Numerical Simulation of the laser welding
The model takes into consideration thermophysical and metallurgical properties of theremelting steel, laser beam parameters and boundary conditions of the process. As a resultof heating the material, in the area of laser beam operation a weld pool is being created,whose shape and size depends on convection caused by the Marangoni force. The directionof the liquid stream depends on the temperature gradient on the surface and on the chemicalcomposition as well. The model created allows to predict the weld pool shape depending onmaterial properties, beam parameters, and boundary conditions of the sample.
Numerical Simulation on Stress Fields of Lasers Braze Fusion Welding
The assembled tube was made of beryllium tube and tungsten tube, and was produced by over fitting. The residual stresses in the assembled tube were very comprehensive after lasers braze fusion welding, not only including the welding residual stresses, but also the initial stresses from over fitting. Both of the dimension and strength were affected by the complex residual stress distribution in the assembled tube. MSC.MARC software was used to simulate the stress fields during lasers braze fusion welding of the assembled tube. The stress fields during lasers braze fusion welding and the residual stresses after welding have been obtained, and the effect of over fitting on welding residual stress of the assembled tube have also been studied. The residual stresses at outer surface of the assembled tube have been measured by the X-ray diffraction method. A comparison of the residual stresses by finite element method (FEM) to that by experiment indicates an identical stress change trend and thus validates the FEM model.
Finite Difference Modeling on the Temperature Field of Substrate in Friction Surfacing
Friction surfacing is an advanced process of great potential, especially in the field of repair and reclamation of worn and damaged components. As a kind of thermal processing technology, the temperature profile and changes of the substrate in friction surfacing are important factors to get coatings of high quality. In this paper, the temperature field of the substrate during the process is simulated by finite difference method. The results are consistent with experiments, reappearing the temperature change of the substrate during friction surfacing, allowing further study on figuration and quality of coatings.