【作者】 郁雯霞；

【导师】 雷玉成；

【作者基本信息】 江苏大学 ， 材料加工工程， 2006， 硕士

【摘要】 焊接过程是一个迅速而又极不均匀的物理化学冶金过程，焊接熔池一直是焊接模拟的一个重要领域。本文根据能量守恒的基本原理和钨极氩弧焊（TIG）工艺的特点，建立了运动电弧作用下T3紫铜非稳态TIG焊接熔池形态的数值分析模型，并采用有限元的方法对模型进行了离散化处理。该模型综合考虑了使熔池金属产生运动的浮力、电磁力、表面张力等驱动力，同时考虑了材料的热物理性能参数随温度的变化、焊接过程中熔池与外界的能量的交换，以及熔化／凝固相变对熔池流场及温度场的影响。文中采用的表面分布双椭圆热源模型，较好地符合了TIG焊接热流分布的形态。 作者在不预热的情况下采用氩氮混合保护气体对厚壁紫铜进行了TIG焊接工艺的研究，并研究了不同比例下氩氮混合气体对焊接接头微观组织和力学性能的影响。 根据TIG焊接熔池温度场和流场的特点，本文利用通用有限元软件ANSYS，采用非均匀网格对单元进行了划分，使用热源叠加的方式对TIG焊接熔池热量的吸收进行了处理，对所建立的数学模型进行了求解。模拟结果展示了T₃紫铜TIG焊接瞬态熔池的建立过程。初步计算了焊接电流和焊接速度对焊接温度场分布的影响。通过焊接工艺实验，比较了焊缝熔宽和熔深的测量结果和计算结果，结果表明本文所建模型的计算值和实际测量值较为吻合，验证了所建立的模型和采用的软件方法的正确性和可靠性。更多还原

【Abstract】 The welding is a rapid and extremely physicochmemical metallurgical process. Welding pool is an important domain of welding simulation all along. In this paper, according to conservation of energy principle and technology characteristics of tungsten inert gas（TIG）, a model of non-steady three-dimensional temperature field for T₃ red copper’s TIG welding with a locomotive arc was established. Discretization treating has been carried out on model with the method of finite element. The driving force of buoyancy、 electromagnetic force and surface tension have been synthetically considered in the model. At the same time, the variation of temperature-dependent material thermophysics performance ,the energy change between welding pool and environment and the influence of melting/solidifying of phase changes for flow field and temperature field have also been considered.Indrafted the surface distribution dual-ellipsoid model, and the demands of welding numerical simulation was primely satisfied.The author studied the TIG welding of thick-wall red copper adopting Ar+N₂ without preheating. Microstructure and mechanical properties of welding splice were also studied under different proportion of Ar+N₂.According with characteristics of TIG welding pool temperature felid and flow felid, elements were divided by using non-uniform grid in the finite element software ANSYS. In this study, heat absorbing of TIG welding pool was treated by splicing heat source. And the math model was solved. Simulation results showed the creation of TIG transient welding pool. The effect of welding current and welding speed to temperature field distribution was calculated. Comparing the experiment value and the calculation value under different technological parameter, the results indicated that the model and practical course were well matched, proved that the model was reliable and correct.更多还原