Laser welding process of automobile cover parts

Laser welding process Especially in the field of automobile industry has been paid attention to and widely used, in which the automobile cover is one of the five categories of laser welding. It can reduce body weight, improve body assembly precision, increase body stiffness, and reduce stamping and assembly cost in the process of automobile body manufacturing. Laser self – melting laminated welding technology of automobile coverings When reaches a certain power density range (106 ~ 107 W/cm2) of laser beam to the surface of a material, material to absorb light energy is converted into heat energy, melt materials are heated to boil, produce a large number of metal vapor, the steam escape surface under the reaction of the molten metal liquid to exclude, form, as a continuation of the laser irradiation, The pit penetrates deeper, and when the laser stops irradiating, the liquid around the pit flows back, and the two workpieces are welded together after cooling and solidification. Factors affecting laser welding 1, laser power There is a laser energy density threshold value in laser welding, below which the workpiece only melts on the surface and the melting depth is very shallow, that is, the welding is carried out in a stable heat conduction type. Once this value is reached or exceeded, the plasma will be generated, which indicates that the steady deep fusion welding is carried out and the penetration depth will be greatly improved. If the laser power is lower than this threshold value and the laser power density is small, there will be insufficient penetration or even unstable welding process. 2. Welding speed The welding speed has a great influence on the penetration depth. Increasing the welding speed will make the penetration shallow, but too low the welding speed will lead to excessive melting of materials and welding through of workpiece. Therefore, there is a suitable range of welding speed for a particular material with a certain laser power and a certain thickness, and the maximum penetration depth can be obtained at the corresponding speed value. 3, the amount of defocus In order to maintain sufficient power density, the focal point location is critical. In each plane away from the laser focus, the power density distribution is relatively uniform. There are two ways of defocusing: positive defocusing and negative defocusing. If the focal plane is located above the workpiece, it is positive defocus; otherwise, it is negative defocus. The change of defocus directly affects the width and depth of the weld. 4. Protective gas In laser welding, inert gases are often used to protect the molten pool, but in most applications, gases such as argon, nitrogen and helium are often used to protect the workpiece from oxidation during welding and to blow away the plasma.铜焊丝,Copper Welding Rods,铝焊丝,aluminium welding wire,镍焊条,Nickel electrode,药皮焊条,Flux Coated Brazing Welding Rods