helium for tig welding

[Bradspecialties]

Can anyone tell me some pros and cons of using helium as sheild gas for tig welding aluminum. What is better weld quailityand penitration , helium and argon mix or should i use straight helium? Any input would be greatly appreciated.

[griff01]

Can anyone tell me some pros and cons of using helium as sheild gas for tig welding aluminum. What is better weld quailityand penitration , helium and argon mix or should i use straight helium? Any input would be greatly appreciated.

I have never used straight helium but have used argon/helium mix. The mix is HOT.

It would be helpful to know what thickness material you are using


Griff

[nocheepgas]

Hijack

Not to hijack the thread, but I just ordered a sheet of 16 gauge 304 stainless, and I happen to have a bottle of helium lying around that my LWS guy gave me. Is it acceptable to use helium to back gas on stainless?

[Craig in Denver]

Helium brings more heat to the puddle than argon; at the same amp setting. If your TIG has the amps to weld your piece, helium just costs more. Note: helium is lighter than air, so if you're welding overhead, helium will rise to the puddle without increasing your CFH.

[FATFAB]

After the discovery of the electric arc in 1800 by Humphry Davy, arc welding developed slowly. C. L. Coffin had the idea of welding in an inert gas atmosphere in 1890, but even in the early 1900s, welding non-ferrous materials like aluminum and magnesium remained difficult, because these metals reacted rapidly with the air, resulting in porous and dross-filled welds.[2] Processes using flux covered electrodes did not satisfactorily protect the weld area from contamination. To solve the problem, bottled inert gases were used in the beginning of the 1930s. A few years later, a direct current, gas-shielded welding process emerged in the aircraft industry for welding magnesium.

This process was perfected in 1941, and became known as heliarc or tungsten inert gas welding, because it utilized a tungsten electrode and helium as a shielding gas. Initially, the electrode overheated quickly, and in spite of tungsten's high melting temperature, particles of tungsten were transferred to the weld. To address this problem, the polarity of the electrode was changed from positive to negative, but this made it unsuitable for welding many non-ferrous materials. Finally, the development of alternating current units made it possible to stabilize the arc and produce high quality aluminum and magnesium welds.[3]

Developments continued during the following decades. Linde Air Products developed water-cooled torches that helped to prevent overheating when welding with high currents.[4] Additionally, during the 1950s, as the process continued to gain popularity, some users turned to carbon dioxide as an alternative to the more expensive welding atmospheres consisting of argon and helium. However, this proved unacceptable for welding aluminum and magnesium because it reduced weld quality, and as a result, it is rarely used with GTAW today.

In 1953, a new process based on GTAW was developed, called plasma arc welding. It affords greater control and improves weld quality by using a nozzle to focus the electric arc, but is largely limited to automated systems, whereas GTAW remains primarily a manual, hand-held method.[5] Development within the GTAW process has continued as well, and today a number of variations exist. Among the most popular are the pulsed-current, manual programmed, hot-wire, dabber, and increased penetration GTAW methods.[6]


I never heard of "tig" welding till the mid 1980's, I first learned heliarc welding from my dad in the 1970's. First he taught me braising, then came heliarc and stick.

I never had argon till I went to work as a tig welder for the Chicago Telephone Company in 1983, up to that point all I had ever used was helium.

[Miller Brad]

Like everyone has said to this point in the thread, Helium will make the arc much hotter and will increase penetration. Cost is a major downside, but another down side is the effect that additions to Helium will have on the ability to successfully start an arc. The more Helium you have in your mix, the more problems you will have with arc starts.

[Powerstroked]

Is there any advantage in using a 75% argon/25% helium mix while welding aluminum? My first welding job that is what we used and I'm wondering why since it was said that helium is more expensive. Does it make for a better weld on aluminum?

[Wheelchair]

We at one time used it exclusively on Aluminum and as mentioned it gives a hotter puddle. We stopped using it because of the huge amount of aluminum we were welding on the deck houses on navy frigates it was getting to be very expensive. We used it not only on tig but on mig and shortarc welding also. I am retired now but a welding engineer that I have lunch with once a week said it is used very little in the shipyard now. I was taught with helium,
although it was not my metal to weld with and I never claimed to be as proficient with aluminum as I was with other type of metals, I held my own but aluminum was not my best or favorite to weld with. I really admire some of the welds i have seen in this forum on aluminum.


Wheelchair

[SundownIII]

Brad,

Most of the helium issues have already been covered (very well in fact).

Just as an aside, and going back to your original question, a helium mix is generally used to increase the temp at the weld bead. Generally used to "enhance" or extend the capabilities of the welder. Most often used when there is a heavy mass (thick plate for instance) to be welded.

Disadvantages are:

High cost (lighter than air, 2-3 times the flow rate of argon). I've seen numbers which put the cost of using helium vs argon at about 7 times the cost of argon.

Difficult arc starts.

[Powerstroked]

That makes sense though because I was welding this aluminum cast pieces to aluminum extrusion or whatever it's called. We were making frames for furniture to go on Navy and Coast Guard ships as well as the seating for the Staten Island Ferry.

[spgtti72]

The Heli in heli-arc comes from the use of helium shield gas.

[mjc79]

Please correct me if I am wrong, but I was under the impression that 100% helium does not work very well or even at all on aluminum or magnesium. I am aware of helium/argon mixtures being used on these metals, but I heard or read somewhere that 100% helium does not allow the cleaning action to take place. Again, I could be wrong, but I thought that cleaning action can't occur without argon present. Is this true?

I have never TIG welded with anything other than 100% argon, but I have heard, as others have mentioned, that it makes the arc much hotter.

mjc.

[dseman]

Please correct me if I am wrong, but I was under the impression that 100% helium does not work very well or even at all on aluminum or magnesium. I am aware of helium/argon mixtures being used on these metals, but I heard or read somewhere that 100% helium does not allow the cleaning action to take place. Again, I could be wrong, but I thought that cleaning action can't occur without argon present. Is this true?

I have never TIG welded with anything other than 100% argon, but I have heard, as others have mentioned, that it makes the arc much hotter.

mjc.

The cleaning of the base metal occurs due to the polarity of the arc, not the shielding gas. Argon and DCEN will provide no cleaning, just as Helium and DCEN will provide no cleaning. If you plan to use AC and Helium you just need to adjust your waveform balance accordingly and you'll have no problem with cleaning (oxide removal).
-dseman

[mjc79]

What I had read, I believe it was in a welding textbook, was that cleaning action requires two factors: electrode positive polarity, and at least some argon in the arc zone. It can't occur unless both of these conditions are in place. I have also read that having helium in the mix gives a bit dirtier of a weld, and I thought that was becausr there was less cleaning action. Is that incorrect then? Thanks much!

-mjc

[Newton Brawn]

helium for tig welding

Hi !

I need some information about the Hf voltage level required to start to open a arc between the tungsten electrode and work.

Assuming that a tig welding machine have the main power current off, and no the shielding gas ( gas closed ) what is the distance between the electrode and work that the spark initiates ?

If we use helium shielding gas and keeping the main welding current off, wich distance the spark initiates ?

If we use argon shielding gas and main current off, wich distance the spark initiates??

How about CO2?

The only reference that I have is from someone playing with HF and argon suggesting that arcs in argon are about 6 times bigger than in air.

Thanks in advance of any information