MIG Gas Tips and Facts. Part 2.
ED provide six optimum low cost MIG mixes for
all global MIG welds. More info in Section 1.
AWS A5.52 is the USA Specification for MIG - TIG shielding gas mixes. I was on the AWS committee that wrote this gas spec. While attending the AWS gas comittee meetings, I would have to waste much of the meeting time convincing some of the other members to keep their sales bias and marketing hype out of this important weld spec.
In my weld product management - development roles with both AGA and Airgas, I developed and introduced, four of the most popular MIG gas mixes used today in North America. I have included extensive MIG gas selection information in part one . These two gas sections are intended to take the sales influence, the mystery and the bovine fecal matter that surrounds the 40 plus available MIG gas mixes sold in North America.
With MIG weld gas selection, we often get
too much flatulence with too few weld facts.
E Mail Question to Ed.
Kevin M Gough
Ed, as you know I ordered your MIG and flux cored book. I love the straight forwardness of the site and your attention to two important details, truth and credibility!.
I have read through most of the posts on your QA 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, the bottom line is they simply can't!
My question is, 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 weld 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.
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 addition of oxygen in any gas mix will influence the weld root fusion profile. Typically a narrow finger penetration profile is produced. This profile is influenced by the oxygen that promotes a lower energy, narrow plasma, and lower energy welds.The result is a 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 personnel have in the past frequently tied together a new gas mix and a 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 more importantly they had respect for their welding customers, they would have realized the metal cored wire and argon - oxy gas combo products that they were presenting was unnecessary and likely doing more harm than good for most welds produced on parts > 4 mm.
Weld process concern and CHRYSLER.
E Mail Question.
Ed. We are just starting out on a new Chrysler project welding a galvanealed 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 weld 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 many of the weld decisions that have been made by this Chrysler, corporate weld engineer. From my perspective, this guy has for more than a decade been in the wrong profession. The choice of the 75-25% CO2 gas restricts the use of the world's most commom weld transfer mode, "MIG Spray Transfer" which is a great transfer mode for robot carbon steel welds on parts > 0.075. Remember, in contrast to manual MIG welds, thanks to the faster weld speed capability of a robot, and the typical short weld lengths, robot spray welds can be made on many thin parts. Also the 75-25% CO2 gas is not suited for the pulsed transfer.
As for using those Self Shielded Flux Cored consumables recommended by the same Chrysler corporate weld engineer, the use of these wires (which in reality should be banned in the auto - truck industry or any company that has pride in the welds they produce) have cost Chrysler and it's supplies millions of dollars in lost productivity, weld rejects and weld rework.
When you get those poor, and innapropriate weld decisions from the auto - truck corporation weld specifications, the specs tend to become imbedded in the plants. Lets face it, the weld engineer responsible would not want to change his mind and let his apathetic engineering peers and managers be aware of who was responsible for the bad weld decisions.
As for the double coating, it makes no sense. What does make sense is a practice thats not used in any auto plant. Coat the parts after welding. The reason the MIG welds destroys the coating in the weld HAZ area, these are the locations where the rust usually starts its journey. As I said before, no one should look for weld engineering 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 MANAGEMENT MADNESS
Airgas and Hobart Concerns:
E-mail from Dan. Feb 2007:
Ed I think your web site is fantastic. I ordered your Management book and training programs 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 companies new "Gold MIG" 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 now MIG weld carbon steels with your Ar + 15% CO2 mix , and have great success with it. We have the gas plumbed through our shop. We buy both the argon and CO2 in bulk, and mix our own.
Ed. 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, and lets face it they are a magazine not a weld shop. When you read any weld articles, first take a look at the writer's profession and then look at they work for. The helium content in that tri mix is not relevant and helium is not necessary for your application. Dan, also remember your weld foreman lacks MIG weld process control expertise and is simply looking for a crutch. If the time he spent talking to that salesman was spent at this web site, he would not need to talk to a salesman. And as for that "SteelMix Extra", the only company that will benefit from that mix is Airgas, as they attain extra sales, lock in accounts and earn extra profits.
NOTE: Many years ago, I provided Peter McAusland the president of Airgas with the first honest MIG gas campaign that was ever presented in North America. One of the gas mixes I introduced I named SteelMix, thats the argon 15% CO2 mix. In contrast to Praxair, Air Liquide, BOC and Carbonic, I ensured that Airgas became the first large North American gas company to tell the truth about MIG gas mixes. As a result of the no BS approach, Airgas had the countries most successful and most profitable MIG gas campaigns.
Today years later, you could ask why would Airgas, the largest weld equipment / consumable supplier in North America want to promote a BS, three part gas mix that contains helium, for steel MIG welds that do not require a three part mix and do not require helium? Perhaps it's simply a new marketing gas campaign, perhaps it's simply weld process ignorance of their management, or perhaps Airgas has an abundant supply of helium that they want to get rid of.
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 simply shows the disrespect they have for their customers.
If you weld carbon and low alloy steels, I simply recommend my argon - 15 % CO2 mix. With this mix you can use it for all your short circuit - spray MIG welds and also use it for those all position 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 about his new three part mix, show him this photo on the right and ask him, how can the welds get better than this?
Down goes the BERLIN WALL, out comes the cheap supply of an inert 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 LEARN AS POINTED OUT IN THIS SECTION AND GAS SECTION ONE, THAT THERE IS NO STAINLESS, ALLOY STEEL OR CARBON STEEL MIG APPLICATION THAT REQUIRES A MIG GAS MIX THAT REQUIRES THREE COMPONENTS OR CONTAINS HELIUM OR OXYGEN.
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. We would like to introduce ourselves as one of the leading manufacturer of MIG/CO2 Welding wires 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.
BRIGHT WELDING PRODUCTS
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 with CO2, 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. Strongly recommend my MIG process control program.
CO2 spatter. porosity &
low deposition rates.
With straight CO2, the weld gas is highly reactive, and this is one of the reasons you require the higher silicon (high deoxidizer) wires like E70S-6 with CO2. With weld 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 tip as shown in the following slow motion video shot of an argon 10% CO2 mix. In contrast, 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, there fore the C02 weld drop on the wire tip will increase in size and and will whirl around in the agitated plasma. Eventually that weld drop will succumbs to gravity and fall into 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". Gas Terminology and sales BS.
How many times have you seen a gas brochure that states, "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 1/4 or 5/16 (8 mm), steel fillet weld with the spray mode, they would know that with any traditional argon gas mix that a prime problem with the spray welds is the welds are typically too fluid and that fluidity increases with multi-pass welds.
Yes adding oxygen to an argon CO2 mix increase the weld surface fluidity, the oxygen will also add something else you don't need, it decreases the weld fusion potential and increases the weld porosity potential.
Apart from decreasing parameters, 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 also 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 higher cost, three part gas mix.
From Dave Comer, who works at 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 a major industrial gas company where frankly corporate, Bovine Fecal Matter has been a a way of life for decades, so I can forgive you for your MIG weld process misinformation and process ignorance.
When MIG welding carbon and stainless steels, a reactive gas such as oxygen or CO2 is added to argon to stabilize and imprrove the 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 CO2 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 1/4, >6 mm, or multi-pass MIG welds, will know that even when using argon with low C02 content, the fillet welds can become too fluid, and the high weld heat can lead to highly oxidized and difficult to control welds as seen on the left.
The bottom line, increasing weld fluidity with the addition of oxygen can be 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 wires or other 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 instead of spenfding hours at this web site whhy not pick up one of my books, self teaching or training resources.
Robots and Gas Flow 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 orifices. By the way 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. Also take a look at what you are buying as gas regulation equipment and make sure its not made in China.
Management insanity with a MIG gas mix called "Time Gas"
The Time Gas mIx, is a four component gas mix containing approximately 65% argon - 26.5 %helium - 8% CO2 - 0.5% oxygen. This born again and again gas mix was promoted with extended WSO and high currents. The gas mix weld benefit claims, were improved weld mechanical properties, increased MIG weld speeds and higher than normal MIG deposition rates for carbon and low alloy steel welds.
MIG Gas Mix Reality: If you believe that three part gas mixes achieve measurable welding benefits then you will love the four part TIME gas mix developed in Canada.
The four part Time gas mix has Helium - Argon- CO2 - Oxy. When you add helium to argon - CO2 - oxy and you simply increase the voltage required to sustain the arc. This product was gas marketing BS and lies at their worst. This so called unique MIG gas mix, and maintaining my honesty, credibility and integrity was the prime reason I quit working as the gas marketing manager for Liquid Carbonic in Canada.
After many years of trying to flog a dead horse, the process ignorant, corporate senior management at Carbonic bought into and invested in this snake oil. The result was numerous North American Carbonic customers, paid a premium price for a gas mix that delivered nothing. This gas mix was purchased by many fortune 500 companies which from my perspective was again simply another reflection of the lack of good global weld management.
After an extensive, costly, MIG gas marketing campaign by Liquid Carbonic, this company achieved nothing more than creating angry and confused customers.
The disillusioned, Time Gas, customers, along with the weld process ignorant, Carbonic, industrial corporate executives, finally faced a simple weld reality. They had bought into a product which in the old days would have gone under another name called "snake oil".
Of course as Carbonic had made investments in Time gas they needed to find an easy mark outside Canada that would buy into the snake oil. The Carbonic executives sold the Time Gas distribution selling rights to a very gullible company in Japan. It was ironic that the four component Time Gas Mix went to Japan, a country with almost no experience with traditional spray transfer and two component argon MIG gas mixes.
Reference the Time gas primary claim of "Increasing Weld Deposition Rates".
[a] WIRE STICK OUT:
The traditional 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 dramatically reduces the weld current enabling and increase in 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, the weld decison makers need to be aware that most manual welders are uncomfortable with weld current >380 amps and most leather gloves provide minimal protection at these high currents.
[c] EXCESS HEAT AND GRAIN GROWTH:
When high MIG weld current >380 amps 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 which was really unusual.
Welded parts subject to high weld heat are prone to distortion and increased stresses.
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 an agitated weld puddle may lead to inconsistent weld fusion and large pore weld porosity.
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. also check out the remarks on Time gas in the Weld QA column of this site.
MISON GAS, another MIG mix that had little weld reality.
MISON a MIG gas mix developed by AGA in Sweden. Developed to reduce weld OZONE.
AGA had great sales of this gas mix in the Scandinavian countries. The reasons for the success had little to do with ozone reduction promised but more to do with the reality that AGA was the dominant seller of MIG gases in these countries. When you own the industrial gas market in a specific country, any gas marketed aggressively is likely to sell well.
The formation of ozone typically occurs in an 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 distinct ozone smell is noticeable. The higher TIG arc 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 and the welder would almost have to stick their nose in the arc which is pretty difficult when wearing a mask. Also I have not heard or read of one single case in which medical evidence has been presented on the affects of ozone. Keep in mind also with many weld shops today benefits from improved ventilation and air flow, abd with stainless welds, the welders need to be more concerned with the chrome reactions than the ozone levels
As ridiculous as it sounds, AGA eventully changed its marketing stratedgy from alum and stainless and promoted it's ozone reducing gas forMIG welding "carbon steels" . I have set up steel MIG applications in over 1000 companies in 13 countries, and only once noticed the smell of ozone and that application had four guns welding close together at the same time. It's not normal for the Swedish (very serious) executives to get involved in bovine fecal matter, however AGA management and their customers fell right into the cow pile with this product.
OZONE forms where OXYGEN is available which is
JUST OUTSIDE THE GAS PLUME.
OZONE OCCURS WHEN THE OXYGEN MOLECULES SPLIT.
16 - 18 INCHES FROM THE ARC OZONE, THE OZONE CONTENT IS 1/10.
TO NOTICE THAT OZONE BLEACH SMELL THE ARC ENERGY AND ARC ON TIME HAS
TO BE SUBSTANTIAL. THE CEILING VALUE FOR OZONE IS 0.3 ppm
AGA & A MIG PROCESS CALLED "RAPID ARC".
This is another BS process that anyone with a little process expertise could create without picking up a phone and talking to an AGA sales rep. 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 - 15 % CO2 mix and extend the MIG electrode wire stick out beyond the normal WSO.
I have written extensively on the subject of high speed MIG welding with extended WSO. I have also patented ceramic / copper contact tips which enable controlled longer MIG wire extension. All the data necessary for high speed automated welds is found in my "Management and Engineers Guide to MIG"book. Note, the only thing rapid in most weld shops should be gas salesman making a rapid retreat.
Another gas mix the industry does not need.
The new ALUMINUM Mix from Messer.
Germany. Monomix and Monomix He.
Trying to get on the AGA bandwaggon, this company claims the addition of a micro amount of nitrogen to argon or argon helium provides deeper weld penetration and less weld porosity. It's 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 40 - 60% helium mixes for the last 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.
Again Im'n surprised at the German engineer. as typically they dont get involved with fecal matter,
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?
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
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.
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?
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.
INSTEAD OF THE SIXTY GLOBAL GAS MIXES, WE ONLY NEED SIX FOR ALL MIG WELDS:
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.
At one time, these were some of Air Product MIG mixes,
COUGAR 100 HIFLEX
COUGER 250 H
COUGER 295 PLUS
COUGER 500 SG
COUGER 700 HI DEP
COUGAR SG PULSAR
Examine the typical MIG gas mix lists above and then in this picture, examine the way gas mixes and cylinders should be presented to a weld shop.
Ed's SIX GAS MIXES FOR ALL MIG WELDS.
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 they cannot provide one of these honest mixes, then you may want to consider changing the gas supplier.
Its also a fact that if gas manufacturers would provide the same logic to cylinder gas simplification, the gas suppliers 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 would have 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 BS and confusion. They don't need your your argon - oxygen mixes or the useless argon - 25% CO2 mix. And they certainly dont need your useless 3 and 4 part mixes with additions of helium, oxygen 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. The best gas service you can provide your customers is provide honest answers, the correct gas mix, cylinders which are easy to identify and correctly mixed gases.
Industrial Gas Data:
OXYGEN PROPERTIES / CONVERSIONS
OXYGEN NORTH AMERICA CYL VALVE CGA 540
LIQUID OXYGEN DATA MOLECULAR WEIGHT "32"
LIQ OXY PROPERTIES BOILING POINT -297.29oF -182.96oC
LIQ OXY MELTING POINT -361.53oF -218.65oC
LIQ OXY HEAT OF VAP 1 atm 91.7 Btu/lb 213.3 kJ/kg
LIQ OXY RELATIVE DENSITY 1 atm 59oF 15oC = 1.105 AIR=1
LIQ OXY SPECIFIC HEAT CAPACITY 70oF 21oC 1 atm = 0.219 Btu/lb
LIQ OXY SPECIFIC HEAT CAPACITY 70oF 21oC 1 atm = 0.917 kJ/kg
LIQ OXY CRITICAL TEMP GAS CANNOT LIQUEFY -180.4oF -118oC
LIQ OXY CRITICAL PRESSURE 725psi TO LIQUEFY AT CRITICAL TEMP
HEALTH HAZARDS - OXYGEN IN AIR BELOW 16% = OXYGEN DEFICIENCY
LIQ OXY CAN CAUSE FREEZE BURNS AVOID CONTACT - WARMER OBJECTS
MOST SUBSTANCES MIXED WITH OXY RESULT IN EXPLOSIVE COMBUSTION
INCREASED OXY IN AIR INCREASES COMBUSTION POTENTIAL
SEPARATE OXYGEN FROM FUEL AVOID FLAMES IN STORAGE AREA
ALL CONTACT SURFACES WITH OXYGEN MUST BE CLEAN
OXYGEN CONTAINERS TO BE CLEAN OF ORGANIC RESIDUES / HYDROCARBONS
OXYGEN CONVERSION DATA 1-lb OXYGEN = 0.105 GAL
1-lb OXY = 0.4536 kg 0.3977 L / 1-lb OXY = 12.076 scf 0.3174 cum
1kg OXY = 2.205-lb 0.8767 L / 1kg OXY = 26.62 scf 0.6998 cum
1kg OXY = 0.2316 GAL / 1scf OXY = 0.08281 lb 0.03756 kg
1scf OXY = 0.02628 cum / 1scf = 0.008691 GAL 0.0329 L
1cu m OXY = 3.151 lb 38.04 scf / 1cu m OXY = 1.429 kg
1cu m OXY = 0.3310 GAL / 1cu m OXY = 1.2528 L
1 GAL OXY = 9.527 lb 4.322 kg / 1 GAL OXY = 3.785 L
1 GAL OXY = 115.1 scf 3.025 cum / 1 liter LIQ = 2.517 lb 30.38 scf
1 liter = 1.1417 kg 0.7983 cum / 1 liter OXY = 0.2642 GAL
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
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
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
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
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
Click here for MIG gas section One.