
In the process of automobile body welding, the laser brazing process mainly welds the body parts that do not require high joint strength, such as welding between the top cover and side panel of the body, welding between the upper and lower parts of the trunk lid.
Laser arc hybrid welding process
Laser-arc hybrid welding is a hybrid welding process that uses two heat sources, laser and arc, to simultaneously act on the surface of the workpiece to be welded, so that the workpiece is melted and solidified to form a weld.
Laser-arc hybrid welding combines the advantages of laser welding and arc welding. First, under the action of dual heat sources, the welding speed can be increased, the heat input is reduced, and the deformation of the weld seam is small, maintaining the characteristics of laser welding; second It has better bridging ability and greater tolerance for assembly gaps; third, the solidification speed of the molten pool is slower, which is conducive to eliminating welding defects such as pores and cracks, and is conducive to improving the structure and performance of the heat-affected zone; It can weld materials with high reflectivity and high thermal conductivity, and the range of application materials is wider.
In the automobile body manufacturing process, the laser-arc hybrid welding process is mainly used in the welding of the aluminum alloy components of the automobile body and the junction of dissimilar metals of aluminum alloy and steel, mainly for welding parts with large assembly gaps, such as the welding of part of the car door. This is because the assembly gap can exert the bridging performance of laser-arc hybrid welding.
In addition to the above common laser welding processes, with the improvement of the automobile manufacturing industry's requirements for body welding efficiency and the increasing demand for welding of dissimilar materials faced by automobile lightweight manufacturing, laser spot welding, laser swing welding, multi-beam laser welding And the application of laser flight welding and other processes in automobile body welding has attracted attention. As a new welding method, laser welding process will continue to innovate and bring more favorable development to the automotive industry.
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