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焊接时由于管件结构尺寸和形状的限制，双面焊接有时是不可能的。只能开单面坡口的特殊操作方法是单面焊双面的技术，这是手工电弧焊的一项高难度操作技能。 Due to the limitation of pipe structure size and shape, double-sided welding is sometimes impossible. The special operation method of only one side groove is the technology of one side welding and two sides, which is a difficult operation skill of manual arc welding.
立焊时，在重力作用下，由于熔池温度过高，被覆焊条熔化形成的熔滴与熔池中的铁水容易滴落形成焊瘤，焊缝两侧形成咬边。 During vertical welding, due to the high temperature of the molten pool under the action of gravity, the molten droplets formed by the melting of the covered electrode and the molten iron in the molten pool are easy to drip to form weld beading, and undercut is formed on both sides of the weld. 温度过低时，容易出现夹渣，反面容易形成未焊透、焊瘤等缺陷，造成焊缝成型困难。 When the temperature is too low, slag inclusion is easy to occur, and defects such as incomplete penetration and weld beading are easy to form on the reverse side, resulting in difficulty in weld forming.
熔池的温度不容易直接识别，但与熔池的形状和大小有关。因此，在焊接过程中，通过仔细观察和控制熔池的形状和大小，可以达到控制熔池温度和保证焊接质量的目的。 The temperature of molten pool is not easy to identify directly, but it is related to the shape and size of molten pool. Therefore, in the welding process, by carefully observing and controlling the shape and size of the weld pool, the purpose of controlling the weld pool temperature and ensuring the welding quality can be achieved. 根据老师傅十几年的经验，总结出以下规律： According to the experience of teacher Fu for more than ten years, the following rules are summarized: 焊条角度很重要，焊接规范不可或缺。 Electrode angle is very important and welding specification is indispensable.
在垂直焊接过程中，由于焊条熔化形成的熔滴，熔池中的铁水容易滴下形成焊瘤，以及焊缝两侧的咬边，焊缝的成形变差。掌握正确的焊接规范，根据焊接条件的变化，调整焊条角度及运条的速度。 In the process of vertical welding, due to the droplets formed by the melting of the electrode, the molten iron in the molten pool is easy to drop and form weld beading, as well as the undercut on both sides of the weld, the weld formation becomes worse. Master the correct welding specification, adjust the electrode angle and the speed of electrode transportation according to the changes of welding conditions. 焊条与焊件表面的左右夹角为90度，开始焊接时与焊缝的夹角为70 ~ 80度，中间为45 ~ 60度，完成焊接时为20 ~ 30度。装配间隙为3 ~ 4毫米 ，应选择较小的焊条直径 3.2毫米 ，使用较小的焊接电流，打底焊为110~115A，中间过渡层为115~120A，覆盖层为105~110A。 The included angle between the electrode and the surface of the weldment is 90 degrees, the included angle between the electrode and the weld is 70 ~ 80 degrees at the beginning of welding, 45 ~ 60 degrees in the middle, and 20 ~ 30 degrees at the completion of welding. The assembly gap is 3 ~ 4mm, the smaller electrode diameter of 3.2mm shall be selected, and the smaller welding current shall be used. The backing welding is 110 ~ 115a, the intermediate transition layer is 115 ~ 120a, and the covering layer is 105 ~ 110A. 一般电流比平焊小12％ ~ 15％，以减小熔池体积，减少重力影响，利于熔滴过量。采用短弧焊接，缩短熔滴到熔池的距离，形成短路过渡。 Generally, the current is 12% - 15% less than that of flat welding, so as to reduce the volume of molten pool and the influence of gravity, which is conducive to excessive droplet. Short arc welding is adopted to shorten the distance from droplet to molten pool and form short-circuit transition. |
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