There are several welding methods

Manual welding, also known as manual arc welding, is a manual welding method that uses an arc as a heat source to melt the electrode and the base metal to form a weld. According to the technical standard of manual arc welding, it mainly includes four welding methods: flat welding, vertical welding, horizontal welding and overhead welding:
(1) Flat welding
1. Select qualified welding process, electrode diameter, welding current, welding speed, welding arc length, etc., and verify by welding process test.
2. Clean up the welding joint: Before welding, check whether the groove and assembly gap meet the requirements, whether the positioning welding is firm, and there should be no oil stains and rust around the welding seam.
3. The baked electrode should meet the specified temperature and time. The electrode taken out of the oven should be placed in the electrode insulation bucket and taken as needed.
4. Welding current: According to the thickness of the weldment, welding level, electrode type, diameter, welder proficiency and other factors, select the appropriate welding current.
5. Arc ignition: The arc point of fillet weld should be at the end of the weld, which should be greater than 10mm. The arc should not be struck casually. After ignition and arc ignition, the electrode should be pulled away from the weld area immediately to keep the electrode and the component. 2 ~ 4mm gap to generate arc. For butt weld joint and fillet joint combined weld seam, arc strike plate and lead out plate are set at both ends of the weld seam. The arc must be struck on the arc strike plate before welding to the weld zone, and the midway joint should be in front of the weld joint. Start the arc at 15-20mm, preheat the weldment, return the electrode to the beginning of the weld, and fill the molten pool to the required thickness before welding forward.
6. Welding speed: constant speed welding is required to ensure that the thickness and width of the weld are uniform. It is advisable to maintain an equal distance (2-3mm) between the molten iron and the molten slag in the molten pool from the inside of the mask.
7. Welding arc length: It is determined according to the different types of electrodes. Generally, the arc length is required to be stable and constant. The acid electrode is generally 3-4mm, and the basic electrode is generally 2-3mm.
8. Welding angle: According to the thickness of the two weldments, the welding angle has two aspects. One is that the angle between the welding rod and the welding forward direction is 60-75°; When the thickness of the weldment is equal, the angle between the electrode and the weldment is 45°; when the thickness of the weldment is not equal, the angle between the electrode and the thicker weldment should be larger than the angle between the electrode and the thinner weldment.
9. Arc ending: After each welding seam is welded to the end, the arc crater should be filled, and the arc should be drawn in the opposite direction of the welding direction, so that the arc crater is thrown into the weld bead to prevent the arc crater from biting the meat. After welding, gas cutting should be used to cut off the arc plate, and it should be ground and smooth, and it is not allowed to be knocked down with a hammer.
10. Slag removal: After the entire weld is welded, the slag should be removed. After the welder's self-inspection (including appearance and weld size, etc.) confirms that there is no problem, the location can be transferred to continue welding.
(2) Vertical welding: The basic operation process is the same as that of flat welding, but the following issues should be paid attention to:
1. Under the same conditions, the welding power source is 10% to 15% smaller than the flat welding current.
2. Using short arc welding, the arc length is generally 2 ~ 3mm.
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 thicknesses of the two weldments are not equal, the angle between the electrode and the thicker side of the weldment should be greater than the angle on the thinner side. The electrode should form an angle of 60° to 80° with the vertical plane, so that the angle arc is slightly upward and blows toward the center of the molten pool.
4. Arc ending: When the welding reaches the end, the arc crater is filled by the arc exhaust method, and the arc is moved to the center of the molten pool to stop the arc. It is strictly forbidden to leave the crater aside. In order to prevent the meat from biting, the arc should be lowered to change the angle of the electrode, so that the electrode is perpendicular to the weldment or blown down slightly by the arc.
(3) Horizontal welding: basically the same as flat welding, the welding current is 10%~15% smaller than that of flat welding under the same conditions, and the arc length is 2~4mm. 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. According to the different thicknesses of the two weldments, the angle of the electrode can be adjusted appropriately, and the direction of the electrode and the welding advance is 70° to 90°.
(4) Overhead welding: It is basically the same as vertical welding and horizontal welding. The welding rod is related to the included angle of the weldment and the thickness of the weldment. The welding rod forms an angle of 70° to 80° with the welding direction.