Research On Controlling Of Welding Distortion And Welding Technology Of Aluminum Alloy Metro End Structure

End structure of metro vehicle chassis is the core component of the whole body structure, which is of huge loading capacity while the loading are always dynamic. The chassis end structure is composed of aluminum alloy thick plate welding structure, and it's manufactured after cutting, bending, welding and other production processes. Due to the dense weld seams, and the complexity of multiple structures, it's difficult to control welding distortion. And that became the core control points of the chassis end structure's welding technology.Firstly, this thesis classifies the welding joint of the chassis end structure, and conducted 5 welding procedure qualification experiments on welding joint under EN15614-2 standard. The result shows that the weld ability of 6000 series of aluminum alloy completely fits the procedure requirement, and it can be used in the welding of the end structure of metro vehicle chassis.Started with structure design, also considering the assemble requirement of chassis, the fitting allowance and the rationality of procedure, this thesis sets the component of every part of the chassis end structure and the whole technical requirements, as well as the drawing about the location of all the check points mentioned in technical requirements.Experiments show that if the end structure of chassis is welded without clamped, the welding deformation would violate both parts and total dimension and shape restriction. After analyzing the cause of the chassis end structure welding distortion, this thesis proposed that by reserving the procedure allowance, making specific tool and using integral-overturn welding clamp combined with positioner can ensure that the deformation of most assembly welding can be controlled. The result shows that the planeness of the corbel has been limited to 0.3mm, the integral symmetry 3mm, the integral planeness 2.5mm and the perpendicularity 2mm. All mounting dimensions meets the requirement of the follow-up joint, the quality of the welding seam also meets the standard.By successfully install 15 metro vehicle chassis end structure, we demonstrate that the welding procedure of chassis end structure discussed in this thesis is both stable and useful. The high quality of the product earns the acceptance of customers, raises the awareness of the company and generates profound advertising effect.