1, the technical feasibility of laser welding

Laser (stimulated emission of light) is the most basic features: color, direction, relevance, these unique properties coupled with the resulting ultra-high brightness, ultra-short pulses and other properties it has been firmly and modern industry together, these qualities are suitable for Welding Electrode. Lasers generally work by laser-generated material to different categories, mainly semiconductors (GaAs, InP, etc.) lasers, solid (Nd: YAG, etc.) laser, gas (CO2, He-Ne, etc.) lasers, liquid (tunable dye, etc.) lasers, chemical lasers, free electron lasers. Gas lasers in which gas or metal vapor as the light particle, it is the most species, the most diverse incentives, the widest distribution area of ​​laser wavelength, easy to implement high-power continuous output, the most widely used class of lasers. Solid-state laser is the laser-generated particles mixed in the solid substrate, its concentration than the gas, therefore the access to relatively large laser energy output, with energy, high peak power, compact, strong and durable. In laser welding of the main shock on the use of these two substances by the laser. Laser welding technology applications in manufacturing increased steadily, from pulse to continuous, from small power to the power, by the thin to thick pieces, from simple to complex shape of the single-slit, laser welding in the continuing evolution has gradually become a mature modern processing technology. Laser welding into a continuous pulse laser welding and laser welding, continuous welding can be divided into heat transfer in welding and deep penetration welding. With the laser output power increases, especially the emergence of high-power CO2 laser, laser deep penetration technology at home and abroad have been developing rapidly, the largest welding aspect ratio has reached 12:1, laser welding materials from the general development of low carbon steel welding galvanized sheet today, aluminum, titanium, copper and ceramic materials, laser welding speed has reached tens of meters per minute, laser welding technology has become more sophisticated, and large number of applications to the production line, in the car welding production line, such as gears, automotive floor and structural parts (including door body) and high-speed welding and has achieved tremendous economic and social benefits.

According to relevant statistics, advanced industrial countries in Europe, 50% -70% of car parts is to use laser processing to complete. Mainly dominated by laser welding and cutting based, laser welding in the automotive industry has become the standard process. Laser welding for body panels can be of different thickness and different coating of coated metal plate welded together, and then stamping, this panel structure made of metal to achieve the most reasonable combination. Laser welding speed of about 4.5m/min, and rarely deformed, eliminating the need for secondary processing. Accelerated the use of laser welding instead of forging parts stamping parts process. Laser welding can reduce the overlap width and some strengthening components, you can also compress the size of their body structural parts. This alone can reduce body weight 56kg. Laser welding for welding roof shell and the frame, drive converter cover weld from the CNC control, the cycle time is about 16 seconds, the actual welding time is only three seconds a day can run continuously for 24 hours. For welding car's gearbox and chassis assembly, laser beam welding speed, easy automation and easy to merge into a flexible manufacturing system, the laser beam to improve the manufacturer's product design into production cycles, reduced product waste rate.
2, laser welding applications in the automotive industry

Using laser welding to the automotive industry can bring enormous economic benefits, such as a large number of spot Aluminum Electrode in car assembly, the two welding head caught in the weld on the edge of the workpiece, the flange width required 16mm, while the welding laser welding is unilateral , only 5mm, the spot of the laser welding, each vehicle can save steel 40kg. Traditional spot welding two pieces of 0.8mm steel plate stamping, the average is 20 points / min, from welding is 25mm, the speed of 0.5m/min, laser welding speed can reach 5m/min more. Laser welding technology, not only reduce costs but also greatly improves production efficiency.

â‘  a different intensity level + low carbon steel alloy (or low-alloy steel + low-alloy high strength steel)
General requirements for the strength of the weld metal or joints welded metal of not less than two kinds of minimum strength, the choice of the strength of deposited metal electrode should be able to ensure the strength of the weld and joint strength of the lower voltage of not less than the strength of base metal, while the weld metal ductility and toughness should not be less than voltage higher strength and ductility performance of the base metal. Therefore, according to the two lower levels of intensity among the selected steel electrode. However, in order to prevent weld cracks, should be a higher intensity level, poor welding of steel to determine the Welding Electrode process, including welding specifications, preheating temperature and post weld heat treatment and so on.
â‘¡ low alloy austenitic stainless steel +
Should be in accordance with the chemical composition of the deposited metal limit values ​​in the selection of electrodes, generally used in higher levels of chromium and nickel, plastic and good crack resistance of austenitic steels Cr25-Ni13-type electrode, in order to avoid brittle hardened tissue caused by cracks. However, poor welding of stainless steel should be determined and the welding process specification.
â‘¢ stainless steel sheet
Should consider the grassroots level, stratified, transition requirements of the welding electrode selection of three different properties. Of the primary (carbon steel or low alloy steel) Aluminum Electrode, choose the appropriate intensity level of the structural steel welding rod; stratified direct contact with corrosive media, should use the corresponding components of austenitic stainless steel electrode. The key is the transition layer (ie, cross-stratified with the primary interface) welding, must take into account the dilution of the matrix material should be used in high chromium and nickel content, good ductility and crack resistance of austenitic steels Cr25-Ni13-type electrode.