What is laser welding?
Laser welding belongs to the most modern welding methods, it is a competition for advanced welding processes, among others electron welding. The welding process is characterized by very high efficiency and the ability to combine the most diverse shapes in all welding positions, which increases the efficiency of production processes.
The laser welding process consists in fusing the area of contact of the joined objects with heat obtained as a result of the addition of a concentrated coherent beam of very high power density to this area.
How can you weld with a laser?
Welding can be done by:
The very high power densities of the laser beam ensure that the linear energies of the welding are very small that are required to melt the joint, and the SWC and the melting zone are very narrow.
The joint deformation is so small that no mechanical machining is required after welding. The laser is a light amplification by means of forced radiation emission.
What are the basic parameters of laser welding?
Parameters of laser welding:
Basic terms related to laser welding
In welding, two types of lasers are most commonly used:
The laser beam passing from the laser to the workpiece through the iris system of mirrors and optical elements is focused in the welding area. The beam of laser light falling on the surface of the metal undergoes an intensive reflection depending on the type of metal and its surface condition. The effectiveness of laser welding depends mainly on the absorption of energy of the laser beam over the surface of the workpiece. Therefore, an important problem when welding is the proper preparation of the surface by matting or blackening. Welds made with a continuous emission laser do not differ from welds made with an electron beam, whereas the impulse laser welds consist of a set of partially overlapping point welds corresponding to individual impulses. When welding thin sheets <3 [mm] from low carbon steel due to high welding speeds and short weld metal residence time in oxidation temperatures, it is possible to dispense with the cover
In the case of welding reactive materials, it is necessary to use a gas shield with an inert gas of the weld pool as well as the ridge of the connector. Laser welding can take place with or without the addition of a binder, in one pass or in multiple layers.
Laser welding allows combining at comparable or higher quality all metals, which are joined by means of electron welding.
What gases do we use in laser welding?
2. Ar (Argon)
3. N (Nitrogen)
4. CO₂ (Carbon dioxide)
What are the main advantages of laser welding?
Laser welding is used for welding a very large range of materials such as structural steels, alloy steels, duplex, Cr / Ni, high-strength low-alloy steels, carbon steels, refractory metals, chemically active metals, aluminium, titanium, nickel and magnesium.
The basic problem that should be taken into account when choosing laser technologies are metallurgical processes which are characterized by local very strong and short-term heating> 10,000 ° C / sec, and then very fast cooling. These phenomena often cause obstructions and cracks.
Therefore, in the case of welding materials that are prone to the formation of quenching structures and porosity, it is necessary to provide for such treatments as pre-heating or annealing after welding.
Laser welding is a high-throughput method in high-volume, automated or robotic production, and especially for joining small, thin-walled elements, where the advantages of this method are being used more and more fully.