Welding Deformation Control Of Main Combustor Flame Tube Of UAV

As an important aviation engine hot section, fl ame tube is welded together by sixty four primary holes, thirty two blenders, two ignition spark plug s, eight mounting brackets, sixteen head swirl mounts and other parts, of which the main material is GH3536. By using MSC.Marc, thermal-mechanical coupled numerical simulation of electron beam welding process was carried out to analyze the flatness and the circumference of the top and bottom cycle of the thin welded structure, to ensure smooth implementation of the follow-up process.Combined with electron beam welding parameters, by using cylindrical heat source, the nonlinear properties of the thermal physics and mechanical parameters of high-temperature alloy GH3536 are tested, those parameters are necessary inputs in simulation modeling. Welding schemes such as single blender welding, four blenders welding, four blenders and eight primary holes welding was carried out, respectively. By comparison the deformation of the different welding sequences, it is founded that, for a single blender, welding deformati on mainly concentrated in the vicinity of the weld zone, and there is a slight change of circumference for the inner hole of the blender after welding. The residual stress approaches yield limit near the weld seam, which declines rapidly with the distance to the weld center increases. The deformation for the two welding sequences of the four neighboring blenders varied obviously, the skip welding deformation control was much better than continuous intensive welding. The welding sequence has more impact on deformation, while residual stress distribution has no obvious difference under the above two welding sequences. The welding deformation for the continuous welding in the circumference is the worst choice for deformation control, while skip welding with 180°-phase skip is much better.It is can be concluded that, the more retardation for welding positions among two sequential order welding position in axial symmetry, the better for the deformation control of the structure with 32 blenders and 64 primary holes. Meanwhile, jig is also important for welding deformation control of thin-walled structure, the original process should increase to eight-point clamping fixture, in order to improve the quality of weldment.