By its very nature, TIG welding is a relatively slow process. But it is also a very versatile one. In fact, it can be used to weld more materials than any other welding process, even exotic and heavier alloyed metals. It’s also well suited for thin materials, as it generates a low heat input to prevent burn-through. No matter the application, when done properly, TIG welding can provide extremely high weld quality.
Achieving such positive results, however, isn’t always easy — it’s as much a matter of training and practice as it is simple patience. Fortunately, arming yourself with a few tips along the way can help you greatly improve the efficiency of the process.
Invert the process
Using an inverter power source is one of the first steps you can take to improve TIG welding efficiency. Inverters operate by switching high-voltage low-amperage alternating current (AC) into direct current (DC) back and forth at a very high rate of speed — up to 50,000 times/second. The overall result is a smooth arc that provides consistent welding performance.
Inverters also have frequency controls that allow you 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 adjust the frequency from 20 Hz - 400 Hz. (Note: Transformer-based power sources only produce an output of 60 Hz, which is the same frequency that comes from the wall power receptacle).
The inverter’s frequency feature helps improve your welding efficiency by narrowing the focus of the arc, which, in turn, creates a narrower weld bead and minimizes the heat-affected zone. With this feature, you will need less time and filler metal to complete the weld and can also obtain faster travel speeds. By reducing the heat-affected zone, you can minimize the chance of burn-through and the need for rework.
Inverters also feature a balance control, which allows you to adjust how long the current spends in each part of the AC cycle and is especially useful if you are welding aluminum. You can adjust the balance control toward the electrode positive part of the cycle to gain more cleaning action (removal of the oxide layer) or toward the electrode negative to gain greater weld penetration and faster travel speeds that allow you to finish the job sooner.
Stay cool and flexible
Selecting the right TIG torch for your application can also help make the process more efficient. First, select a torch with good insulation. Silicon rubber insulation, for example, protects against high frequency leakage and/or cracking that may lead to premature torch failure and downtime for torch changeover.
Also, determine whether you need an air- or water-cooled TIG torch. Air-cooled models can be used on low amperage applications, or those below 200 amps. They are the best option if you are welding very thin materials, under 3/16 inch, and/or need to be able to move from one area to another easily, as they do not require an external cooler. You should consider a water-cooled TIG torch for applications over 200 amps. This type of torch helps prevent overheating and allows you to achieve faster travel speeds — both factors that let you put down more weld metal in less time.
When selecting a TIG torch, also consider the angles that you need to weld since maneuvering around difficult joints can be time consuming, not to mention uncomfortable. Most TIG torch manufacturers offer models with flexible necks that are good for welding in particularly tight joints or awkward positions. Some torch body styles also feature a modular design, which allows you 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.
The photo on the left shows the even shielding gas flow a gas lens provides compared to a TIG torch without a gas lens (right).
When possible, use a gas lens. A gas lens replaces the collet body in a TIG torch to help hold the tungsten in place and creates the electrical contact necessary for proper current transfer. It also provides two other functions that can help you improve your efficiency: it improves shielding gas coverage and provides you with better joint accessibility.
Gas lenses are typically comprised of a copper and/or brass body that contain layered mesh stainless steel screens. These screens distribute the shielding gas evenly around the tungsten and along the weld puddle and arc to help prevent oxygen contamination that could lead to weld defects. As in any welding application, lowering defects and their associated rework ensures you can spend more time welding and increasing your productivity.
Gas lenses also allow you to extend the tungsten electrode further out from the nozzle. This additional electrode extension provides better visibility of the joint and arc, allowing you to have greater torch control and achieve better weld quality especially on critical applications and/or hard-to-reach areas such as “T”, “K” and “Y” joints.
Gas lenses are particularly helpful when TIG welding on alloys that are highly reactive to atmospheric contaminants or on materials used in high temperature applications. They can also be used with all types shielding gases and are available for both air- and water-cooled TIG torches.