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Q345E钢已成为轨道交通车辆转向架焊接制造常用的结构材料。焊后去应力退火热处理工艺(传统SR工艺)可消除焊接残余应力,减小焊接过程中的变形,降低焊接裂纹敏感性,是转向架焊接制造的重要工序。但传统的SR处理,耗时过长,工序繁琐。采用优化的去应力退火热处理工艺(优化的SR工艺)可以减少耗时时长,降低工序的繁琐性。本文针对Q345E低合金高强钢材料的MAG焊焊接工艺,对试件进行去应力退火热处理工艺试验。这对于焊接工艺的实际生产具有十分重要的应用价值以及现实意义。本次试验通过对焊接试件进行焊后去应力退火工艺,观察焊接试件母材区、焊缝区、熔合区金相组织的形貌特征;进行焊接试件维氏硬度的实验观察;采用ZDL-1型钻孔装置对焊接试件的母材处、焊缝处以及焊趾处进行盲孔法焊后残余应力的测量。通过实验得出两种去应力退火工艺的焊接试件金相组织一致且均有少量的细化现象;两种工艺下的焊缝处硬度值均在180HV左右,热影响区均在185HV左右;两种工艺下的焊缝及焊趾处的残余应力都有大幅度降低,约下降了250MPa。可见优化的SR工艺与传统的SR工艺无较大差异。
Q345E steel has become the common structural material for railcar bogie welding. After the stress relief annealing heat treatment process (the traditional SR process) to eliminate welding residual stress, reduce the deformation during welding, reduce the susceptibility to weld cracking is an important process of bogie welding. However, the traditional SR processing takes too long and complicated procedures. Optimized stress relief annealing heat treatment process (optimized SR process) can reduce the time and reduce the tedious process. In this paper, for the MAG welding process of Q345E low-alloy high-strength steel, the specimens were subjected to stress-relief annealing process. This has very important application value and practical significance for the actual production of welding process. In this test, the stress-relief annealing process was used to observe the topography characteristics of the base metal, weld zone and fusion zone of the welding specimen. The experimental observation of the Vickers hardness of the welding specimen was carried out. ZDL-1-type drilling device on the welding specimen base metal, weld and weld toe at the blind hole method after welding residual stress measurement. The results show that the microstructure of the welded specimens of the two stress relief annealing processes is uniform and has a small amount of refinement. The hardness values of the welds under both of the two processes are about 180 HV and the heat affected zones are about 185 HV. Under the two kinds of processes, the residual stress at the weld and weld toe has been greatly reduced, about a decrease of 250MPa. It can be seen that there is no big difference between the optimized SR process and the traditional SR process.