Laser Deep Penetration Welding Process Simulation Technology Research

Laser deep penetration welding as a high-energy beam welding, is widelyadopted by manufacturing industry,because of narrow weld, high welding speed,small deformation of the work piece and the heat-affected zone, high precisionetc. The laser deep penetration laser welding only generates small holes in thewelding process. For the strong interaction with laser beam, the metalexperiences melting, vaporization and the gas flow push aside the liquid in avery short period. The rapid reaction process makes the laser deep penetrationwelding temperature field well distributed. For the rapidly changingcharacteristics of temperature and stress field, it is really difficult to takeexperimental method to measure temperature and stress field distribution oflaser deep penetration welding. However, the rapid development of computertechnology provides more convenient conditions for the numerical simulation oflaser welding, so numerical simulation of laser welding based on finite elementanalysis software is attracting more and more attention.The heat source model is the basis of welding simulation because accuracyof simulation has a strong relationship with the heat source model used. Toovercome the shortcoming of existing heat source model, comprehensiveconsideration of the characteristics of energy distribution by CO2laser is takenfor the actual physical process of laser deep penetration welding. This paperestablished Cone-Gauss body heat source model, which is based on this heatsource model simulating the laser point welding, laser flat butt welding, andcurve of the corrugated plate weld laser welding.Firstly, on the basis of the actual physical process of laser deep penetration,composited with cone function and Gaussian heat source distribution function,the cone Gauss body heat source model that based on laser deep penetration isgiven. And on the basis of theory of welding heat conductance, using analyticmethod, the weld width and depth corresponding different heat source powerand beam radius is obtained by calculation. According to different weldingparameters corresponding to the weld width and depth, regression analysis is used to determine the basic parameters of the heat source model of the cone.And the heat source model parameters are expressed by welding parameters.Then, by the numerical simulation of laser spot welding, we get a result inaccordance with related papers; therefore the three-dimensional moving heatsource model which established in this paper can be used to simulate the poolforming process of laser deep penetration welding is confirmed. Differentwelding parameters simulated the temperature and stress field of laser plate buttwelding is used. The experiments confirmed that the simulation results are inaccordance with experimental results. The welding speed and welding powerimpact on the shape of the metal pool, analysis results are discussed and proveconsistent with the experimental results. Further evidence is provided for thefeasibility of Cone-Gauss body heat source model used in simulating of laser flatbutt welding.Finally, on the basis of the simple modification of the cone Gaussian heatsource model, first the temperature field of curve of the corrugated plate weldlaser welding is simulated. And according to the simulation results, thetemperature field changes characteristics of this welding manner are brieflydiscussed. In the end the change rule of the temperature peak value is given.Simulation results show that, the Cone-Gauss body heat source modelestablished in this paper could be well used in the simulation of laser pointwelding, laser flat butt welding, and curve of the corrugated plate weld laserwelding. It proves that the heat source model established in this paper hascertain significance to physical production.