Most companies have the highest quality requirements for their weld seams, but they also could benefit from a solution that is fast, simple and above all, cost-effective. When welding, it’s not only seam quality that matters; speed plays a significant role, as well.
Both of these allow the welder to work more efficiently, and when a welder is working to the best of his – and the equipment’s – ability, costs are ultimately reduced. But in some cases, even the best welder and equipment cannot make up for the issues inherent to a specific process, such as TIG welding.
With that in mind, Fronius developed an innovative take on the traditional TIG process – one that addresses the seam quality and speed of mechanized joint welding. Referred to as ArcTig, the new approach involves a special welding torch that allows the TIG arc to be focused in a targeted manner and its energy density to be significantly increased.
When employing the modified TIG process, welders can weld up to 10-mm-thick, high-alloy sheets and pipes without extensive seam preparation. And they’re able to do it to an exceptionally high-quality standard and much quicker.
Process principles
Fronius’ ArcTig welding process is based on the principle of tungsten inert gas welding, known to most as TIG welding. Well suited for a variety of materials and applications, TIG welding can also tackle the joining of tricky materials like titanium.
During the TIG process, an arc burns between a non-melting tungsten electrode and the metallic workpiece in an oxygen-free, reactionless gas atmosphere. The current flow heats the electrode, resulting in an electron flow. This reduces the combined resistance, producing a soft, wide arc.
Additionally, the inert protective gas shield means there are no chemical reactions with the liquid weld pool. This enables welders to produce a perfect weld seam appearance with the best weave pattern – and all without tempering colors and spatter.
While the ArcTig welding process is able to deliver on TIG welding’s main capabilities, it’s been specifically designed for applications in container and pipeline construction, in the manufacture of turbines and the construction of special machines, cranes and tanks.
The key innovation with the ArcTig process is the optimized welding torch, which features an electrode clamping system. This clamping system enables the electrode to be cooled right to the tip, increases the combined resistance and creates a high arc voltage.
In this setup, electron emission now takes place over a small area, but at an extremely high density. This makes the arc narrower and more targeted, allowing the welder to achieve exceptional weld seam quality. Another advantage of the cooling is that it prevents overheating of the electrode during welding, providing increased arc stability and ensuring a longer service life and improved ignition.
A leg up
The quality afforded by the ArcTig process provides fabricators with a major leg up in terms of customer satisfaction, but in today’s competitive landscape, speed is also a must. Without quick processing times, fabricators can’t deliver on the ever-shrinking turnaround times demanded by customers.
Addressing those concerns, the focused and high-pressure arc means the ArcTig can be used to weld components in one layer to a material thickness of up to 10 mm. In conventional TIG welding, several layers are often needed. This upgrade on its own reduces the time it takes to lay down a quality weld.
Additionally, it is frequently the case that users no longer need to do time-consuming preparation work on parts. As there is no gap during seam preparation, no weld pool support is required for the ArcTig process. This cuts down on rework to a large extent since the weld seam is raised to a minimal degree and there is very little distortion due to the reduced heat input.
This enables users to accelerate processing times considerably while the welding process also permits higher welding speeds. Beyond the time and quality delivered by the ArcTig process, material costs are lowered as the weld seam volume is reduced.
Furthermore, the process also impresses in terms of operation. Because it is very similar to TIG welding, users do not have to adjust to a new process and can weld immediately without carrying out any time-consuming training period.
Minimum needs
Minimizing the need for training and preventing incorrect operations by the welder, just a few parameters need to be set. Additionally, welders can make use of standard TIG electrodes that are quick to change and easy to be reground, as necessary.
The new electrode clamping system clamps the electrode over a large area. To make the weld seam more accessible and enable the arc to be manipulated better, the free end of the electrode can be adjusted as desired depending on the requirements.
Users can upgrade all TIG power sources from Fronius above an output of 400 amps to the ArcTig process with ease. The only equipment required is the new welding torch and an additional heat exchanger to provide the cooling capacity and the required temperature stability. ArcTig is also available as a complete system.
