When welding, the same arc voltage is used regardless of the size of the bevel, regardless of the size of the groove. In this way, the required penetration depth and width may not be achieved, and defects such as undercuts, pores, and splashes may appear.

Generally, for different situations, the corresponding long arc or short arc should be selected to obtain better welding quality and work efficiency.

For example, short arc operation should be adopted in order to obtain a good penetration when welding at the bottom, and arc voltage can be appropriately increased in order to obtain higher efficiency and welding width when filling welding or cover welding.

When welding, in order to rush the schedule, we do not open the groove for the butt welds of medium and thick plates. The strength index decreases, even does not meet the standard requirements, and cracks appear during the bending test, which will not guarantee the performance of the weld joint and pose a potential hazard to the safety of the structure.

Welding should be controlled according to the welding current in the process evaluation, and 10 to 15% floating is allowed. The size of the blunt edge of the groove should not exceed 6mm. When the butt joint is over 6mm, the groove must be opened for welding.

When welding,  pay no attention to controlling the welding speed and welding current, the diameter of the welding rod, and the welding position.

For example, when underwelding a fully fused corner seam, due to the narrow root size, if the welding speed is too fast, the root gas and slag inclusions do not have enough time to be discharged, and it is easy to cause roots such as infiltration, slag inclusions, and pores Defects; when welding the cover surface, if the welding speed is too fast, it is easy to produce pores; if the welding speed is too slow, the remaining height of the weld will be too high and the shape will be irregular; when welding thin plates or welds with small blunt edges, the welding speed Too slow, easy to burn through.

Welding speed has a significant impact on welding quality and welding production efficiency. When selecting, the appropriate welding speed should be selected in accordance with the welding current, the position of the weld (bottom welding, filling welding, cover welding), the thickness of the weld, and the bevel size. To ensure penetration, gas and welding slag are easy to be discharged without burning through, and a large welding speed is selected under the premise of good forming to improve productivity.

When welding, the arc length is not adjusted properly according to the bevel form, the number of welding layers, the welding form, and the electrode type. It is difficult to obtain high quality welds due to incorrect use of welding arc length.

In order to ensure the quality of the welding seam, short arc operation is generally used during welding, but the appropriate arc length can be selected according to different situations to obtain the optimal welding quality. A shorter arc to ensure weld penetration and undercutting does not occur. The second layer can be slightly longer to fill the weld. Short arcs should be used when the gap is small. The arc can be longer when the gap is large, and the welding speed will be faster. The overhead welding arc should be the shortest to prevent the iron from flowing underwater; in order to control the temperature of the molten pool during vertical welding and horizontal welding, a small current and short arc welding should also be used.

In addition, no matter what welding is used, it is necessary to keep the arc length basically constant during the movement to ensure that the welding width and depth of the entire weld are consistent.

For workpieces with high accuracy requirements, failure to take effective measures to control deformation will cause the installation dimensions of the workpiece to fall short of the requirements for use, and even cause rework or scrap.

Adopt a reasonable welding sequence and select appropriate welding specifications and operating methods, but also adopt anti-deformation and rigid fixing measures.