In the process of steel pipe welding, there are a lot of precautions. If you neglect it, you may make a big mistake. You don't pay attention to choosing the appropriate voltage in welding construction. Whether it's priming, filling, capping, or groove size, you should choose the same arc voltage. In this way, you may not achieve the required penetration, width, undercut, porosity, spatter, and other defects, Generally, the corresponding long arc or short arc should be selected according to different conditions to obtain better welding quality and work efficiency.

Welding does not control the welding current. In order to speed up the welding process, the butt weld of medium and heavy plates is not beveled, the strength index drops, or even fails to meet the standard requirements. Cracks appear in the bending test, which will not guarantee the performance of the welded joint and pose a hidden danger to structural safety. The welding should be controlled according to the welding current in the process evaluation, allowing 10 ~ 15% floating, The size of the blunt edge of the groove shall not exceed 6 mm. When the plate thickness exceeds 6 mm, the groove shall be opened for welding.

The coordinated use of welding speed, welding current, and electrode diameter is not paid attention to. The control of welding speed and welding current is not careful, and the electrode diameter and welding position are used in coordination. For example, when backing welding a full penetration fillet weld, due to the narrow root size, if the welding speed is too fast, the root gas and slag do not have enough time to discharge, it is easy to cause the root incomplete penetration Slag inclusion, porosity, and other defects.

If the welding speed is too fast, it is easy to produce air holes, if the welding speed is too slow, the weld reinforcement will be too high, and the shape will be irregular. When welding thin plate or small blunt edge weld, the welding speed is too slow, and it is easy to burn through. The welding speed has a great impact on the welding quality and welding production efficiency. When selecting, it should be combined with the welding current, weld position, weld thickness, and groove size, Select the appropriate welding speed, in the guarantee penetration, gas, and slag easy to discharge, not burn through, forming a good premise, choose a larger welding speed, increase production efficiency.

When welding, the arc length is not controlled. The arc length is not properly adjusted according to the groove form, welding layer number, welding form, and electrode type. Due to the improper use of welding arc length, it is difficult to obtain high-quality welds.

In order to ensure the welding quality, the short arc operation is generally adopted, but the appropriate arc length can be selected according to different conditions to obtain the appropriate welding quality. For example, the first layer of the V-groove butt joint and fillet joint should use a shorter arc to ensure penetration and avoid undercut. The second layer can be slightly longer to fill the weld. When the weld gap is small, the short arc should be used. When the gap is large, the arc can be slightly longer, No matter what kind of welding is adopted, the arc length should be kept unchanged during the movement, so as to ensure that the width and depth of the whole weld are consistent.

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