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TIG WELDING

Contaminated Tungsten Electrode

• That air does not enter into the gas

The tungsten electrode may be contaminated through contact with the molten pool or the filler metal rod.

• That wind or draft does not blow

It will also be contaminated (by oxidation) if the shielding gas supply is not opened before the arc is struck, or if the gas is shut off before the electrode has cooled down to below red glowing temperature.

hose.

away the shielding gas.

• That the argon supply is not

contaminated (try changing to fresh cylinder).

If there is little contamination the electrode may be cleaned by striking an arc against a copper plate and letting it burn for a few seconds. Remember gas supply.

If the electrode is heavily contaminated the welding current supply must be disconnected, the electrode removed and the contaminated part broken off. The electrode must be reground to the correct point and replaced in the torch.

Contaminated Weld Pool

Clean the electrode by striking an arc against a copper plate.

This can be caused by insufficient or excessive supply of argon to the torch, by polluted argon, by insufficient cleaning of the weld area or of the filler rod, or by the electrode being polluted.

Check the following:

• That the gas hose has been properly purged.

• That the gas flow has been correctly set.

• That the electrode is held at the correct angle.

• That the gas nozzle is not defective or polluted.

• That the correct size gas nozzle is being used.

• That welding groove and filler rod are clean.

4.02

Strong draft may blow away the argon shield, resulting in contaminated weld deposit.

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