Use Of Inert Gases In Tig And Mig

If the work materials are not stainless steel or higher alloys, the weld joints will inevitably corrode.

The inert gas sheilds purpose is to reduce burning (oxidizing) of the object metal to be welded and the filler metal (wire or rod). Notice if you have no gas the recation of the arcing is more violent (you will have more splater as well). As a note all metals oxidize, it is only a question of how there oxide is formed i.e. chormium has an oxide layer that is impervious, so further oxidation will not occur unless it is damaged; the iron in steel on the over hand has a pervious oxide layer so further oxidizing will occur.

So as the previous comment stated it depends on your materials object metal and filler metal as to what level of oxidzing will occur after welding.

The same is true for MMA (stick) welding, where the electrode coating provides the gas shield as it burns.

inert gases are used during tig and mig welding because under inert atmosphere to prevent oxidisation of metels at high tempreature (as the metels chemical and physical propertis change under deffiernt atmospheric conditions and temperatures).and achive strong metel to metel bobnding,if the same metels are welded under normal atmospheric conditions the welds will fail and the purpose of welding itself defeated. well corrosion is defferent process al tugether and needs seperate discussion

guest

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The Noble Inert Gases:

www.chem4kids.com/files/elem_inertgas.html

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Re: Use Of Inert Gases In Tig And Mig

should read Use of inert shielding gases in tig and mig welding processes

The importance of the word "shield" is my answer to your question. Choosing a gas or mixture is what you should try to understand. Choose your metal and then your shield. Try to visualize the shield as an umbrella over the weld area. It is put there to replace air therefore the word shield. It is put there to provide an area for the vaporized or molten filler transfer.

.y

THATS CORRECT, THE SHIELDING ONLY PROTECTS THE MOLTEN WELD POOL DURING WELDING AND COOLING,

ALLOYING ELEMENTS IN YOUR FILLER METAL, YOUR MATERIAL CHOICE AND YOUR WELD PROCEDURE WILL ALSO REDUCE OR PREVENT CORROSION AFTER WELDING.

It sounds like you need to be looking at your post fabrication surface preparation and coating requirements along with a maintenance program appropriate to the coating and environmental exposure.

These shielding gases are intended only to prevent oxidization during the weld, not afterwords. In aluminum welding, especially, these oxides can form so fast that the weld metal will not flow together, unless the shielding gas is there. After the weld is completed, then you must take steps to prevent corrosion appropriate for the alloy of the base metal and weld metal.

Oddly enough, with aluminium it is the oxide coating that normally forms quickly on the metal that prevents corrosion.

The very purpose of inert gases used in the welding processes you mention is to produce sound welds by preventing oxidation mostly.What happens to the weld subsequently is not part of it and it has to be handled separately.