TIP TIG Welding is always better quality than TIG and 100 to 500% faster with superior quality than TIG - MIG - FCAW.

• Return to Mig Welding Gases Part 1

MIG Gas Facts. Part 2.

ED PROVIDES SIX OPTIMUM MIG GAS MIXES FOR
ALL MIG WELDS. HOW SIMPLE LIFE CAN BE. Section 1.

AWS A5.52 is the USA Specification for MIG / TIG shielding gas mixes. Ed was on the AWS committee that wrote this gas spec. It was a struggle for him to keep the marketing hype out of this spec, I suppose as it is with any specification that's written or influenced by marketing personnel who represent specific products and have a bias or agenda they want to include.

In his product development role with AGA, Airgas and Liquid Carbonic, Ed developed four of the most popular MIG gas mixes used in North America. Extensive MIG gas selection information is available in part one . These two sections are intended to take the mystery out of the available 40 plus different MIG gas mixes.

 

 

With many MIG weld gas salesmen, we often
get too much gas and too few weld facts.

E Mail Question to Ed.
Kevin M Gough
03/03

Ed, as you know I ordered your MIG and flux cored book. I love the straight forwardness of the site and the attention to one important detail- credibility!!!!!!. I have read through most of the posts on the forum and I have yet to see any refute from a gas or equipment supplier. Not that I am naive enough to believe they would, they can't!

Question are they at it again? Here is the latest gas to get thrown at me- Hobart and BOC are currently promoting argon 95% - oxygen 5%, for use with metal cored wires. The sales men went on about such selling features - as lower voltage possible increase of travel speed, equal heat input with no loss of penetration- no spatter, no undercut or visible porosity on "mill supplied" or medium rusted plate. Especially effective on welding 16 gage galvanized material in any position.

I tried the gas mix and metal cored wires and did some destructive testing on my own. On a a rust filmed piece of 3/8 low carbon steel, type 50W, I made a tee joint- and welded it at the settings they used, 25V and 265 ipm wire speed. This produced approximately 325 amps which is what they set the machine at. You get no undercut regardless how hard you try to change the gun angle- very little spatter and very little silicon deposit on the face of the weld. Here is where things got interesting I broke the specimen- and found excess root porosity or pockets of "voids". To correct the weld problem we changed the weld travel speed to slower than we typically use. Also increasing the wire feed speed to render 350 amps or above which puts us back where we started from or further.

All the best to You and Janet.
Sincerely. KMG

 

Ed's Answer. The argon - 5% oxygen gas mix like argon - < 20% CO2 mixes, promote spray transfer, however thanks to the metal cored wires lower weld current density, and the low weld voltage required for the low energy argon oxy mix, the metal cored spray transition current is dramatically lowered.

The low energy metal cored oxygen consumables when used with spray transfer and argon oxygen on components >3/16 can cause a weld penetration profile with narrow finger or nipple at the root. The narrow finger root in the low energy spray weld solidifies very rapidly and the highly oxidizing oxygen mix can promote gas pores in that area.

The oxygen addition in any gas mix will influence the weld root fusion profile. Typically a narrow finger penetration profile is produced, influenced by the lower energy narrow plasma, lower energy.This is a limited and poor weld profile in terms of weld fusion and porosity entrapment.




The narrow finger fusion weld profile freezes rapidly trapping the oxygen gas oxide reactions, increasing the weld porosity potential. Remember a primary purpose of a gas mix is to prevent oxygen and nitrogen from entering the welds.

 

So lets see, with the oxy and metal cored combo, you have low energy spray transfer, with a low weld voltage producing a narrow fast freeze root with a nipple or finger profile. The argon oxygen mix brings to the weld a gas mix with 10 times more oxidization (porosity) potential than a the gas mix that should have been used, a 5% CO2 mix. These factors also apply when you use argon oxygen with MIG wires.

With high energy gas mixes and optimum parameters and techniques, as my process control training programs indicate, most MIG weld fusion is marginal so why anyone would want to lower weld energy is beyond me. As to the low weld undercut potential , minimal weld spatter and low silicon. Lets see we can get that with argon CO2 mixes and E70S-3 0.045 MIG wire that costs substantially less than a metal cored wire. Hobart and BOC marketing personnel want you to purchase their wire and gas mixes, these personnel and the sales reps involved should occasionally put on a welding shield and then macro the welds they produce.





Weld consumable marketing personel have in the past frequently tied together a new gas mix and cored wire combination as a sales tool for weld distributors.



If the marketing people at Hobart or BOC really understood MIG welding and arc physics and had respect for their welding customers, they would have realized the metal cored wire and argon - oxy gas combo products they were presenting will likely do more harm than good for most welds > 4 mm.

CHRYSLER AND WELD GAS IGNORANCE.

E Mail Question.

July 05.

Ed. We are just starting out on a new Chrysler project welding a galvannealed product, Galvaneal NS 6000 D series 44a. According to the Chrysler spec, we would be allowed to use a solid carbon steel ER 70S-3 MIG wire, but they require a 75 argon - 25 CO2 gas mixture for this. I think Chrysler takes the cake on this gas selection. By the way if our engineers had selected galvanized material, according to the Chrysler spec we would have been forced into using the terrible self shielded FCAW process.....Is the Chrysler weld engineer from this planet? What I also don't understand is the fact that they are specifying a coated material, and then we are still required to e-coat the part. I wonder what the reasoning is behind double coating the cradles.....I'm sure they don't even know.

Regards RG. Tier One.

Ed's Answer" there is no rationalization for any of the welding logic that comes from Corporate Chrysler. Their chief welding engineer has for more than a decade been in the wrong profession. The choice of the 75-25 gas restricts the use of spray transfer on robot carbon steel welds on parts over 0.070. This gas is also not ideal for pulsed.

As for the self shielded wire, the only reason the Chrysler corporate engineer can have on his insistance of his recommendations of the self shielded products, is the self shielded wires have cost Chrysler and it's supplies millions of dollars in lost productivity, rejects and rework So if he changes his mind on his poor recommendation his apathetic engineering peers might want to know what the hells happening.

As for the double coating, it makes no sense. What does make sense is to coat the parts after welding as the weld destroys the coating in the weld area. As I said don't look for logic when dealing with Chrysler..
Visit the self shielding flux cored section for more Chrysler weld expertise.

PS: CHECK OUT BAD WELDS SECTION FOR MORE MOTOR MADNESS

Airgas and Hobart:

E-mail from Dan. Feb 2007:

Ed I think the web site is fantastic. I ordered your Management book on MIG welding. I have just had an Airgas rep visit to our construction job site. The rep sold my weld foreman on the need to move from Argon -15% CO2 mix to their new "Gold" gas.

I believe their Gold gas mix is Argon / Helium / CO2 . We are on a large blast furnace tear down Most of the steel we will be welding will be relatively clean in the range of 1/4" - 1". I Intend to set up a side by side weld comparison using our standard 82/18 CO2. Any pointers you may add in addition to what I will find in your book would be most appreciated. Do you know what the actual component composition is of the Argon/Helium/CO2 mix? Thank You!!!!!


E Mail from Jeff Chores. 03/03

Ed I've read your Management and Engineer's guide to MIG Welding, In your book, you denounce much of the marketing behind MIG weld gas selection, particularly the tri-mixes. We MIG weld carbon steels with your Ar + 15% CO2 mix , and have good success with it. We have the gas plumbed through our shop. We buy argon and CO2 in bulk and mix our own.

Welding Design and Fabrication ran a cover story in March 03 on Airgas' new tri-mix of argon, helium and CO2, claiming the three part mix yields superior performance to Ar + 15% CO2 for steel applications. My Airgas rep has been pushing me to try this, but I keep referring him to the appropriate chapter of your book and saying no thanks. Have you tried this SteelMIX Extra? Does it really outperform Ar + 15%CO2 in 1/4" fillets on mild steel? Thanks for your help.


Ed's Reply: The Weld Design Fabrication Magazine will always have weld articles that contain bias towards one of it's advertisers products. When you read the articles, take a look at the writer's profession and who does he work for.

The helium content in that tri mix is not relevant because helium is necessary for your application. It's not necessary in 2008 and it was not necessary in 1968 when I first carried out MIG gas evaluations. Dan your weld foreman like many is looking for a crutch to assist him with his lack of process expertise. If the time he spent talking to that salesman was spent at this web site, he would not need to talk to a salesman.

Many years ago, I provided the president of Airgas with the first honest MIG gas campaign presented in North America, one of those gas mixes was SteelMix. In contrast to Praxair, Air Liquide, BOC and Carbonic, Airgas became the first large North American gas company to tell the truth about gas mixes. As a result of the no BS approach, Airgas had the countries most successful and most profitable MIG gas campaign.

Why today does Airgas, the largest weld equipment / consumable supplier in the US want to promote a three part gas mix containing helium, for steel welds that do not require a three part mix? Who knows, perhaps it's simply a new marketing campaign, perhaps it's simply weld process ignorance or perhaps Airgas has an abundant supply of helium they would like to sell.

It's a shame when gas companies and distributors add to the MIG weld process myths and confusion that prevails across their customer base. From my perspective when weld equipment and consumable supplies support BS products, it shows disrespect for their customers.

Guys. Keep welding with my 15 % CO2 mix which you can use for all your MIG and your E71T-1 flux cored welds. The 15% CO2 MIG gas mix will meet any weld code, weld quality and weld productivity requirements. And next time you see a salesman who tells you his three part argon Helium C02 mix is the best choice for your steel applicationS, show him this photo on the right and ask him, how can you get better than this?






DOWN GOES THE BERLIN WALL, OUT COMES THE GAS:

Thanks to the fall of the Berlin wall, an ironic weld situation developed. Europeans and Americans gained access to a low cost source of helium.

After decades of not needing helium gas mixes for steels and stainless MIG applications. The European gas manufacturing companies got on the gravy train, copying their American gas cousins and recommending the higher profit Helium tri-mixes for both stainless and carbon steel MIG weld applications.

ONCE YOU ATTAIN MIG PROCESS CONTROL EXPERTISE YOU WILL LEARN AS POINTED OUT IN GAS SECTION ONE, THAT THERE IS NO STAINLESS, ALLOY STEEL OR CARBON STEEL MIG APPLICATION THAT REQUIRES A GAS MIX THAT CONTAINS HELIUM.

E-mail from India.
05/11/03

Dear Mr. Craig,

We had a chance to visit your website recently. We appreciate and respect your experience in MIG/CO2 Welding process. We would like to introduce ourselves as one of the leading manufacturer of MIG/CO2 Welding wire in India.In India almost (99%) of our weld consumers use only CO2 Gas for Welding. Some of our customers report spatter occurs during welding of our wire. We normally advise them to check their MIG Welding equipment like Nozzles, Guns etc.

Now, we would like to know other than end user side and their equipment what are the causes for spatter concerning to consumable CO2 Welding.. In what way we can correct in our CO2 wire manufacturing process to avoid spatter at end user's side. Please advise.


K. BALASUNDARAM
BRIGHT WELDING PRODUCTS
INDIA

Ed's Reply.
When using the common 0.035 , 1 mm wire you cannot avoid weld spatter with CO2 gas once the short circuit weld current is above >150 amps. Once above 150 amps the weld mode goes to an erratic globular transfer. The higher the weld current the greater the weld droplet size, the greater the spatter. The only way to reduce spatter with CO2 is to use a Japanese electronic power source that is deigned for use with straight CO2. Even with this costly equipment weld spatter is only partially reduced when the weld current is >150 amps. This is one reason why Japan a country that also uses mostly CO2, uses a great deal of CO2 flux cored wires on parts > 3 mm.

CO2 WELDS. HIGH WELD SPATTER,
TYPICALLY LOW WELD DEPOSITION RATES

With straight CO2 the weld gas is highly reactive, one of the reasons you require the higher silicon (high deoxidizer) wires like E70S-6. With amps > 150, the CO2 gas plasma (ionized gas) that forms is smaller than an argon plasma and the plasma does not envelop the end of the wire as shown in the following slow motion shot of an argon 10% CO2 mix. Rather the CO2 plasma remains in the arc zone "under the weld drop". While the CO2 plasma is under the drop it helps to support the weld drop as it forms. The C02 weld drop on the wire tip will increase in size and and whirls around. Eventually the weld drop succumbs to gravity and falls to the weld where it explodes on impact scattering weld spatter across the work.



In contrast with argon mixes containing less than 20% CO2, the weld transfer can go from short circuit into an open arc stable spray transfer mode. With spray the plasma surrounds the wire tip and the weld droplet formation. The higher spray current causes the magnetic field that surrounds the wire tip to pinch the end of the wire tip to a point. The higher the current the thinner the wire tip point. The spray stream of weld metal and micro droplets is detached and transfers the molten metal directly to the weld, without spatter. This occurs as long as the correct current and voltage is utilized.



The bottom line on most applications under 2 mm, when using CO2 gas an 0.035 wire and "short circuit" weld current <150 amps with 16 to 23 volts, the small weld drop will transfer between the wire tip and weld metal due to the wire contact and capillary action between the droplet and work. In this parameter range you can produce minimum weld spatter with CO2 and the short circuit mode. By the way this weld parameter range is suited to steel applications <2.2 mm. When you need to weld thicker parts you need more weld current (more wire feed) and the CO2 will then only provide erratic open arc globular transfer. The greater the wire feed (current) used the more spatter you can expect. Most welders using CO2 will use low wire feed rates (lower weld deposition rates) than when the welds are made with argon mixes. The use of straight CO2 this has a negative impact in productivity, quality and weld costs. My MIG and flux cored books would be good reading.

Regards Ed Craig.

 

Gas Fact: "Weld fluidity", Terminology and Marketing Bull.

How many times have you seen a gas brochure state this three component gas mix adds to the weld fluidity.

If the people who write the common MIG gas marketing dribble, had ever welded a 5/16 (8 mm) fillet with the spray transfer mode, they would know that with any traditional argon gas mix that a prime problem with the spray weld will be that the welds are typically too fluid.

Yes adding oxygen to an argon CO2 mix increase the weld surface fluidity when you wont need that fluidity, the oxygen will also add something else you don't need, decreased weld fusion potential.

Reducing the wire silicon content by changing from an E70S-6 to an E70S-3 wire and "reducing the CO2 content" in the gas mix will provide a reduction in the spray weld fluidity, improving the weld puddle control and decreasing undercut potential.

Over the last three decades Ed has written hundreds of pages on the influence of gases on MIG welds, check his welding books in "EDUCATIONAL RESOURCES"


In 2006. From a question on the web, I pulled the following weld gas advice from Dave Comer an Air Liquide employee. Dave was giving advice on how weld gases can reduce weld undercut. As with most of the weld advice provided by the major gas companies, this advice was better suited to children in kindergarten than it was for employees in a weld shop.

One of the primary problems we have in the welding industry today is too many under qualified people are prepared to provide technical weld advice to customers who will not spend five minutes reading about the subject that makes profits for their companies and pays their pay checks.

2006. Justification for the more costly three part gas mix.
From Dave Comer, Air Liquide.

Argon-CO2 mixtures are used for welding carbon steel or horizontal welds on steel or stainless steel, the quick-freeze characteristics of an argon shielded weld do not permit the molten metal to wet-out to the toes of the weld, causing undercutting at the edges of the weld bead. To minimize the tendency to undercut ferrous metal welds, an addition of 1 - 5% oxygen to argon is recommended. The oxygen superheats the weld metal transferring across the welding arc column. It increases the metal wettability and minimizes the possibility of undercut. Oxygen action also controls the weld bead profile by flattening the weld. To choose the best mixture, keep in mind that the reason for using oxygen additions is to superheat the molten metal. Thus a higher concentration of oxygen must be used when there is a larger volume of molten metal to be superheated.

Reply from Ed: Dave as you know the purpose of this web site is "weld reality" and hopefully to cut the BS out of a so called technical industry that at this time is one step away from becoming as reputable as a bunch of Washington politicians: You represent an industrial gas company where BS has been a a way of life for decades, so I can forgive you for your MIG weld process misinformation. When MIG welding carbon and stainless steels, a reactive gas such as oxygen or CO2 must be added to argon to stabilize electron flow and provided more plasma and weld energy. Oxygen when added to argon as you mentioned heats the weld surface, adding to "surface weld wettability". Dave even a novice weld person would see the relationship of increased weld surface wet ability and the formation of undercut. As for wetting out at the toes, if the correct wire size, weld mode and parameters are selected, their will always be good toe weld fusion with all argon reactive gas mixes.



The problem with any argon oxy mix and MIG spray transfer is the low voltage requirement and low ionization that results from oxygen, provides a narrow, low density arc plasma that can end up producing "finger type" weld penetration profiles.

The argon / oxy, narrow weld penetration will fast freeze and with the higher oxidation potential you can anticipate trapped porosity in the root of the finger profile.

In contrast to the argon oxygen mixes, when using argon CO2 gas mixes and welding steels, these mixes combine provide the unique dissociation properties of CO2 with the weld energy influence of the oxygen molecules in the CO2. This combination enables superior weld energy distribution throughout the weld puddle. Combine good weld fusion profiles with low oxidation of a CO2 mix and that's the simple reason argon CO2 is always superior to argon oxygen on most carbon and steels MIG welds.


By the way anyone who tries to spray weld a fillet weld larger than 6 mm, will know that even when using argon with low C02 content, the welds can become too fluid, highly oxidized and difficult to control. The bottom line, increasing weld fluidity with the addition of oxygen is in my mind more of a detriment than it is a weld benefit.

When weld undercut does occur with any argon mixes, it's likely to be a result of excess weld voltage, poor weld techniques or from using E70S-6 MIG weld wires with excess silicon.

As for needing more oxygen as your weld volume increases, well I don't know where you got that info from, perhaps you have spent too much time with your sales manager or in your companies marketing department. Dave my advice to you, "never give advice unless qualified to do so, not to your customers and never to your wife".

YOU KNOW YOU DON'T HAVE TO SPEND HOURS ON THIS WEB SITE PICK UP MY MANAGEMENT ENGINEERS GUIDE TO MIG BOOK AND THE DATA IS THERE WHEN YOU NEED IT


Robots and Gas Flow Meter Issues.


E Mail Question.

Ed I'm having a hard time keeping flow meters from "blowing their lids" in my plant. We've run both ESAB and Rexarc flow meters and over time they are both failing. At the start of the weld the solenoid opens letting the gas flow into the flowmeter...pegs the BB out on the top of the unit then settles to the set flow rate I have tried snubbers and I have tried having the FM before the solenoid. We have 50 psi, 90%AR 10%CO2 coming down from ceiling to each welder(automation). Then provide a 10-15 ft flex hose to the solenoid, FM is hard plumbed to solenoid, then 4ft flex to 8' Torch bundle.

Do I need to rearrange? Is this common? Surely not! FYI, we have 2000 arc starts/day on these FM's, some last 4 months, others last 4 days! Should I remove the FM altogether and get a set calibrated orifice like at www.okcc.com? I did turn down my pressure leaving my gas mixer to 40psi but all FM's are calibrated at 50psi, so it throws off my readings. Help! :)

Ed's Answer. Most MIG gas flow meters have the pressure regulated at 20 to 30 psi. I would install a pressure gauge at each outlet and lower your gas pressure to the flow meters to 25 psi. Then check the gas flow output delivered from out of each nozzle. Set this flow at 30 - 35 cuft /hr.
ps: Are those products you mentioned manufactured in China?

One MIG gas mix insanity
from the past "Time Gas"

Time Gas, a four component, "born again and again" MIG gas mix. A gas mix promoted to improve weld mechanical properties and increase MIG weld speeds and deposition rates for carbon and low alloy steel welds.


Gas Fact: Four Component "TIME GAS". If you believe that three part gas mixes achieve measurable welding benefits then you will love the four part TIME gas mix from Canada.

The four part gas mix, Helium - Argon- CO2 - Oxy, is gas marketing at its best or worst. This gas mix and maintaining my credibility and integrity is the prime reason I quit working as the gas marketing manager for Liquid Carbonic Canada. Carbonic bought into this snake oil and many of their Canadian and US customers paid the premium price for a gas that delivered nothing. Add helium to argon - CO2 - oxy and you simply increase the voltage required to sustain the arc.

Many American and Canadian Japanese and European companies bought into the TIME gas sales pitch, again this is simply another reflection of the lack of global management and lack weld process expertise that prevails.

2007: More than two decades have passed since the Canadian developed TIME MIG gas mix containing approximately 65% argon - 26.5 %helium - 8% CO2 - 0.5% oxygen was first introduced.

Some US and Japanese companies and their gullible managers bought into the TIME process myth, however the majority of the TIME gas sales in North America were through a company called Liquid Carbonic Canada. This company employed some very confused, ignorant and greedy industrial gas executives who damaged their companies credibility and created havoc for both their distributors gas customers.

After an extensive MIG gas marketing campaign by Liquid Carbonic which achieved nothing more than angry and confused customers for hundreds of Canadian and many Japanese weld shops, the reality of the costly Time Gas set in.

The disillusioned, Time Gas, Carbonic customers, along with the weld process ignorant, Carbonic, industrial corporate executives faced the simple weld reality. They had bought into a Canadian product which in the old days would have gone under the name of "snake oil".

Of course when you can no longer sell your products in North America there is always an easy mark to be found outside the country. The Liquid Carbonic executives sold the Time Gas distribution selling rights to a gullible company in Japan. The four component Time Gas Mix went to Japan, a country with almost no experience with traditional spray transfer and argon MIG gas mixes.

Reference the Time gas claim of "increasing weld deposition rates".

[a] WIRE STICK OUT: The MIG process is limited in the weld current density that can be applied to a specific electrode diameter. As my process control train books emphasize, wire feed settings (current) have distinct maximum limits. However with any gas mix you can increase the MIG wire stick out which reduces the weld current and increases the weld deposition rate.

[b] WELDER COMFORT: When the use of "high weld current capability" is presented in a so called unique weld process or consumable, remember most manual welders are uncomfortable with weld current >380 amps.

[c] EXCESS HEAT AND GRAIN GROWTH: When high >380 amps MIG weld current is used, the weld heat affected zone is subject to extended grain growth and "hot cracks" can result. When I tested Time Gas, this cracking accord in common carbon steel welds.

[d] DISTORTION: Welded parts subject to high weld heat are prone to distortion and increased stresses.

[e] EQUIPMENT: High weld current > 380 amps even when used with water cooled equipment shortens the life of that equipment.

[f] WELD CONTROL: High weld current > 380 amps adds to the degree of difficulty in controlling "weld current fluidity" and also in an agitated weld puddle that leads to inconsistent weld fusion and large pore weld porosity.

[g] CHEMISTRY: High weld heat results in weld surface oxidation, adding to weld porosity for multi-pass welds.

If you want more info on TIME gas you know where I am. Check out the remarks on Time gas in the Weld QA column of this site.

 

MISON A GAS FROM OUT OF SPACE, OR PERHAPS IT'S FROM SWEDEN. WHAT'S THE DIFFERENCE?

Gas Fact: AGA MISON Gas Mixes.

"MISON" developed by AGA.

AGA had great sales of this gas mix in Scandinavian countries. The reasons for the success had little to do with ozone reduction and a lot to do with the reality that AGA was the dominant seller of MIG gases in these countries. When you own the market, any gas marketed aggressively is likely to sell well. The formation of notable amount of ozone will typically occur in an the aluminum or stainless MIG arc plasma where the oxygen formation is influenced by the highly reflection intensity of the bright surface. Typically high weld current and long arc times are required before the ozone smell is noticeable. The formation of ozone is shown in a TIG arc. The higher TIG weld are plasma temperatures makes this process more prone to notable ozone formation than in contrast to a much lower temperature MIG arc..

The welding conditions for notable ozone levels are rare. I have not heard or read of one single case in which medical evidence has shown that aluminum or stainless MIG welding causes medical problems with long term affects. With stainless be more concerned with the chrome reactions than the ozone levels

AGA is today promoting it's ozone reducing gas for "carbon steels. I have set up MIG applications in over 1000 companies that weld steels and only noticed the smell of ozone once on a a single application four torch spray application. Is it right for a company like AGA to ADD TO THE INDUSTRIAL GAS CONFUSION and market a product which in reality will have no impact 999 times out of 1000?




[] OZONE FORMS WHERE OXYGEN IS AVAILABLE JUST OUTSIDE THE GAS PLUME.

OZONE OCCURS WHEN THE OXYGEN MOLECULES SPLIT.



18 INCHES FROM THE ARC OZONE THE OZONE CONTENT IS 1/10



OZONE CAN ALSO OCCUR WITH STEEL MIG WELDS HOWEVER THE ARC
ENERGY AND ARC ON TIME HAS TO BE SUBSTANTIAL. OZONE SMELLS
LIKE BLEACH. THE CEILING VALUE FOR OZONE IS 0.3 ppm

 

AGA "Rapid Arc Process". This is a process that anyone with a little expertise can create without picking up a phone and talking to an AGA sales rep. This process fundamental and gas mix combo promises higher MIG weld speeds.

If you want to weld fast with a regular two part gas mix, no big deal". On specific applications such as 1/8 to 1/4, take an argon 10% CO2 mix and extend the MIG electrode wire stick out.

I have written extensively on the subject of high speed MIG welding. I have patented ceramic / copper contact tips which enable controlled longer MIG wire extension. All the data necessary for high speed welds is found in my "Management and Engineers Guide to MIG" book. Note, the only thing rapid in your weld shop should be the AGA salesman making a rapid retreat.



New Aluminum Mix from Messer, Germany. Monomix and Monomix He.
This company claims the addition of a micro amount of nitrogen to argon or argon helium provides deeper weld penetration and less weld porosity. Its been known for decades that when you add micro amounts of a reactive gas to an inert gas that this stabilizes the arc, increases the electron transfer and increases the stable wire feed speed capability. Less than 1 percent Co2 to argon has the same impact on MIG welding nickel applications.

The real question is do we need this gas mix? Using argon or argon helium for 50 plus years, companies with knowledgeable weld personnel have MIG welded billions of tons of aluminum applications with acceptable weld fusion and porosity. These welds would meet all of today's appropriate weld codes.

If you want more weld energy for additional weld penetration or less porosity on alum welds, as my books indicate there are many ways to attain it,

[a] increase current.
[b] use smaller wires and higher current density,
[c] lower weld voltage to shorten arc length,
[d] shorten wire stick out,
[e] change gun angle,
[f] increase gas flow rates,
[g] slow travel speed.
[h] change pulsed weld parameters.



MIG Gas Question?

Ed we are mixing argon and CO2 on site with a mixer and delivering to our MIG welding robot cells through a common gas manifold piping system. Is there any good way of checking the gas integrity at each weld cell? I am also curious as to what we are actually getting 500 feet from the bulk tanks and mixer? I would like a good way of verifying my actual gas mix at the source. Also will different rubber hose's, piping materials, and possible leaks in the bulk gas piping effect the gas integrity with possible contamination. Can you see the gas effects in the actual weld cycle for trouble shooting?

Answer: There are many portable gas analyzers available that will tell you the amount of the reactive gas delivered to the robot MIG guns. I believe it's a good idea to tell your gas supplier to come to your plant once a year and bring their portable gas analyzer to run a check. If the supplier wants to retain your business they typically will do this for free and this will also meet your ISO requirements. Check the gas composition at the furthest point from the bulk tanks. Certain hoses are poor for gas delivery use hoses that are recommended for argon mixes. Leaks can effect both the gas composition and flow rates, they are easily traced with soap and water. Spray transfer arc inconsistency and weld voltage fluctuations along with weld coloration (oxidation) will provide a clue something is happening with the gas. However, be aware MIG wire chemistry inconsistency and erratic weld transfer from that Panasonic or PowerWave power source are much more likely to cause the erratic arc symptoms. The easy way to check the bulk gas mix is to keep a cylinder of your mix available. When you believe you have a bulk gas issue, switch over to the cylinder and see if the cylinder weld and bulk weld look and sound the same. Gas flow meters should be located as close as possible to the wire feed controls.


09/11/07Question from Terry:

Hi Ed, my QC guy at one of our shops had some 316 flux core to weld. They had not used this before so he had to qualify a procedure and the welders . He did all of this with a helium tri mix. The welds on the header look cold, have leaks and slag inclusions etc. At my shop we use 75/25 Ar/CO2. He told
me that he got info from AWS that tri mix could be used for this. I think he's made a mistake. I have never heard or seen where the tri mix can be used for FCAW. Do you know if the welds can pass mechanical test requirements with tri mix. 90He/7.5/Ar/2.5CO2

Ed's Answer: Its hard to believe 30 years after the introduction of steel and stainless flux cored wires, products by the way that have only ever used two gases, argon CO2 and CO2, that somone in a position of responsibility in a North Ameicane weldshop would try to qualify stainless flux cored welds with the helium tri mix. With this highly inert gas, you will have extensive lack of weld fusion, porosity and slag entrapment, you will also have welds that have exceeded their maximum strength and lost ductility. Tell the inspector that if he wants to stay in welding , that weld process expertise is a part of his job requirement. If he had invested $80 in one of my books he would not have caused weld issues that will cost thousands to repair.

E Mail Question to Ed.

We are a tier one supplier and weld automotive coupling parts and exhaust components. The metals are 1.8 to 2.5 mm thick. We manually and robot MIG weld austenitic 300 series stainless to itself and to carbon steels. We also weld 400 series stainless and carbon steels. At this time we use a gas mix with argon and eight percent CO2 Is their a problem with this mix? and is there a single gas mix we can use for these steels weld joints?

Answer: When welding stainless to stainless , the eight percent CO2 will add minute levels of carbon to the austenitic steels which could provide a corrosion issue. As you weld both steel and stainless thin parts parts that can be welded with low spray parameters, or pulsed transfer, you could use a low energy low reactive mix like argon - 2% CO2.

 

WE NEVER DID NEED SIXTY GLOBAL GAS MIXES FOR THOSE MIG WELD APPLICATIONS:

A welder going to the cylinder rack for a MIG gas mix to use for their carbon steel welds, may have many cylinders sitting in the rack to select from. The MIG gas cylinders rarely will haved data or information that could assist the welder in the selection of the correct cylinder for his or her application. What seemed to be more important to the gas company was to provide a unique brand name for their gas mix. The gas companies marketing strategy was often self centered or based on there own process ignorance. The bottom line, for decades the global the MIG gas product presentation has simply resulted in extensive gas myths and weld customer confusion.

The following is an example of the way gas mixes are identified for the welding customers. This is just a few of the sixty plus available global MIG gas mixes in North America. Keep in mind, the MIG welding world can produce optimum weld results on all the ferrous and none ferrous applications with 6 honest MIG gas mixes. I cannot guarantee the following mixes are correct and this list is certainly not up to date and will be far from complete.

Air Products
COUGAR 95
COUGAR-295
COUGAR-2003
COUGAR-4
COUGAR-25
COUGAR 100 HIFLEX
COUGAR 200
COUGER 250 H
COUGER 295 PLUS
COUGER 400
COUGER 500 SG


COUGER 600
COUGER 700 HI DEP
COUGER 800
COUGER 825
COUGER 900
COUGER CUSTOM
COUGAR SG PULSAR
MEGA 3
MEGA 3
MEGA 2
HYTEC-2
HYTEC-5
HYTEC- 35
MITEC 2

ED'S SIX GAS MIXES FOR ALL MIG WELDS. HOW SIMPLE LIFE COULD BE.

These gas recommendations discussed in these two sections, are directed at getting the weld confusion out of global MIG gas selection. I know the gas mixes I developed or recommend are honest, cost effective and will provide you with real world weld / metallurgical benefits. If your gas supplier states he cannot provide one of these honest mixes, then you may want to consider changing your gas supplier.

Now if gas manufacturers would provide the same logic to gas simplification, the gas companies would get better utilization of their cylinders and their customers would get the best possible gas mixes. Let's not forget those confused weld decision makers. When the welder needs to weld that steel, stainless or aluminum, he no longer has to ask the supervisor what the name or the number on the MIG cylinder means.

 

A message to industrial gas manufacturers & weld distributors.

2002: When MIG welding steels, the welding industry does not need more of your MIG gas confusion. They don't need your your argon oxygen mixes, that useless argon 25% CO2 mix, or your useless 3 and 4 part mixes with additions of helium or nitrogen. You know as well as I do that you show your customers disrespect when you offer them snake oil instead of providing real world solutions to their daily welding problems. Accept the fact that what you sell is a simple commodity, and the best gas service you can provide your customers is honest answers, the correct gas mix, cylinders which are easy to identify and correctly mixes gases.

INDUSTRIAL GAS DATA "ARGON"

AWS SG-A

ARGON NORTH AMERICA CYL VALVE CGA 580

ARGON MANUFACTURED FROM AIR DISTILLATION

ARGON CONTENT IN AIR 0.93% BY VOLUME

Ar BOILING POINT AT 1 atm 101.3kPa 302.53oF -187.87oC

Ar CRITICAL DENSITY 33.44 lb/CF 535.6 kg/cum

Ar CRITICAL PRESSURE 707.2 psi 4874 kPa

Ar CRITICAL TEMPERATURE -188.33oF -122.43oC

Ar DENSITY 32oF 0oC 1 atm 101.3 kPa = 0.111 lb/CF 1.784 kg/cum

ARGON HEAVIER THAN AIR AIR=1 ARGON = 1.38

ARGON FREEZE POINT AT 1 atm -308.66oF -189.28oC

ARGON NON TOXIC WILL CAUSE ASPHYXIATION AT 50% AIR VOLUME

ARGON LIQUID CAUSES FREEZE BURNS

ARGON GAS INSTALLATION USE MOST COMMON METALS

ARGON LIQUID INSTALLATION USE AUSTENITIC NON FERROUS METALS

ARGON CONVERSION DATA

1-lb = 0.4536kg
1-lb = 9.671 CF 0.2543 cu m

1-lb = 0.86 LIQ GAL 0.3255 L
1kg = 2.205-lb

1-kg = 21.32 CF 0.5605 cu m
1-kg = 0.1896 LIQ GAL 0.7176 L

1cu m = 3.933 lb 1.7840 kg
1cu m = 38.04 CF

1cu m = 0.3382 LIQ GAL 1.2802 L
1 LIQ GAL = 112.5 CF 2.957 cu m

1 LIQ GAL = 3.785 LIQ liter
1 liter LIQ = 3.072 lb 1.394 kg

1 liter LIQ = 0.2642 LIQ GAL
1 liter = 29.71 CF 0.7812 cu m

1 CF GAS = 0.02628 cu m
1 CF GAS = 0.1034 lb 0.0469 kg

1 CF GAS = 0.008893 LIQ GAL
1 CF GAS = 0.03366 LIQ liter

INDUSTRIAL GASES
"CARBON DIOXIDE"
AWS SG-C

 

CO2 PROPERTIES AND CONVERSIONS

CO2 NORTH AMERICA CYL VALVE 320

CARBON DIOXIDE CO2 DATA MANUFACTURED FROM WASTE PRODUCTS

CO2 FROM COMBUSTION OF CARBON COMPOUND - OXY eg ETHYLENE IN O2

CO2 CRITICAL DENSITY 29.2 lb/CF 468 kg/cum

CO2 CRITICAL PRESSURE 1070.8 psi 7380 kPa

CO2 CRITICAL TEMPERATURE 87.8oF 31oC

CO2 DENSITY 32oF 0oC 1 atm 101.3 kPa = 0.1234 lb/CF 1.977 kg/cum

CO2 TRIPLE POINT 60 psi 416 kPa -69.9oF -56.6oC

CO2 HEAVIER THAN AIR. AIR = 1 CO2 = 1.5291

CO2 CAN BE ABSORBED BY THE BLOOD FROM LUNGS AND SKIN

CO2 STIMULATES RESPIRATORY RATE 3% CAN INCREASE BREATHING RATE

CO2 TO 5% IN AIR CAUSES HEADACHE TO 10% INCREASES BLOOD PRESSURE

CO2 TO 20% IN AIR CAUSES CRAMPS UNCONSCIOUSNESS STROKE

AT ANY SIGN OF AFFECT MOVE TO VENTILATED AREA

LIQUID CO2 FREE STATE PRODUCES DRY ICE -108oF -78oC FREEZE BURNS

PROVIDE VENTILATED AREA WITH CO2 KEEP CYLINDER UP RIGHT

CO2 HEAVIER THAN AIR - IF LEAKS OCCUR BEWARE GAS AT GROUND LEVEL

DRY CO2 NON CORROSIVE GAS USE WITH MOST METALS

AT HI TEMP ABOVE 1292oF 700oC, CO2 OXIDIZING EFFECT SOME METAL

MOIST CO2 USE ACID RESISTANT STEEL ALLOYS WITH HIGH COPPER

MOIST CO2 USE COPPER BRASS BRONZE - AVOID AIR WITH CO2 MIX

AVOID AMMONIA TRYMETHYAMINE ETHYLAMINE METHYLAMINE WITH CO2

AVOID DIMETHYLAMINE CO2 MAY CAUSE VIOLENT ACTION

CO2 CONVERSION DATA

1-lb = 0.0005 TONS 0.4536kg
1-lb = 8.741 CF 0.2294 cu m

1-lb = 0.118 LIQ GAL 0.4469 L
1kg = .0011 TONS 2.205-lb

1kg = 19.253 CF 0.5058 cu m
1kg = 0.2603 LIQ GAL 0.986 L

1 CF GAS = 0.1144 lb 0.05189 kg
1 CF GAS = 0.02628 cum 0.05113 L

1 CF GAS = 0.0135 GAL
1cu m GAS = 4.36 lb 0.00218 TONS

1cu m GAS = 0.5146 GAL 1.948 L
1cu m GAS = 1.977 kg 38.04 CF

1 LIQ GAL = 8.47 lb 0.00424 TONS
1 LIQ GAL = 3.842 kg 74.04 CF

1 LIQ GAL = 1.9431 cu m 3.785 L
1 LIQ L = 2.238 lb 0.001119 TONS

1 LIQ L = 1.0151 kg 19.562 CF
1 LIQ L = 0.5134 cu m 0.2642 GAL

 

INDUSTRIAL GASES NITROGEN

AWS SG-N

 

 

NORTH AMERICA N2 CYL VALVE CGA 580

N2 MANUFACTURED SAME AS OXYGEN DISTILLATION OF AIR

N2 COLORLESS TASTELESS NONFLAMMABLE

N2 CANNOT SUPPORT COMBUSTION INERT EXCEPT AT HI TEMP

N2 BOILING POINT AT 1 atm 101.3 kPa -320oF -195.8oC

N2 IONIZATION ENERGY 14.5 VOLTS

N2 CRITICAL LIMITS DENSITY 19.6 lb/CF 314 kg/cum

N2 CRITICAL LIMITS PRESSURE 493 psia 3400 kPa

N2 CRITICAL LIMITS TEMPERATURE -232.29oF -146.85oC

N2 DENSITY AT 70oF 1atm 101.3kPa 0.0724 lb/CF

N2 DENSITY 21.1oC 101.3kPa 1atm 1.1605 kg/cum

N2 MELTING POINT 1atm 101.3kPa -345.7oF -209.8oC

N2 RELATIVE DENSITY AT 68oF 20oC 1atm = 0.967 AIR=1

N2 CAN CAUSE ASPHYXIATION 50% IN AIR CAUSES SUFFOCATION

N2 LIQUID CAUSES FREEZE BURNS

GASEOUS N2 INSTALLATION COMMON METALS MAY BE USED

USE AUSTENITIC METALS FOR LIQUID NITROGEN

N2 CONVERSION DATA
1-lb = 13.803 CF 0.3627 cum

1-lb = 0.1481 LIQ GAL 0.5606 L
1-lb = 0.4536kg

1kg = 2.205-lbs
1kg = 30.42 cf 0.7996 cum

1kg = 0.3262 LIQ GAL
1kg = 1.2349 liter

1 cum = 2.757 lb 1.2506 kg
1 cum = 0.408 LIQ GAL 1.544 L

1 LIQ GAL = 6.745 lb 3.06 kg
1 LIQ GAL = 93.11 cf

1 LIQ GAL = 2.447 cum 3.785 L
1 Liter = 1.782 lb LIQUID

1 liter = 0.8083 kg 0.2642 GAL
1 liter = 24.6 cf 0.6464 cum

N2 GAS 1 cf = 0.02628 cum
1 cf = 0.0724 lb 0.0329 kg

N2 GAS 1 cf = 0.01074 LIQ GAL
1 cf = 0.04065 liter

 

INDUSTRIAL GAS DATA
HELIUM
AWS SG-He

HELIUM NORTH AMERICA CYL VALVE CGA 580

HELIUM DATA - AN INERT GAS He MOLECULAR WEIGHT 4.003

HELIUM EXTRACTED FROM HELIUM BEARING NATURAL GAS

HELIUM BOILING POINT 1 atm 101.3kPa = -452oF -268.9oC

HELIUM DENSITY AT 32oF OoC 1 atm 0.0111 lb/cf 0.1785 kg/cum

He RELATIVE DENSITY 32oF 0oC 1 atm 101.3kPa = 0.138 AIR=1

HELIUM IONIZATION ENERGY 24.6 VOLTS

HELIUM CRITICAL DENSITY 4.347 lb/cf 69.64 kg/cum

HELIUM CRITICAL PRESSURE 33.82 psi 233.1 kPa

He CRITICAL TEMPERATURE -450.27oF -267.95oC

He MELTING POINT AT 0.037 atm 3.757 kPa = -456.03oF -271.15oC

He CAN CAUSE ASPHYXIATION 50% IN AIR CAUSES SUFFOCATION

He LIQUID CAN CAUSE SERIOUS FREEZE BURNS

AUSTENETIC GRADES MAXIMUM 0.08% CARBON MAGNESIUM

AUSTENETIC GRADES 0.5-6% MAGNESIUM FOR LIQUID He

He GOOD DIFFUSION CAPABILITY SEALS GASKETS MADE FROM TEFLON

HELIUM CONVERSION DATA
1-lb = 96.71 cf 2.542 cu m

1-lb = 0.9593 LIQ GAL 3.631 L
1-lb = 0.4536kg

1kg = 2.205-lb 213.2 cf
1kg = 2.115 GAL 8.006 L

1 cf GAS = 0.01034 lb 0.0047 kg
1 cf GAS = 0.02628 cu m

1 cf GAS = 0.00992 GAL 0.0375 L
1cu m GAS = 0.3935 lb 0.1785 kg

1cu m GAS = 38.04 cf
1cu m GAS = 0.3775 GAL 1.429 L

1 LIQ GAL = 1.0423 lb 0.4728 kg
1 LIQ GAL = 100.80 cf 2.649 cu m

1 LIQ GAL = 3.785 liter
HELIUM

 

INDUSTRIAL GAS DATA
HYDROGEN
SG-H

 

 

HYDROGEN NORTH AMERICA CYL VALVE CGA 350

HYDROGEN DATA MANUFACTURED BY ELECTROLYSIS

HYDROGEN ALSO MANUFACTURED BY OXIDIZING COAL OR HYDROCARBONS

HYDROGEN COMBUSTION TEMP IN AIR 3713oF 2045oC OXY 4820oF 2660oC

H2 AUTO IGNITION TEMP AT 1 atm 101.3kPa IN AIR 1060oF 572oC

H2 AUTO IGNITION TEMP AT 1 atm 101.3kPa IN OXY 1040oF 560oC

H2 BOILING POINT AT 1 atm -422.96oF -252.76oC

H2 EXPLOSIVE LIMIT IN AIR 4.1-74.2% IN OXY 4.7-93.9%

H2 CRITICAL DENSITY 1.94 lb/cf 31 kg/cum

H2 CRITICAL PRESSURE 188.2 psi 1297 kPa

H2 CRITICAL TEMPERATURE -399.80oF -239.91oC

H2 DENSITY AT 70oF 21oC 1 atm 101.3kPa 0.0052 lb/cf 0.0834 kg/cum

H2 IONIZATION POTENTIAL 13.5V H2 IS COLORLESS AND FLAMMABLE

H2 IS LIGHTER THAN AIR AIR=1 H2 = 0.069

H2 BURNS IN AIR IN AN ALMOST INVISIBLE FLAME

H2 IGNITES EASY H2 + OXY OR AIR FORM AN EXPLOSIVE GAS

H2 COOLED TO ITS BOILING POINT
IS TRANSPARENT ODORLESS LIQUID

AS LIQUID H2 IS ABOUT 25% AS HEAVY AS WATER

H2 LIQUID TO GAS EXPANDS APPROXIMATELY 850 TIMES

H2 CAUSES ASPHYXIATION AT 50% VOLUME IN AIR

H2 AS LIQUID CAN CAUSE SERIOUS FREEZE BURNS

AVOID CHLORINE FLUORINE BROMINE WITH H2 - EXPLOSIVE RESULTS

H2 IGNITES ON CONTACT WITH PLATINUM - Cu OXIDE N2 OXIDES

H2 WILL REACT VIOLENTLY WITH PULVERIZED NICKEL - MAGNESIUM

H2 WILL REACT VIOLENTLY WITH ISOPROPYL ALCOHOL Ca CARBONATE

H2 ESCAPING GAS IGNITES SPONTANEOUSLY

BEFORE OPENING CYLINDER VALVE VERIFY REGULATOR CONNECTION

STORE H2 IN A NO FLAME AREA WITHOUT OXIDIZING GASES

H2 MOST METALS THAT SUPPORT OPERATING PRESSURE MAY BE USED

H2 DON'T USE POROUS METALS DIFFUSION THROUGH POROUS METALS

H2 LEAKS OCCUR EASY THROUGH REGULAR GAS JOINTS

USE FLASHBACK PREVENTION DEVICES WITH H2

H2 CONVERSION DATA
1-lb = 192 cf 5.047 cu m

1-lb = 1.6928 LIQ GAL 6.408 L
1-lb = 0.4536kg

1kg = 423.3 cf 11.126 cu m
1kg = 3.733 GAL 14.128 liter

1kg = 2.205-lb
1 GAL = 0.5906 lb 0.2679 kg

1 GAL = 113.41 cf
1 GAL = 2.981 cu m 3.785 liter

1cu m = 0.1982 lb 0.0899 kg
1cu m = 0.336 LIQ GAL 1.27 L

1cu m = 38.04 cf
1 liter = 30 cf 0.788 cu m

1 liter = 0.2642 GAL
1 cf GAS H2 = 0.0052 lb

1 cf GAS H2 = 0.00236 kg
1 cf GAS = 0.02628 cu m

1 cf GAS = 0.0088 LIQ GAL
1 cf GAS = 0.0334 liter LIQ

 

FOR FUEL GAS DATA CLICK HERE:

The MIG Weld Gas Test:

 

Click here for MIG Gas and "Fuel Gas",
Physics, Data and Gas Conversions

 

 

Looking for European MIG Gas Standard Data
visit http://www.key-to-steel.com/GuidedTour.asp.
Looking for European Electrode Standards. Visit here

 

To attain more MIG gas information take a read of my
MIG Management Engineers book
which covers this subject in all its sales induced glory.