There are many factors that cause metal splashing. Therefore, to reduce the splash, it is necessary to carry out specific analysis according to the actual situation and take targeted solutions.
In general, the following measures are available:
1) Power polarity selection DC reverse connection.
2) Select the appropriate welding current area.
When CO2 welding, there is a certain regularity between the spatter rate of each diameter of the welding wire and the welding current:
Generally, the current is less than 150A or greater than 300A, and the spatter rate is small, and the spatter ratio between the two is large. When selecting the welding current, the current area with high spatter rate should be avoided as much as possible. After the current is determined, the appropriate voltage is matched to ensure that the spatter rate is minimized.
3) When the welding gun is vertical, the amount of splash is the smallest, the angle of inclination is the largest, and the splash is more. It is best not to push the torch forward or backward more than 20 degrees.
4) The length of the wire extension. The length of the wire extension shall be as short as possible in the case of normal welding.
5)Add Ar gas into CO2 during long arc welding. After the addition of Ar gas to the CO2 gas, the pure carbon dioxide gas has a high thermal conductivity, decomposes and absorbs heat, and the high arc energy consumption easily leads to strong contraction of the arc column and the arc spot, which hinders the physical and chemical properties of the droplet transfer. As the proportion of Ar gas increases, the splash gradually decreases. In addition to overcoming the splash, the CO2+Ar mixed gas also improves weld formation and has an effect on weld penetration, weld height and residual height. Practice has proved that 80% Ar + 20% CO2 has the lowest spatter rate.
6) Use a low spatter rate wire.
* solid core wire. Under the premise of ensuring mechanical properties, the carbon content should be reduced as much as possible, and an appropriate amount of alloying elements such as titanium and aluminum should be added. Whether the particles are excessively welded or short-circuited, the welding can significantly reduce the splash caused by gases such as CO.
* The positive electrode is welded by using a wire which has been activated by a substance such as Cs2CO3 or K2CO3.
* Use Flux cored wire. The metal splash rate of the flux-cored wire is 1/3 of that of the solid wire.In addition, in the welding circuit, a large inductance is connected in series, so that the short-circuit current rises slowly, and the splash can be appropriately reduced.