CO2 gas shielded welding is the melting energy of welding wire provided by welding voltage.
The higher the voltage is, the faster the welding wire melts;
The welding current is actually the result of the balance between wire feeding speed and melting speed.
1. Welding current
The welding current shall be selected according to the welding conditions (plate thickness, welding position, welding speed, material and other parameters).
Therefore, the carbon dioxide gas shielded welding current must match the welding voltage, and the wire feeding speed and welding voltage must be consistent with the melting capacity of the welding wire to ensure the stability of the arc length.
For the same welding wire, the larger the cable is, the faster the wire feeding speed is.
With the same current, the thinner the welding wire, the faster the wire feeding speed.
2. Welding voltage
Welding voltage, namely arc voltage, provides welding energy.
The higher the arc voltage, the greater the welding energy, the faster the welding wire melts, and the greater the welding current.
The arc voltage is equal to the output voltage of the welder minus the loss voltage of the welding circuit, which can be expressed by the following formula:
Uarc = Uoutput – Uloss
If the installation of the welding machine meets the installation requirements, the voltage loss mainly refers to the voltage loss caused by the extension of the cable.
If the welding cable needs to be extended, the output voltage of the welding machine can be adjusted according to the following table:
|Welding current Cable length||100A||200A||300A||400A||500A|
|10m||About 1V||About 1.5V||About 1V||About 1.5V||About 2V|
|15m||About 1V||About 2.5V||About 2V||About 2.5V||About 3V|
|20m||About 1.5V||About 3V||About 2.5V||About 3V||About 4V|
|25m||About 2V||About 4V||About 3V||About 4V||About 5V|
3. Setting of welding voltage
Select the welding current of the corresponding plate thickness according to the welding conditions, and then calculate the welding voltage according to the following formula:
＜ 300A: welding voltage=(0.05 × Welding current+14 ± 2) V
＞ 300A: welding voltage=(0.05 × Welding current+14 ± 3) V
Example 1: If the welding current is 200A, the welding voltage is calculated as follows:
Welding voltage=(0.05 × 200+14 ± 2）
=(10+14 ± 2) V
=(24 ± 2) V
Example 2: If the welding current 400A is selected, the welding voltage is calculated as follows:
Welding voltage=(0.05 × 400+14 ± 3）
=(20+14 ± 3) V
=(34 ± 3) V
4. Influence of welding voltage on welding effect
When the voltage is too high: the arc length becomes longer, the spatter particles become larger, which is easy to produce pores, the weld bead becomes wider, the solution depth and surplus height become smaller, and there is a “patter! Patter!” Sound.
When the voltage is low: when the welding wire is inserted into the base metal, the spatter increases, the weld bead narrows, the solution depth and surplus height increase, and there is a “Bang! Bang! Bang!” Sound.