Research On Laser Welding Characteristics Of GH3128/06Cr19Ni10

For the fabrication of water wall of afterburner in some type aircraft, the laserpenetration welding technology of dissimilar metals in T-shape joints is analyzed.Through systematic experiments of laser welding of dissimilar alloys of GH3128and06Cr19Ni10, the influences of laser welding parameters on welding shaping and defectsare studied and the optimal process parameters are obtained; the formation mechanismof welding defects is also analyzed. What’s more, the numerical simulation model ofthis welded structure is established using finite element method. The reason of crack isanalyzed through the result of finite element analysis, at the same time, the residualstress field of different welding parameters after welding is also analyzed.Firstly, the welding procedure test was carried out, the continuous laser weldingwas proved to be suitable for the welding of the two metals in this paper by comparingthe cross-section and the surface of the weld bead of continuous laser welding and pulselaser welding. Therefore, the welding procedure test of continuous laser welding wasmainly studied. The influence of welding parameter on penetration depth, bead widthand width of joint face was analyzed. The optimized welding parameter was obtained bycomprehensive consideration of appearance of weld and weld defect. The optimizedwelding intervals are as follows: laser power1000W, welding speed1.2~2.0m/min.What’s more, the weld cracks were analyzed, weld cracks fell into three types byposition of formation and characteristic. The cause and regulation of weld cracksformation of every type of cracks were analyzed in detail.Secondly, the thermo-mechanical coupling analysis was carried out by Marc whichwas the most famous finite element software. The hybrid heat source model which wascomposed by a double-ellipsoid heat source model and a Gaussian cylindrical one wasused to simulate the welding process. The temperature-dependent material propertieswere used, the influence of radiation, convection and fixture on welding process wasconsidered. The veracity of the finite element model was confirmed by the comparisonof the bead cross-section and thermal cycling curve.At last, the changing regulation of the stress during welding and the residue stressof weld workpiece were studied by using the simulation result. During the cooling process, the stress of the HAZ of GH3128next to the joint face was very large, and thestress got larger with the progress of the cooling process. After the finishing of the weldprocess, the residue stress of the edge of the joint face was very lager too. What’s more,the multiple weld structure was also analyzed by finite element method, by comparisonthe residue stress and deformation of different welding sequence, the regulation thatwelding sequence had no effect to the deformation and residue stress was found.