1, is the weld of the object cleaned?
Because in many cases, the weld is very dirty, including iron oxide, slag shell, oxide rust on the base material and so on. So as to ensure the welding quality.
2. Clean the nozzle of the second welding torch, and the wire feeding tube should not be excessively bent to ensure the smooth wire feeding of the conductive nozzle, so as not to affect the current and voltage.
3. Sufficient carbon dioxide gas. Try to avoid wind sources and avoid air holes.
4. In the welding process, splashing will occur. The greater the voltage ratio, the less splash, the larger the particles, the higher the heat, and it is not easy to clean.
The smaller the voltage ratio, the more splashes and smaller particles, and the easier it is to clean.
It is suggested to coat a layer of anti-sticking agent or vinegar on both sides of the weld before welding, which can prevent spatter from sticking to objects and improve production efficiency.
5. There are left welding method and right welding method, with left welding method from right to left and right welding method from left to right.
Left welding method: the penetration depth is easy to observe the weld, the width is large, the residual height is small and the splash is small. Non-ferrous metals must remain welded.
Correct welding method: penetration depth, easy observation of molten pool, small width, high height and large splash.
6. When welding, don't hold the gun mouth too high. If it is too high, it will easily lead to blowholes and wire jumping.
The nozzle is about 8-15mm away from the weld. Don't press it too low, it is not easy to observe the weld, and it will burn the nozzle. If the wire is fed too fast, air holes will appear and the weld will not be well formed.
7. Commonly used welding gun conveying methods for secondary welding, such as sawtooth, triangle, crescent and circle. When the weld is small, it is round and triangular, and when the weld is large, it is better to transport the gun with crescent sawtooth.
8. It is most important to adjust the current and voltage during the second shielded welding, because the parameters of current and voltage are not easy to remember, and the unit welder is not necessarily easy to use, so it is very practical to adjust the current and voltage by observing the transition mode.
9. The formation process of welding wire melting into weld is transition, which can be divided into three types: particle transition, sword transition and short circuit transition.
When we weld, we can see that when the welding wire is converted into solution, the welding wire will become a big particle. When the particles on the welding wire head are too large, the wire feeding slows down, which proves that the voltage is too high. This is a short-circuit transition, with less splash, difficult cleaning and high heat.
When the transition particle is slightly larger than the diameter of the welding wire, it belongs to particle transition, which is widely used and the current-voltage ratio is normal.
When the excess particles are equal to the diameter of the welding wire, it is a sword transition, with small current ratio, more splash and less heat. When the current is small, there will be wire jumping and poor forming.
10. When welding, the conveying mode and speed of the welding torch must be coordinated with the adjusted current and voltage. If the cooperation is not good, there will be some shortcomings, such as unevenness, weld sag, excessive height and weld subsidence.
Arc closing function, because after a weld is welded, arc pits are easy to appear. Don't take the welding torch too early, and take it away after the weld is fully formed to avoid arc pits. The weld pit at the end of the weld is closed by the arc closing function. Make the weld appearance beautiful and ensure the quality. When the arc switch is turned on, the welding wire feed becomes automatic.
You don't need to hold down the switch with your finger. When the welding seam is almost finished, press and hold the torch switch with your fingers, and don't release it, which will become the current and voltage of arc closing. After the arc is closed, loosen your fingers to complete the welding.
Double shielded welding is short for carbon dioxide gas shielded welding, which is an open arc welding method with carbon dioxide as shielding gas, covered electrode as welding wire and filler.
It has the characteristics of high efficiency and energy saving, good weld quality, strong rust resistance, wide application range, easy observation of open arc, no slag and strong penetration.
The welding speed is fast, the object is less heated and the deformation is small.