During welding, the gas cylinder shall be kept stable and free from vibration and impact. The welding ground wire should be firmly connected with the pipeline to avoid the electric arc between the ground wire and the pipe wall from burning the pipeline. When welding, two welders should perform symmetrical welding, and the groove should adopt arc initiation method. It is forbidden to arc on the pipe surface outside the groove. Covered electrode should be replaced quickly during welding, and covered electrode should be replaced before the molten pool cools, and the arc should be started again. Generally, steel bars are transported by straight pulling or small swinging, and the angle between covered electrode and pipe wall should be 75 ~ 80 degrees, and the angle between and both sides should be 90 degrees. After the completion of root welding, hot-runner welding shall be carried out as soon as possible, and the interval between layers shall not exceed 10 minute. Slag and spatter must be carefully removed between layers, and the next weld can only be welded after the appearance inspection is qualified.