5 Fundamental Rules To Correctly Perform TIG Welding

This method has become one of the most widespread and productive, but it is also the most complex one because it must be carried out according to very specific rules.

The TIG welding method was developed during the Second World War for military purposes, and is currently one of the most used processes. Arc welding with infusible tungsten electrode under inert gas protection, commonly known by the abbreviation TIG (Tungsten Inert Gas) is a more complex process than normal manual MMA coated electrode welding, and requires good experience and coordination to ensure satisfying results.

The advantage of this particular process, however, is that of providing high quality joints with a high degree of tightness; Furthermore, TIG welding is also characterized by high productivity and the possibility of being used on different types of metal alloys, including those of aluminum, magnesium and titanium.

These characteristics have ensured that the TIG methodology spread extremely quickly at all levels, especially in the hobby and artisan field, despite its difficulty of execution. In fact, among the different versions available on the market, the best-selling TIG welding machine is precisely the one with medium-low power, and this is enough to give a general idea of ​​how much the hobby and artisan user range that makes use of this has expanded. particular type of plant.

The conditions and cleanliness of the working environment

Returning to the subject of the complexity of the method, this arises from the particular conditions required for its correct execution; in fact, to ensure high quality and tight joints, the weld pool must first of all be isolated from the surrounding atmosphere in order to prevent contamination from slag and oxidation due to contact with oxygen.

Consequently, the work environment where TIG welding is performed must be kept clean, and the same applies to the operator’s equipment, especially gloves and protective helmet given their proximity to the welding pool.

Furthermore, as far as possible, it is advisable to shield the welding area from air currents, which could easily blow away the inert gas intended to protect the bath, with the risk of contaminating the molten metal and irremediably compromising the quality. welding.

The choice of the most suitable gas

To protect the weld pool, inert gas is used to create a sort of “jacket” on the point where the arc is created; the type of gas to be used varies according to the temperature, and consequently to the type of alloy and thickness to be welded. The inert gases used for TIG welding are argon, helium and argon-helium and argon-hydrogen mixtures, which apart from their specific characteristics also differ in cost.

Argon gas, for example, is cheaper and is especially suitable for welding thin thicknesses, which is why it is especially used in the hobby field; helium is more expensive on the other hand, and being lighter than air requires its use in higher doses, but since it favors an arc with a higher temperature than that generated in argon, it is characterized by a productivity and a higher efficiency.

Correct use of gas

Once you have chosen your gas, you need to make sure you are using it correctly. Even if the new TIG torches are equipped with a specific nozzle for automatic dispensing during welding, in fact, the necessary precautions must still be taken, starting with the size of the nozzle.

This must always correspond to the diameter of the electrode, otherwise the protective jacket would end up presenting “leaks” and frustrate its primary purpose; if the electrode has to be replaced with one of a different size, the nozzle will have to be changed accordingly.

The gas outlet pressure must be adjusted appropriately; there are TIG welding systems equipped with the appropriate pressure reducer which allows to regulate the gas flow directly from the system, thus allowing the use of cylinders without a pressure circuit.

The alternative, on the other hand, is to purchase a specific pressure circuit to be applied to the cylinder, so that it can be used safely with welding systems without a reducer. Apart from this last component, the pressure circuit must also have a pressure gauge and a solenoid valve, which once connected to the torch will allow the gas flow to be opened and closed directly from it and according to the operator’s needs.

The importance of “keeping the right distances”

It almost seems like a joke, but another very important aspect to pay attention to in order to guarantee the perfect success of a TIG welding, is the right distance to be kept between the arc and the piece to be welded.

There are two reasons, the first is related to the temperature: in fact, any variations in the arc distance, even minimal, generate variations in the temperature of the bath which result in a non-homogeneous bead. The second relates to the consequences of any contact of the electrode with the piece to be welded, with consequent “sticking” or release of slag in the weld pool which compromise the quality and tightness of the joint.

This is why the TIG welding process is more complex and requires considerable dexterity and experience to guarantee the best results, especially in cases where the use of filler rods is required.

Coordination in movement

To perform a good TIG welding, therefore, it is necessary to develop a good coordination of movement. This is especially required when it is necessary to weld thicknesses greater than three millimeters because in these cases the use of filler rods is required, as previously mentioned.

In this case, in fact, the operator is forced to use both hands, one to use the torch and the other to bring the rod near the welding arc; if you add to this the need to always keep both the distance of the arc and the movement of advancement along the seam line constant, you can easily imagine the degree of expertise required to obtain perfect welds.

These “rules” must not at all discourage novice welders, of course, on the contrary they want to be a stimulus in practicing, performing as many “training” welds as possible before tackling more demanding jobs.

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