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7. Possible Welding Deficiencies
The following deficiencies are related to situations outside the the electronic circuits
and are mostly attributed to accessories, gas and power supply and external
circumstances. These can be circumvented by controlling the environmental factors.
7.1. Blackened Welding Spots
This phenomenon indicates that the welding spot is oxidised owing to insufficient
protection. The following remedial actions can be pursued.
7.1.1. Check the efficiency of Argon gas flow and pressure. As a general rule the
pressure in the cylinder should be above 0.5 mPa. If not, exchange or refill
the cylinder.
7.1.2. Check the Argon gas-flow meter. Ensure the correct flow-rate for the job at
hand and, in any case, should not be below 3l/min.
7.1.3. Ensure that the gas flow through the torch is unobstructed.
7.1.4. Ensure that the gas is of good quality.
7.1.5. Strong air flow in the welding environment may influence cover-gas
efficiency.
7.2. Difficult Arc Start or Easy Arc Break
7.2.1. Only use a good quality tungsten electrode.
7.2.2. Tungsten electrodes that have not been sharpen processed are less likely to
perform successful arc start and can cause arc instability.
7.3. The Output Current is Below the Rated Value
Power supply which deviates from the rated value, will have a consequential effect
on the maximum and set-current output value at the torch end. Under-power input
will result in under-power output.
7.4. Unstable Output Current During the Welding Operation.
Grid-voltage changes and interference from other electrical equipment can have an
influence on current output.
7.5. Excessive Burn-up of the Tungsten Electrode.
The distance between electron emission from the workpiece and the electrode is too