Skills and technology of secondary welding;
Two-pass welding is a method of connecting metals through two welds. Firstly, two notches are made in the metal, and then welding is carried out with electrodes with opposite polarities. The key of double-sided shielded welding lies in the correct selection of covered electrode and its diameter, current and voltage. Pay attention to the following skills and techniques when welding:
1, prevent welding
Welding is one of the common problems in secondary welding. When the current is too large, the electrode diameter is too small or the operation is not right, it will lead to welding on the weld surface and affect the welding quality. Therefore, it is necessary to control the current and electrode diameter in the second welding to avoid welding.
2. Maintain a stable welding speed.
Welding speed directly affects the weld quality. Too fast welding speed and too high temperature of molten pool will lead to quality problems such as shrinkage cavity in weld. If the welding speed is too slow, it will increase the welding time and affect the working efficiency. Therefore, in secondary welding, it is necessary to control the welding speed and maintain a stable welding speed.
3, circumferential welding
The secondary welding can adopt the method of ring welding, that is, moving the electrode in a figure of eight with the center point as the center. This method can make the metal center smooth and the weld shape regular and beautiful.
Vertical welding skills and technology:
Vertical welding is a method of welding metal on two vertical planes. Different from two-way welding, the premise of vertical welding is to butt and fix two plates. Next, you need to use the correct welding tools and techniques for vertical welding. The following points are the skills and techniques that should be paid attention to in vertical welding:
1, select the appropriate welding equipment.
When vertical welding, the correct welding equipment should be selected, such as gas suitable for vertical welding and brazing points. In addition, proper airflow should be selected during vertical welding to ensure sufficient oxygen in the welding area.
2. Control the page temperature
It is necessary to control the page temperature during vertical welding. In the welding process, if the temperature in the welding area is too high or too low, it will affect the welding effect. Therefore, it is necessary to keep proper page temperature and control heat transfer.
3. Make sure the fixed position is accurate.
In vertical welding, it is necessary to ensure the accurate fixed position. Because it is necessary to use electric tools or hand tools when welding, if these tools are not fixed correctly, they will become unstable and increase the risk of accidents during welding.