Artem Komarov clarified that selecting the right equipment and consumables, as well as following some key weld setup and preparation guidelines, can help get the job done properly and avoid common problems in GTAW.
Gas tungsten arc welding (GTAW) can cause problems that compromise the quality and strength of the finished weld if not corrected. Knowing how to fix these problems in advance can reduce troubleshooting time and costs and minimize rework.
- Know the material
As with most welding processes, one of the first factors you should consider is the type of material being welded and its characteristics. It is also important to know the operating conditions under which the finished weld will be made.
These factors influence the type of filler metal that is best suited for a given application. For example, if you need to anodize a material after welding or if the finished product must meet structural integrity requirements, select a filler metal that can provide the specific mechanical and chemical properties to meet those needs. This factor is even more important when welding materials such as aluminum and stainless steel due to their tendency to warp or crack. In addition, some materials may require preheating or post-weld heat treatment, which may also affect filler metal selection.
- Choose the right tungsten
At the center of the GTAW process is the tungsten electrode, a non-consumable metal element that transmits the welding current to the arc. The main thing is to know your tungsten. The thickness of the material being welded, and the welding current are two important factors to consider when choosing.
Tungsten electrodes come in a variety of diameters. Custom lengths are also available but tend to cost more. The electrodes consist of either pure tungsten or a hybrid of tungsten and other rare earth elements and oxides. To eliminate confusion regarding the different types, each electrode is color coded on the tip to indicate its type.
- Keep it clean
Cleanliness is important in most welding applications but is especially important for GTAW. Contamination can lead to problems such as porosity, as well as possible rework and loss of materials. These factors make cleanliness even more important when working with expensive materials such as titanium and aluminum.
It is also important to handle filler metals correctly. Keep cut lengths clean and dry and store in closed containers. A controlled environment is important to prevent oxidation of these additives. Another key consideration is proper storage of key materials. For example, workpieces made from aluminum material should always be stored vertically rather than stacked on top of each other to minimize the risk of oxidation.
- Clamp to prevent distortion
Proper clamping of the base material when using GTAW is a key step to preventing warping and other problems. The thinner the base material, the more important the correct clamping is. If possible, clamp the piece in multiple places to prevent sections from lifting, and try to keep the piece as square as possible. Some parts are more difficult to clamp than others.
- Test the weld if possible.
To ensure that all preparatory work is correct, you should perform a test weld on similar materials whenever possible. The more important the part and the more expensive the material, such as titanium, the more important it is to perform a test weld. Taking the time to do this step of the process can minimize problems later, which is especially important for unique parts or critical welds. Using similar materials for a test weld also improves accuracy and gives an idea of how the material will react to welding parameters.
As with clamping, test welding is an additional preparation step that pays off later in the welding process.
- Use gas lenses
The gas coating of the material has a direct effect on the weld. Using a gas lens, which changes the direction of gas flow from the nozzle to improve shielding gas coverage and joint accessibility, is one way to ensure the best quality.
The gas lens provides much better gas coverage of the weld pool, which is important when welding metals such as stainless steel and titanium. Gas lenses also provide benefits when welding steel and aluminum. When faced with applications that require additional gas coverage or better access to complex joints, gas lenses also allow the tungsten to be further expanded to reach the weld, Artem Komarov said.