The energy model was founded to calculate the critical power of keyhole formation by using the limit principle in CW （ continuous wave ） Nd： YAG laser deep penetration welding process. The model was validated by ex...The energy model was founded to calculate the critical power of keyhole formation by using the limit principle in CW （ continuous wave ） Nd： YAG laser deep penetration welding process. The model was validated by experiments. The results show that ＇.there are two errors between the calculated critical power of keyhole formation and that of experiments ： one is that the calculated results is less than those of experiments, which is caused by not considering the energy loss by heat conduction in the model of keyhole formation. The other is that there is 0. 9 mm error between the axis of the calculated curve of critical power with location of laser focus and that of experimental curve, which is induced by the excursion of laser focus in laser deep penetration welding. At last, the two errors were revised according to the analyses of the errors.展开更多
Deep penetration laser welding temperature field of 5A06 aluminum alloy canister structure was simulated using the surface-body combination heat source model by ANSYS, which was made up of Gauss surface heat source mo...Deep penetration laser welding temperature field of 5A06 aluminum alloy canister structure was simulated using the surface-body combination heat source model by ANSYS, which was made up of Gauss surface heat source model and Gauss revolved body heat source model. Convection, radiation and conduction were all con,sidereal during the simulation process. The thermal cycle curves of the points both on the shell outer surface and in the seam thickness direction were calculated. Simulated results agreed well with the experiment results. It concluded that the surface-body combination heat source model was fit for the temperature field simulation of deep penetration laser welding of the aluminum alloy canister structure. This method was proved to be an efficient way to predict the shape and dimension of welded joint for deep penetration laser welding of the aluminum alloy canister structure.展开更多
In laser non penetration deep penetration welding process, welding material will vaporize, metal vapor and ambient gas will produce a higher degree ionization, which forms plasma of high concentration. In the case of...In laser non penetration deep penetration welding process, welding material will vaporize, metal vapor and ambient gas will produce a higher degree ionization, which forms plasma of high concentration. In the case of forming a small hole, plasma will eject from the hole, and form acoustic emission (AE) signals. Because AE information has many advantages such as non contact measuring, fast response, and high ratio of signal to noise, it can be used as a monitor variable for in process control. By studying AE information, information of welding pool and small hole can be obtained. According to characteristic of AE information, this paper reveals the correlation between welding parameters and AE signals, and provides a good base for further quality control.展开更多
The laser welding residual stresses in an aluminum alloy thick-wall cylinder is investigated by means of nonlinear finite element method. The article has simulated the residual stresses distribution of the longitudina...The laser welding residual stresses in an aluminum alloy thick-wall cylinder is investigated by means of nonlinear finite element method. The article has simulated the residual stresses distribution of the longitudinal weld. The result shows that the temperature is high and temperature gradients are large in the very narrow zone under the laser beam. And the axial residual stress shows the alternate tensile stress and compressive stress. Also the axial residual stress is tensile stress along weld line and the stress peak value appears in the middle of the welded seam. What is more, it is symmetric distribution in the distance from the beginning and the last step welding 20 mm. Good agreements are found between calculated results and measured results indicating the validity of the assumptions made for the development of the model.展开更多
文摘The energy model was founded to calculate the critical power of keyhole formation by using the limit principle in CW （ continuous wave ） Nd： YAG laser deep penetration welding process. The model was validated by experiments. The results show that ＇.there are two errors between the calculated critical power of keyhole formation and that of experiments ： one is that the calculated results is less than those of experiments, which is caused by not considering the energy loss by heat conduction in the model of keyhole formation. The other is that there is 0. 9 mm error between the axis of the calculated curve of critical power with location of laser focus and that of experimental curve, which is induced by the excursion of laser focus in laser deep penetration welding. At last, the two errors were revised according to the analyses of the errors.
基金supported by the Education Department Science and Technology Development Foundation of Shanxi Province, China(200671)Repatriate and Study Abroad Foundation of Shanxi Province, China (200680)
文摘Deep penetration laser welding temperature field of 5A06 aluminum alloy canister structure was simulated using the surface-body combination heat source model by ANSYS, which was made up of Gauss surface heat source model and Gauss revolved body heat source model. Convection, radiation and conduction were all con,sidereal during the simulation process. The thermal cycle curves of the points both on the shell outer surface and in the seam thickness direction were calculated. Simulated results agreed well with the experiment results. It concluded that the surface-body combination heat source model was fit for the temperature field simulation of deep penetration laser welding of the aluminum alloy canister structure. This method was proved to be an efficient way to predict the shape and dimension of welded joint for deep penetration laser welding of the aluminum alloy canister structure.
文摘In laser non penetration deep penetration welding process, welding material will vaporize, metal vapor and ambient gas will produce a higher degree ionization, which forms plasma of high concentration. In the case of forming a small hole, plasma will eject from the hole, and form acoustic emission (AE) signals. Because AE information has many advantages such as non contact measuring, fast response, and high ratio of signal to noise, it can be used as a monitor variable for in process control. By studying AE information, information of welding pool and small hole can be obtained. According to characteristic of AE information, this paper reveals the correlation between welding parameters and AE signals, and provides a good base for further quality control.
文摘The laser welding residual stresses in an aluminum alloy thick-wall cylinder is investigated by means of nonlinear finite element method. The article has simulated the residual stresses distribution of the longitudinal weld. The result shows that the temperature is high and temperature gradients are large in the very narrow zone under the laser beam. And the axial residual stress shows the alternate tensile stress and compressive stress. Also the axial residual stress is tensile stress along weld line and the stress peak value appears in the middle of the welded seam. What is more, it is symmetric distribution in the distance from the beginning and the last step welding 20 mm. Good agreements are found between calculated results and measured results indicating the validity of the assumptions made for the development of the model.
