Tips for Improving Gas-Tungsten-Arc-Welding ProductivityMarch 1, 2010
By its very nature, gas-tungsten-arc welding (GTAW) is a
Achieving such positive results, however, isn’t als easy—success is as much a matter of training and practice as it is simple patience. Fortunately, arming yourself with a few tips along the can help you greatly improve the effectiveness of the process. After all, you don’t want an already slow welding process to become even slower.Tip #1: Invert the Process
Using an inverter power source is one of the first steps a metalformer can take to improve GTAW efficiency. Inverters operate by switching high-voltage low-amperage alternating current (AC) into direct current (DC) back and forth at a very high
Inverters also have frequency controls that allow the welder to determine the length of time that it takes the unit to complete one full current cycle (the combined time spent on electrode positive and electrode negative), and to adjust the frequency from 20 to 400 Hz. (Note: transformer-based power sources only produce an output of 60 Hz, the same frequency that comes from a wall power receptacle).
The inverter’s frequency feature helps improve welding efficiency by narrowing the focus of the arc, creating a narrow weld bead and minimal heat-affected zone (HAZ). With this feature, welders will spend less time and consume less filler metal completing each weld. And, a smaller HAZ minimizes the likelihood of burnthrough and the need for rework—a definite cost saver in any welding application.Inverters also feature a balance control, which allows the welder to adjust how long the current spends in each part of the AC cycle—particularly useful when welding aluminum. He can adjust the balance control more toward the electrode-positive portion of the cycle, which helps to remove the oxide layer on the aluminum workpiece (referred to as “cleaning action”), or more toward the electrode-negative portion of the cycle, which increases weld penetration and travel speed.
Tip #2: Stay Cool and Flexible
Selecting the right GTAW torch for the application also can help make the process more efficient. First, select a torch with good insulation. Silicon-rubber insulation, for example, protects against high-frequency leakage and cracking that can lead to premature torch failure and downtime for torch changeover.
Also consider whether an air- or water-cooled GTAW torch is best suited to the application. Air-cooled models prove useful for low-amperage applications, below 200 A, for welding materials less than 3⁄16 in. thick, or for shops where welders tend to move around a lot, since these torches do not require an external cooler. Conversely, consider a water-cooled GTAW torch for applications in excess of 200 A. These torches help prevent overheating and allow welders to achieve faster travel speeds.
When selecting a GTAW torch, also consider the angles at which the welders must weld, since maneuvering around difficult joints can be time-consuming, not to mention uncomfortable. Most GTAW-torch manufacturers offer models with flexible necks that make the job easier in awkward positions.
Some torch-body styles also feature a modular design, which allows the welder to add a flexible neck and different head angles to an existing torch. These kits provide good joint access and can lower downtime associated with changing over different torches for multiple applications. Plus, you can save money on extra inventory.