How Pulse Welding Works?
In other words, under no circumstances and at no time does the electrode come into contact and short with the welding pool.
This is achieved by high-speed welding current control. For a detailed consideration of the process, we will analyze its welding current plot.
In the “hot” phase of the pulse process, each pulse forms one drop of molten metal at the end of the electrode.
Then the current increases exactly to the value that is necessary to discharge this drop into the welding pool due to the pinch effect.
Then comes the “cold” phase. Unlike the CV (constant voltage characteristic) mode, the current plot of which is a straight line, during the pulse process the current is reduced to the baseline when there is no need for welding arc power (no hot arc present at this stage).
Read more: Modes of Metal Transfer in Welding
Therefore, the pulse process is colder. During the low-current welding cycle phase, the arc is maintained, the wire is heated, however, there is not enough energy to carry the metal.
The duration of the base current is limited so that the transfer of metal in large drops does not begin and thus avoiding globular transfer.
Thus, the current rises to a maximum when the weld droplet is discharged, and then decreases to a base value, thereby reducing the total heat input. Transfer control is carried out by setting the amplitude and duration of the peak value of the welding current.
The process of pulsed metal transfer in a shielding gas atmosphere is one of the best welding procedures and can be recommended for the widest range of metal types and a wide variety of applications.
When using pulse transfer on sources with synergistic control, most of the parameters of the welding process are determined by the welder by setting the type of material to be welded using a switch.
Fine-tuning of the process is possible with the help of source controls. The use of special software allows you to set fully optimized welding current plots.
What is Pulse Welding?
Pulsed metal transfer is a serious improvement in welding technology, because it combines the advantages of all other transfer methods, while being almost completely devoid of the disadvantages characteristic of these methods.
nlike the transfer of a series of short circuits, the pulse welding does not create splashes and is not prone to the formation of non-melting.
The positions in which pulsed welding can be carried out are not limited, as in the case of the jet transfer process, and the use of welding wire is much more efficient.
With less heat input compared to the microdroplet transfer method, the pulsed process allows a wider range of parts to be welded.
It is the reduction in heat input during the pulsed process that improves the quality of welding of thin materials, eliminating burns through and reducing warping, as well as allowing welding at lower wire feed speeds.
Pulsed metal transfer has evolved significantly since its introduction into production. In the 80s, it was a very complex process, which only the most experienced welders could master.
High qualification requirements were dictated by the need for an accurate knowledge of the relationship between the speed of wire feeding and the requirements of the process itself. Today, this relationship is established automatically as a synergistic connection. control loop.
If the wire feed rate changes, the control loop automatically changes the shape of the welding current plot and the pulse frequency. The process has passed the experimental stage and is ready for widespread implementation in production.
The synergistic mode of operation of the welding current source so reduces the complexity of welding that even a novice welder can confidently carry out most operations, controlling the process with a single handle.
The software and hardware of the source allows you to adapt the modes to different conditions of ignition of the arc, assembly of the joint, the positions of the torch, etc.
As mentioned above, the most advanced sources with synergistic controls provide welders with a simplified interface that reduces the time of personnel training.
Advantages of Pulse Welding
The use of pulsed welding technology in a shielding gas atmosphere in combination with synergistic control leads to:
- Serious savings in welding consumables and shielding gas – the range of applicability of welding wire of each specific diameter is significantly expanded.
- For example, if earlier in the warehouse it was necessary to have a number of welding wires, with diameters of 0.8; 1.2 and 1.6 mm, then when switching to modern welding technology, this entire series can be replaced with a wire of one diameter of 1.2 mm. Thus, the cost of purchasing wire is reduced, the need for storage space is reduced and, very importantly, there is no need to reconfigure the wire feeder in connection with the installation of a wire of a different diameter.
- Reducing the required range of accessories – burners, tips, etc.
- Significantly less splashing and smoke generation. Reducing spatter also leads to savings in welding materials, since most of the molten wire is involved in the formation of the weld. The time required to clean welded parts and technological equipment from splashes of frozen metal is reduced. Reduced smoke generation helps to improve the working conditions of the welder, reducing fatigue and improving the quality of work.
- Less distortion of the shape of the welded parts by reducing the heat input, which improves the overall quality and appearance of the seam.
- Reduced time and cost of auxiliary operations and finishing of the welded joint. These advantages are of particular importance when welding stainless steel, nickel-containing alloys and other materials, the characteristics of which deteriorate with excessive heat injection.
- Increase the productivity of work, because the degree of surfacing is higher.