Phenomena and hazards

During welding, the same arc voltage shall be selected regardless of backing, filling, covering and groove size.In this way, it may not reach the required penetration and width, resulting in undercut, porosity, spatter and other defects.

Prevention and control measures

Generally, according to different situations, the corresponding long arc or short arc should be selected to obtain better welding quality and working efficiency. For example, the short arc operation should be used for the purpose of bottom welding to obtain better penetration; the arc voltage can be appropriately increased for the purpose of obtaining higher efficiency and width of penetration when filling or covering welding.

Do not pay attention to control the arc length during welding

Phenomena and hazards

During welding, the arc length shall not be adjusted properly according to groove form, number of welding layers, welding form, electrode model, etc.Due to the improper application of welding arc length, it is difficult to obtain high-quality welds.

Prevention and control measures

In order to ensure the weld quality, the short arc operation is generally adopted during welding, but the appropriate arc length can be selected according to different situations to obtain the optimal welding quality. For example, the first layer of V-groove butt joint and fillet joint shall be suitable for the shorter arc to ensure the penetration of welding without undercut; the second layer can be slightly longer to fill the weld.When the gap is small, the short arc should be used. When the gap is large, the arc can be slightly longer and the welding speed can be accelerated.The arc of overhead welding shall be the shortest to prevent molten iron from flowing down; in order to control the temperature of weld pool, small current and short arc welding shall also be used in vertical welding and horizontal welding.In addition, no matter what kind of welding is adopted in the process of movement, it is necessary to keep the arc length basically unchanged, so as to ensure the same weld width and penetration.