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Study of Laser Welding Process for 2A16 Aluminum Alloy and Numerical Simulation

Author: LiJianLi
Tutor: ChengJun
School: Xi'an University of Technology
Course: Materials Science and Engineering
Keywords: Aluminum alloy Laser welding Microstructure Temperature field Stress field Numerical Simulation
CLC: TG456.7
Type: Master's thesis
Year: 2009
Downloads: 164
Quote: 0
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Abstract


Aluminum alloy density, high specific strength and high stiffness, flexibility, impact resistance, corrosion resistance, easy shaping and low temperature brittle transition and many other advantages are widely used in a variety of welded structures. The laser welding with high energy density and concentrated heating, welding speed, small thermal damage to the material, weld depth to width ratio large, low residual stress, the joint is the preferred process for welding of high strength aluminum alloy. This paper studies the the 2A16 aluminum laser welding process, the analysis of the main factors affect the welding process stability and weld performance and impact of the law, using ANSYS finite element method for the numerical simulation of aluminum alloy laser welding temperature field and stress field , analysis of the residual stress distribution characteristics of the weldment, experimental and theoretical basis for the prediction and control of the residual stress of the weldment, to optimize the welding process. The YAG laser thickness of 1.2mm flat 2A16 aluminum alloy welded analysis including the operating current, welding speed, from the amount of coke and other factors weld and welding macro quality law. Also 2A16 the hardness performance testing of the laser welded joints, and the use of OM the SEM means of observation of the microstructure of the aluminum alloy laser welded joints. The experimental results indicate that the defocus amount is the key factors that affect whether penetration. Pores and cracks in the laser welding defects by optimizing the process to reduce the probability of defects by X-ray detection, prove that no significant presence of cracks in the weld aluminum laser welding suitable process parameters: operating current I = 380A , pulse width w = 6ms, the frequency f = 8Hz, welding speed v = 90mm/min, the gas flow rate h = 5L/min, the defocus amount F = 2mm. The hardness of the weld zone was significantly higher than the base metal, layered morphology found by metallographic observation. Laser through the APDL secondary development language based on ANSYS software using Gaussian heat source model and the finite element simulation of temperature field of laser welded joints, established in line with the laser welding temperature field of finite element model, and divided into the appropriate grid; welding loading and unloading of moving heat source. Solve the problem of mathematical modeling of welding heat source mobile to discuss the heat source moving speed, laser heating parameters such as the effective radius of influence on the results. The results show that the the simulated isotherm shape and test the resulting isotherm shape is consistent. On the basis of the simulation of the temperature field, stress field simulation using the indirect method, the thermal stress and residual stress of the welding process prediction.

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Welding, metal cutting and metal bonding > Welding process > Special welding > Laser welding
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