Whether it’s manual welding, automated or orbital welding with an open head, the procedure of TIG welding comes with certain risks for the welder that have to be met with precaution, especially those that are not necessarily visible at first glance.
The necessity of protecting your eyes when TIG welding
Any welder who has ever welded with the manual TIG process is familiar with "arcing". When the electric arc builds up, it produces intense ultraviolet (UV) and infrared (IR) radiation. This is caused by the arc itself and the change in temperature of the base metal – steel causes the arc to glow red. These two types of radiation are not visible to the human eye, but this in no way diminishes their effect on the human retina.
Additional to these types of radiation, there also is the visible light emitted by the arc and the melt bath. If the welder isn’t properly protected, this radiation can entail risks of temporary or permanent eye damage.
To shield himself against these visible and non-visible types of radiation, it is indispensable for a welder to use a welding hood with glasses that for one part reduce the visible luminosity and for the other filter ultraviolet and infrared radiation.
The filter glass needs to be chosen according to the welding intensity, thus conform to the ISO 4007 standard. For intensities ranging from 10A to 300A, the index of the filter glass varies between 8 and 13. The higher the index, the darker the glass.
For TIG welding, one also needs to pay attention to the types of materials that are to be welded. If the surface is mirror polished for example, the arc can be reflected off of the surface which makes it just as dangerous as if it was directly looked at.
Last but not least, a welder usually works in a workshop with various other actions happening around him. In order to not disturb and endanger the people working in the same room, it is advised to “fence” the welding area with radiation-filtering curtains.
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Protect your skin against the effects of radiation when welding with TIG
Direct ultraviolet (UV) radiation has the same impact on you as exposure to the sun, but its effects on your skin appear much faster and after a shorter time of exposure.
Even a very short period of exposure can cause redness that will get even worse if the welding intensity and exposure time increase.
In order to avoid this problem when welding, the only solution is to cover up your entire body with a coverall. This includes a welding hood and gloves that shield you against radiation but also against the heat generated in the vicinity of the arc.
Electrical risks when welding with TIG
The use of an electrical welding machine poses electrical hazards if basic precautions are not taken.
First of all, the electric network to which the power supply is connected needs to be well grounded. Welding power supplies are generally enclosed in metal containers, so if a leakage current builds up, it needs to be directed into the ground immediately. Also, in case this happens, the welder needs to be equipped with insulating safety shoes.
Next, it needs to be checked that the welding equipment is in good condition and that the electrical cords are not stripped.
It should be noted that nowadays, arcing is carried out through high frequency ignition. A high current is sent back and forth between the electrode and the material at a very high frequency in order to create a non-contact electric arc. This avoids tungsten inclusions in the weld pool, but might disrupt nearby electrical devices, such as pacemakers for example. For this reason, high frequency ignition welding is prohibited in the medical environment.
Risks related to gas when welding with the TIG procedure
When the procedure of TIG welding is applied, it is vital to use a gas to facilitate the arc initiation, but also to protect the weld pool. The gas most often used when welding with TIG is the inert gas argon.
Argon has properties that make it particularly attractive for welding, but it also poses great danger in certain situations when for example the welder is required to weld in a confined area, such as a tank.
Argon is an odorless and colorless gas heavier than air. A welder working in a tank cannot see the argon, which gradually fills up the space and displaces the oxygen. When the amount of oxygen drops too low, the welder suffers from a loss of coordination, headaches, nausea and eventually hypoxia.
Generally speaking, when this kind of welding configuration is unavoidable, drastic safety measures need to be imposed. The welder must carry an indicator that warns him when the oxygen level in the air is too low, he must have a fresh air supply and he also needs to wear a safety harness connected to a winch that is controlled by a second person. This person must have a visual of the welder and be in communication with him to pull him up in case the situation requires it.
The importance of a good evacuation of fumes and dust when TIG welding
When considering fumes and dust, the procedure of TIG welding is very interesting because it is the type of welding procedure that produces by far the least amount of fumes and dust. However, the fumes produced are no less dangerous.
The fumes are created in the process of decomposing argon in the arc, which creates ozone (O3) and nitro dioxide (NO2 or else NOx) when nitrogen is involved.
As far as dust goes, it generally results from the volatilization of the elements composing the base metal and/or the filler metal in the form of fine particles.
To evacuate the fumes and dust, it is important to install a general ventilation system in the workshop that is connected to a localized extraction with an extractor hood and an articulated arm.
These simple but nonetheless crucial pieces of advice for safe welding with TIG should be known by all welders.
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