【作者】 王锴；

【导师】 刘金合；

【作者基本信息】 西北工业大学 ， 材料加工工程， 2007， 硕士

【摘要】 惯性摩擦焊接技术是一种高效、节能的先进固态连接方法。因其控制参数少、工艺简单、自动化程度高、接头质量稳定等优点，在航空航天、汽车、能源等许多领域有着非常广阔的应用前景。 传统的惯性摩擦焊工艺从焊接自动化和质量的稳定性、可重复性出发，通常采用大转动惯量、低转速、大压力。这种工艺参数下，接头温度峰值低；热影响区易扩大；制动扭矩大，接头质量控制困难。为了避免这些问题，本文对GH4169合金惯性摩擦焊采用小转动惯量、高转速、两级压力的工艺参数进行了研究。结果观测到各组试样顶锻时瞬时升温明显，均出现了火花飞溅现象。通过接头显微组织分析，发现接头晶粒过渡匀称且均细于母材，无未焊透、飞边裂纹和撕裂等缺陷；通过焊接过程中接头温度场的测量，发现在能量输入相同的条件下转速越高，摩擦界面温度峰值越高，轴向温度梯度越大，热影响区越窄；顶锻压力越大，飞溅现象越明显，瞬时升温过程越短，界面峰值温度越高。基于实验结果，进行了接头形成分析，比较了大转动惯量与小转动惯量两种焊接规范接头的性能，并总结了常见焊接缺陷。 本文还根据惯性摩擦焊两级压力焊焊接过程的特点，结合金属材料塑性成形过程的大变形热-弹塑性理论、虚功原理和摩擦学理论，运用有限元软件ANSYS建立了GH4169合金惯性摩擦焊接过程的二维轴对称热力耦合模型。该模型假设热辐射、热对流对温度场的影响极小，无飞溅现象，基于实测转速和给定的边界条件，计算了焊接过程的瞬态温度场、应力应变场和塑性流动。通过测温实验，检验了模拟结果，发现模拟结果与实验温度场吻合得非常好。最后结合模拟结果，对焊接温度场、应力应变场的变化规律及塑性流动特征进行了分析，讨论了影响模拟结果的诸多因素。更多还原

【Abstract】 Inertia friction welding (IFW) is an advanced solid state joining process, which has the characters of excellent efficiency and energy-saving. It has been pretty extensively used in many industry fields, such as automobile、aerospace、automobile and energy, as a result of the features of less process parameters、high automation、 steady quality of welding joints and so on.Conventional inertia friction welding process usually includes big inertia, low rotational speed and powerful axial pressure, under consideration for welding automation and making welding line steady excellent performance and reappearance. In these conditions, it is easy to find of lower temperature-peak in friction interface, easily inducing heat affected zone (HAZ) extending, hardly controlling joint quality because of huge brake torque. In order to avoid these defects, IFW of GH4169 alloy with little inertia, high rotational speed and tow-rank axial pressure has been investigated in present dissertation. When forging, the phenomenon of transient rising of interface temperature is so explicit that flash appears in each process. According to microstructure analysis of welds, the joints have symmetry transition of grains which are finer than basic material’s, no defects of un-welded, splash cracks, tear-flaws et; according to measure temperatures of joints in welding process, with the same input energy the higher rotational speed is, the higher temperature peak of interface appears, the less grads of axial temperature are, the more narrow HAZ is; the power forging pressure is, the clearer flashes take up, the shorter the time of instant increasing of interface temperature undergoes, the high peak temperature in interface arrives. On the base of these results, this paper states welds forming mechanism, comparing performance of weld lines in the condition of upper tow criterions, and summarizing several familiar detects of IFW.Meanwhile, referring to features of IFW under tow-rank pressure criterion, combining with large forming thermo-elastic-plastic theoretics in metal plasticity formation, virtual work principle and tribology rules, a tow-dimension axi-symmetric thermo-mechanical coupled finite element model was established to simulate temperature field and stress-strain fields of this process by using FEM analysis software ANSYS. In the case of thermal radiation and convection slightly effecting temperature field and no flash, this model calculates transient temperature field, stress-strain fields and plastic flow during welding in the terms of experimental speed and authorized boundary condition. Measuring temperature to validate simulation results, the calculated temperature agrees well with the experimental更多还原