CO2 gas shielded welding (often known as Mig welding) is the most commonly used working method for welders, but the biggest disadvantages of this welding method is that it will spatter during welding. To reduce the splash of CO2 gas shielded welding, the following measures can be taken.
1. Selection of correct welding parameters
(1) Select the appropriate current range
In CO2 gas shielded welding, for welding wires of different diameters, there is a law between the spatter rate and the welding current. In the short-circuit transition area of small current or the fine particle transition area of high current, the spatter rate is small, and only the current in the middle area will cause higher spatter rate.
(2) The length of wire extension
The extension length of the welding wire also affects the spatter of welding. Extension length of 20mm-30mm will bring higher spatter rate, so try to reduce the extension length of the welding wire during welding, thereby reducing the spatter rate.
2. Improve power supply
The cause of spatter in CO2 gas shielded welding is mainly that at the end of the short-circuit transition, due to the sharp increase in current, the metal heats up rapidly, and the heat accumulation causes the liquid bridge to burst and generate spatter. Methods such as series resistance, current switching, and current waveform control in the welding circuit can be used to reduce the burst current of the liquid bridge and reduce spatter.
3. Add argon (Ar) to CO2 gas
By adding argon to change the physical and chemical properties of CO gas, as the proportion of argon increases, the spatter rate of the particles larger than 0.8mm decreases gradually. Adding argon can not only reduce the spatter rate, but also reduce the penetration depth, increase the fusion width, and reduce the weld reinforcement.
4. Use low spatter welding wire
For solid welding wire, under the premise of ensuring the mechanical properties of the joint, by reducing its carbon content as much as possible, and then appropriately increasing alloy elements such as titanium, aluminum, etc can effectively reduce spatter. Flux-cored wire CO2 gas shielded welding can reduce the spatter rate too, its spatter rate is about 1/3 of that of solid wire.
5. Angle control of welding torch
When the welding torch is welded perpendicular to the weldment, the amount of welding spatter generated is the least, and the larger the inclination angle is, the more spatter there will be, so the inclination angle of the welding torch is best not to exceed 20° during welding.