Several common welding methods for welders

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 material to form a weld. According to the process standards of manual arc welding, it mainly includes four welding methods: flat welding, vertical welding, horizontal welding and overhead welding:. Flat welding

Ⅰ. Select a qualified welding process, electrode diameter, welding current, welding speed, welding arc length, etc., and verify through welding process tests.

2. Clean the weld: Before welding, check whether the groove and assembly gap meet the requirements, whether the positioning weld is firm, and there should be no oil or rust around the weld.

3. The baking electrode should meet the specified temperature and time. The electrode taken out of the oven should be placed in the electrode insulation barrel and taken out as needed.

4. Welding current: Select the appropriate welding current based on factors such as the thickness of the weldment, welding layer, electrode model, diameter, and welder proficiency.

5. Arc striking: The arc starting and ending points of fillet welds should be at the ends of the welds, preferably greater than 10mm. Do not strike the arc randomly. After striking the arc, the electrode should be pulled away from the weld area immediately to keep a gap of 2 to 4mm between the electrode and the component to generate an arc. The butt welds and fillet welds should be connected in time. Arc striking plates and lead-out plates should be set at both ends of the welds. The arc must be struck on the arc striking plates before welding to the weld area. For midway joints, the arc should be struck 15 to 20mm in front of the weld joint. After preheating the weldment, the electrode should be returned to the starting point of the weld. After filling the molten pool to the required thickness, welding can be carried out forward.

6. Welding speed: Welding at a constant speed is required to ensure uniform thickness and width of the weld. It is advisable to keep the same distance (2 to 3mm) between the molten iron and the slag in the molten pool from the mask.

7. Welding arc length: Determined according to different welding rod models. Generally, the arc length is required to be stable. Acid welding rods are generally 3-4mm, and alkaline welding rods are generally 2-3mm.

8. Welding angle: Determined according to the thickness of the two welds. There are two aspects of the welding angle. One is that the angle between the welding rod and the welding forward direction is 60-75°; the other is that there are two situations between the welding rod and the left and right angles of the welding. When the thickness of the welds is equal, the angle between the welding rod and the weld is 45°; when the thickness of the welds is unequal, the angle between the welding rod and the thicker weld should be greater than the angle between the welding rod and the thinner weld.

9. Arc closing: At the end of each weld, the arc pit should be filled, and the arc should be carried in the opposite direction of the welding direction to make the arc pit fall inside the weld to prevent the arc pit from biting the meat. After welding, the arc plate should be cut off by gas cutting and polished. It is not allowed to be knocked off with a hammer.

10. Slag removal: After the entire weld is welded, the slag is removed. After the welder self-checks (including appearance and weld size, etc.) and confirms that there are no problems, the welding location can be moved to continue welding.

Ⅱ. Vertical welding

The basic operation process is the same as flat welding, but the following issues should be noted:

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

2. Short arc welding is used, and the arc length is generally 2 to 3 mm.

3. The electrode angle is determined according to the thickness of the weldment. When the thickness of the two weldments is equal, the angle between the welding rod and the left and right directions is 45°; when the thickness of the two weldments is unequal, the angle between the welding rod and the thicker weldment should be greater than the angle between the thinner side. The welding rod 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 closure: When the welding is finished, the arc pit is filled with the arc discharge method, and the arc is moved to the center of the molten pool to stop the arc. It is strictly forbidden to let the arc pit fall aside. In order to prevent biting, the arc should be lowered to change the electrode angle, so that the electrode is perpendicular to the weldment or blown slightly downward by the arc.

Ⅲ. Horizontal welding

Basically the same as flat welding, the welding current is 10% to 15% lower than the current of flat welding under the same conditions, and the arc length is 2 to 4 mm. The angle of the electrode should be tilted downward during horizontal welding, and the angle is 70° to 80° to prevent the molten iron from falling. According to the different thicknesses of the two weldments, the electrode angle can be adjusted appropriately, and the electrode and the welding forward direction are 70° to 90°.

Ⅳ. Overhead welding

Basically the same as vertical welding and horizontal welding, the angle between the electrode and the weldment is related to the thickness of the weldment, the electrode and the welding direction are at an angle of 70° to 80°, and it is suitable to use small current and short arc welding.