Laser welding is a high efficiency and precision welding method using high energy density laser beam as heat source. Laser welding is one of the important aspects of laser material processing technology. In the 1970s, it was mainly used for welding thin-walled materials and low-speed welding. The welding process belongs to heat conduction type, that is, the surface heat is heated by laser radiation, and the surface heat is guided to internal diffusion through heat transfer. By controlling the parameters of laser pulse width, energy, peak power and repetition frequency, the workpiece is melted to form a specific molten pool. Because of its unique advantages, it has been successfully used in precision welding of micro and small parts. Laser welding can be realized by continuous or pulsed laser beam. The principle of laser welding can be divided into heat conduction welding and laser deep penetration welding. When the power density is less than 104 ~ 105 w / cm2, it is heat conduction welding; When the power density is greater than 105 ~ 107 w / cm2, the metal surface is concave into "holes" under the action of heating, forming deep penetration welding, which has the characteristics of fast welding speed and large depth width ratio.
China's laser welding is at the world's advanced level. It has the technology and ability to use laser to form complex titanium alloy components with an area of more than 12 square meters, and has invested in the prototype and product manufacturing of several domestic aviation research projects. In October 2013, Chinese welding experts won the Brooke award, the highest academic award in the welding field, and China's laser welding level has been affirmed by the world.