With the rapid development of science and technology, laser welding is widely used in the industrial market, especially automobile production, precision manufacturing, agricultural machinery production, etc. Many customers have doubts about “how strong is laser welding” when purchasing laser welding machines. Let’s take a closer look.
Metal laser welding
Metal laser welding is an efficient and precise welding method that uses high-energy-density laser beams as heat sources. Lazer welding can be achieved using continuous or pulsed laser beams. The principles of laser welding can be divided into heat conduction welding and laser deep penetration welding.
Thermal conduction laser welding
The spot power density of laser thermal conduction welding on the surface of the workpiece is low, generally less than 105W/cm2. The laser delivers energy to the surface of the welding workpiece, causing the metal surface to heat to between the melting point and boiling point.
The surface of the metal material converts the absorbed light energy into heat energy, causing the metal surface temperature to continuously increase and melt, and then transfers the heat energy to the interior of the metal through thermal conduction, so that the melting area gradually expands, and after cooling, a solder joint or weld is formed. This This welding principle is similar to tungsten arc welding (TIG) and is called thermal conduction welding.
Laser deep penetration welding
When the laser power density acting on the metal surface is greater than 105W/cm2, the high-power laser beam acts on the surface of the metal material to cause local melting and form a “small hole”. The laser beam penetrates deep into the melt through the “small hole”. Inside the pool, the metal melts in front of the small hole, and the molten metal flows around the small hole to the rear, where it solidifies again to form a weld.
How about laser welding strength?
Laser welding technology was early used in the field of military tank manufacturing. Welding products in national defense have extremely high standards and are extremely demanding on welding environments and processes, so lasers can provide welding strength and welding grades that are far higher than traditional technologies.
With the improvement of laser welding technology, Volkswagen Group, which is good at body manufacturing hard technology, has applied laser welding technology to the field of automobile welding. This has revolutionized the welding grade and strength of automobile structures and parts. It is enough to illustrate the advantages of laser welding sheet metal.
Laser welding features:
- When using a laser welding machine to connect workpieces, there is almost no connection gap between the workpieces to be welded. At the same time, the welding aspect ratio is large, the post-welding deformation is small, the heat-affected zone is small, and the precision is high.
- The welding device is simple and flexible, can be welded at room temperature or under special conditions, and has low requirements on the welding environment.
- The laser welding machine has considerable penetration depth and high power density, and can weld refractory materials, such as titanium alloy, No. 45 steel, etc.
Effect of welding speed on laser weld strength
As long as the power of the laser remains consistent, the laser welding speed will directly affect the strength of the welding. When performing deep penetration welding, the faster the speed, the smaller the weld. Because the speed is fast, the hot melt gas cannot volatilize in time. During the welding Gas is easily generated in the gaps, so it cannot be welded quickly.
When the welding speed remains constant, the intensity of laser welding will produce a critical zone, and the increase of laser power will increase the intensity of laser welding. This is because increasing the power will increase the penetration and lead to the increase of laser welding intensity.