2. Vertical welding: The basic operation process is the same as that of flat welding, but the following issues should be paid attention to:

2.1 Under the same conditions, the welding power source is 10% to 15% smaller than the flat welding current.

2.2 Adopt short arc welding, the arc length is generally 2～3mm.

2.3 The angle of the electrode is determined according to the thickness of the weldment. The thickness of the two weldments is equal, and the angle between the electrode and the electrode in the left and right directions is 45°; when the thickness of the two weldments is different, the angle between the electrode and the thicker weldment should be greater than the angle on the thinner side. The welding rod should form an angle of 60°～80° with the vertical surface, so that the arc is slightly upward and blows toward the center of the molten pool.

2.4 Retracting arc: When the welding reaches the end, use the arc discharge method to fill the arc crater, and move the arc to the center of the molten pool to stop the arc. It is strictly forbidden to leave the arc crater aside. In order to prevent meat biting, the arc should be lowered and the angle of the electrode should be changed so that the electrode is perpendicular to the weldment or blown down slightly from the arc.

3. Horizontal welding: basically the same as flat welding, the welding current is 10% to 15% lower than that of flat welding under the same conditions, and the arc length is 2 to 4mm. The angle of the electrode, the electrode should be inclined downward during horizontal welding, and its angle is

70°～80°, to prevent the iron from falling under the water. According to the thickness of the two weldments, the angle of the welding rod can be adjusted appropriately, and the forward direction of the welding rod and welding is 70°～90°.

4. Overhead welding: basically the same as vertical welding and horizontal welding. The welding rod is related to the angle of the weldment and the thickness of the weldment. The welding rod is at an angle of 70° to 80° with the welding direction. It is appropriate to use small current and short arc welding.

5. Winter low temperature welding: When arc welding is performed under the condition of ambient temperature lower than 0℃, in addition to complying with the relevant regulations of normal temperature welding, the welding process parameters should be adjusted so that the weld and the heat-affected zone are slowly cooled. Windshield measures should be taken if the wind force exceeds level 4; the uncooled joints after welding should be avoided from contact with ice and snow. In order to prevent welding cracks, the steel structure should be preheated and preheated to control the temperature between layers. When the temperature of the working place is below 0℃, a process test should be carried out to determine the appropriate preheating and post-heating temperature.