Causing reasons of welding slag inclusion:
2) The way to backing weld back chipping may be wrong, so that the groove on both sides of root pass is too deep, and shows "W". In the rapid heat welding, the slag flowing into the deep trough is too late to overflow and form slag.
3) At 6 o'clock position, arc too fast is also easy to produce slag.
2) When back chipping the root weld bead will be clear into the "U" shaped groove, and avoid to be the "W" shaped slot.
3) When retreating the arc at 6 o'clock we need to fill the molten pool, and then move arc to the forming of the weld to collect arc, and use flat swing method to extinguish the arc.
Causing reasons of stomata defect:
2) The amplitude of swing of welding rod is too large when cosmetic welding, the molten pool is be protected badly.
3) The root gap is too small, which is easy to produce root needle bubble.
4) The electrode is not used for a specified period of time or prolonged exposure to air.
2) We should use the appropriate transport technology to weld, otherwise it will make the molten pool ahead, and easy to cause long short circuit and the electrode stick on the weld, which is unfavorable to deoxidize and easy to produce pores. But the width of electrode swing should not exceed twice the diameter of the electrode, otherwise it is easy to produce pores.
3) We should prevent the group on the gap is too small, if the group on the gap is too small, it will cause overlarge base metal dilution effect in the welding, and impede the exhaust, which will results in the root of bubbles.
4) Electrode should be stored in the electrode insulation tube in the use of the process. It is strictly prohibited that welding rod is exposed outward, we need to prevent the welding rod damp.