【作者】 刘凯；

【导师】 武传松；

【作者基本信息】 山东大学 ， 材料加工工程， 2021， 硕士

【摘要】 转向架是高速列车的核心部件。在转向架的制造过程中,GMAW焊接是主要的成形工艺。在焊接过程中,不可避免地会产生残余应力和变形,影响到高速列车的运行可靠性和安全性。磁控高速GMAW既提高了焊接效率,又抑制了驼峰、咬边等焊缝成形缺陷,在转向架制造过程中有很大的应用潜力。但是,常规GMAW与磁控高速GMAW用于转向架焊接时,所产生的应力与变形有何不同?目前尚不清楚。建立磁控高速GMAW与常规GMAW的等效热源模型,对其典型接头的应力与变形开展有限元分析,并对其应用到转向架的焊接过程进行预研,具有重要意义。使用Simufact Welding软件,建立了磁控高速GMAW与常规GMAW的等效热源模型,并根据焊缝截面熔合线和熔池长度、热循环曲线以及残余应力的测试与计算结果进行了验证。以转向架侧梁的局部模型T型接头多层多道焊为研究对象,对比分析了 T型接头在磁控高速GMAW与常规GMAW时的温度场、应力场、以及变形场。结果表明,在T型接头上,磁控高速GMAW的峰值温度大于常规GMAW,冷却速度快于常规GMAW。磁控高速GMAW时残余应力和变形均小于常规GMAW。提取了 T型接头焊缝上不同位置的热循环曲线作为热循环法的输入,与热弹塑性法的计算结果进行比较,找到了焊缝边缘中心位置为热循环曲线的最佳取点位置。提取每一道焊缝的热循环曲线,并将其作为转向架侧梁数值模型的输入量。对比分析了转向架侧梁在磁控高速GMAW与常规GMAW两种焊接工艺条件下残余应力与变形的分布情况,考察磁控高速GMAW时四种不同焊接顺序对侧梁应力和变形的影响。结果表明,磁控高速GMAW条件下的转向架侧梁的残余应力与变形大小都小于常规GMAW,在磁控高速GMAW的四种焊接顺序中,焊接顺序一为最优焊接顺序。更多还原

【Abstract】 The bogie is a key core component of high-speed trains.In the manufacturing process of the bogie,GMAW welding is the main forming process.During the welding process,residual stress and deformation will inevitably occur,which will affect the operational reliability and safety of high-speed trains.magnetic-assisted GMAW not only improves welding efficiency,but also suppresses weld forming defects such as hump and undercut.It has great application potential in the bogie manufacturing process.However,when conventional GMAW and magnetic-assisted GMAW are used for bogie welding,what is the difference in stress and deformation?Do not know yet.It is of great significance to establish the equivalent heat source model of magnetic-assisted GMAW and conventional GMAW,carry out finite element analysis on the stress and deformation of its typical joints,and conduct pre-research on the welding process of its application to the bogie.Using Simufact Welding software,the equivalent heat source model of magnetic-assisted GMAW and conventional GMAW was established,and verified according to the test and calculation results of weld cross-section fusion line and weld pool length,thermal cycle curve and residual stress.Taking the local model T-joint multi-pass welding of the bogie side beam as the research object,the temperature field,stress field and deformation field of the T-joint in the magnetic-assisted GMAW and the conventional GMAW are compared and analyzed.The results show that the peak temperature of the magnetic-assisted GMAW is higher than that of the conventional GMAW on the T-joint,and the cooling rate is faster than that of the conventional GMAW.The residual stress and deformation of magnetic-assisted GMAW are smaller than those of conventional GMAW.The thermal cycle curves of different positions on the T-joint weld are extracted as the input of the thermal cycle method,compared with the calculation results of the thermo-elastoplastic method,and the center of the weld edge is found to be the best point of the thermal cycle curve.Extract the thermal cycle curve of each weld and use it as the input of the bogie side beam numerical model.The distribution of residual stress and deformation of bogie side beams under the two welding conditions of magnetic-assisted GMAW and conventional GMAW are compared and analyzed,and the influence of four different welding sequences on the side beam stress and deformation in magnetic-assisted GMAW is investigated.The results show that the residual stress and deformation of the bogie side beams under the condition of magnetic-assisted GMAW are smaller than those of conventional GMAW.Among the four welding sequences of magnetic-assisted GMAW,the first welding sequence is the optimal welding sequence.更多还原