NITROGEN & Welding!

[@leebatt7964]

Nitrogen is an inert gas and it has the same ionization potential as argon. It can be used in certain tig applications as a backing gas. Its widely used in gas brazing. Its mainly O2 that causes problems. All shielding gasses are used to displace oxygen and prevent oxidization of the metals. However, Nitrogen should not he used with certain stainless alloys in critical welds, cryo and high pressure for example.

[@drodriguez394]

I have to challenge that. In HVAC we use nitrogen as a shielding gas while brazing

[@Amerikanin2numarali_ustasi]

you dont ...u use nitrogen to prevent oxidation in the copper pipe

[@CompanyofHeroes999]

Yes, with Cu alloys Ni and Ar - Ni mixtures are used. But that's with copper. It depends on the material. While nitrogen is relatively inert, it still does difuse into melted steel and causes problems. With Cu is different.

[@fijimenu]

You use shielding gas to keep out oxygen so there’s no oxidation

[@williamtitus8467]

Both oxygen and nitrogen exist as diatomic molecules at standard temperature and pressure. These atoms bond to one another with covalent bonds that are dependent upon how many electrons are in the outer shell of the atom. Nitrogen, for instance, bonds to another Nitrogen atom with three covalent bonds. These three bonds securely bond the two nitrogen atoms--so much so, it makes the Nitrogen atom unavailable for making bonds with other atoms--making it a somewhat inert gas. Oxygen, however, is bonded to another oxygen atom with just two covalent bonds. Another diatomic molecule is hydrogen--which bonds to another hydrogen atom with just one covalent bond. In an environment with limited opportunity to react with other material (such as in open air) it will exist as this diatomic molecule. However, given some energy (a spark, and arc or a flame) the diatomic oxygen will break apart and violently react with many materials--especially hydrocarbons, and yes, metals. Iron oxide is a common bi-product of iron and oxygen since in the presence of water vapor, oxygen can readily combine with elemental iron. Likewise, during the act of welding, where huge amounts of energy is being applied, oxides of oxygen--including iron oxide is formed. The inclusion of the oxides into the molten pool weakens the weld. Diatomic Nitrogen can also be torn apart with high energy, but much less so because of its 3 bonds. It is considered inert at standard temperature and pressure, but during welding, temperatures are far from standard, and thus, it to can form nitrogen by-products that can also weaken welds. By far, oxygen's high reactivity and weaker diatomic bonds make it the biggest culprit. This is why diatomic hydrogen is so explosive--its one covelent bond is easily broken and it can violently react with oxygen--forming water. (think Hindenburg) With true noble gases, such as neon, argon and helium, the outer shell of the atom is full. There are no extra electrons unpaired and available for reaction with other atoms. Thus, these cases, when flooded over a weld, shield the molten pool of metal from reacting with atmospheric gases and cannot themselves react. Diatomic Oxygen is so reactive, that just having a hydrocarbon lubricant in an oxygen line can cause problems. The same is not true for nitrogen lines. During respiration, diatomic oxygen readily reacts with carbon waste in the alveoli of the lungs and creates CO2, which we exhale as a waste gas. Nitrogen is also breathed in and expired, but it is exhaled unchanged due to its inert nature.

[@JWG2014]

This miss information.. Nitrogen is not the issue.. Oxygen does the oxidation. That's why you don't tig with CO2..

[@shailendrasharma5432]

We prepare weld pad by tig welding process of stainless steel grade ER308L 1.60mm with sheilding gas Argon 99.98% for chemical composition analysis. Nitrogen pickup shown in chemical analysis Example in heat actual value is N=820ppm In tig welding weld pad value is N=1600 ppm What is the reason?

[@whatevernamegoeshere3644]

Oxygen is within a shielding gas, yes. Just like how chlorine gas is in table salt lmao.

[@MrTravis789]

If you don't know for sure, just take a guess😅

[@bullitlbc]

Can you do a more comprehensive video on the cwi exam

[@AutismusPrime69]

Did you even do your research on this? Nitrogen is inert

[@NewZealandPakeha]

I think I'll try hook my nitrogen onto my mig

[@davebennett9358]

Doesn't work good with dual shield nothing but porosity

[@andrewwitcher7432]

I've heard that it can be used as a back purge gas

[@mikethecripple]

Andrew Witcher yea I was wondering that too, I use it as a v Back purge on stainless, I'm guessing this is relating 99% to mig welding

[@kf8575]

Have quite a few times used Nitrogen as a purge gas for welding duplex and super-duplex pipe. With heavier sections, used argon with 2.5%(if i remember rightly) hydrogen added to the gas. The H2 scavenges any oxygen from the oxides within and around the pool giving a very very clean weld. Also it gives a hotter arc, allowing faster travel speeds, therefore lower overall heat input.

[@risby2]

thanks

[@NewZealandPakeha]

0.039% Shut down all oil immediately. Starve and destroy your economy.

[@whatevernamegoeshere3644]

Just gonna point it out that it impacts mental skills decently badly already at 1% and it's lethal within minutes at 8%. The pH of the ocean is also a balancing act and 0,04% is pretty significantly acidic when dissolved in water (without buffer it would be at about pH=5).

[@jeffhulett4194]

Good information, good explanation, you should get a lapel microphone so we can hear you better.