In High Power Solid-state Laser Sheet Metal Welding Technology Research

In laser welding process,because the focesed laser own high energy density(105～10W/cm2or the higher),it can form the weld with a lager ratio which penetration depth to penetration width.Additionally the welding line has many advantages,such as small heat affect Zone、small welding stress、small deformation perfect appearance and so on.Laser welding has been more and more popular in the contemporary weld field.Recent years,with the mature and industrialization of the fiber laser technology and the CO2laser technology, people become less and less emphasis on the high-power solid-state laser.With the development of science and technology, I consider the high-power solid-state laser will be taken seriously again.Laser welding technology with high-power solid-state laser will also become one of the important aspect on the reserch.304stainless steel (0Cr19Ni9) and steel(Q235) are the most widely uesd in modern industrial applicationgs of engineering materials, which have good weldability.IN the paper, the high-power solid-state laser tailor-welded experiment was carried out on the different thickness304stainless steel and steel(Q235) by single variable experimental method. The influence of the parameters including welding speed and the defocusing distance on the quality and surface morphology of the welding line were investigated,and the experimental results were analyzed combined with the theory of the laser deep penetration welding. Meanwhile, the tensile property of the test piece was measured. Through all of this, we finally find out the best laser welding process parameters that can be uesed to actual production for the infferent thickness304stainless steel and steel(Q235).The experimental result shows that setting the welding parameters(such as laser power, welding speed and defocusing distance, ect.) of304stainless steel and steel(Q235) plate, the weld strength can exceed the yield strength of the base metal, and some can even reach the tensile strength of the base metal.It can provide reliable welding process parameters for industrial applications. When protective gas Ar is40L/min, the laser power is2.5kW and the welding speed is relatively reasonable.The focus position on the plate surface below0.5mm of the single-sided butt welding of metal plate will weld better, and the focus position on the plate surface more than0.5mm of the double-sided butt welding of metal plate is better.The paper also introduces a new kind of laser welding equipment--LW2512CNC laser welding system.The LW2512CNC laser welding system uses the light guide fiber to spread the beam, finally the CNC machine installe laser welding head to complete the flat two-dimensional welding. The system consists of a3kW high-power solid-state laser, the control system structrue, LW2512CNC laser welding machine, etc.