MIG Welding Gases Section 1.
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MIG Gas facts and Weld Gas Tips.
Five decades of influence of
salesmanship with MIG
"On the subject of salesmanship and MIG
gas mix recommendtaions.
Remember a MIG weld lie told
will eventually become the welding
MIG WELDING GAS SELECTION IN MANY GLOBAL FACILITIES, HAS BEEN
BY MARKETING HYPE AND LIES FROM THE MAJOR GAS
COMPANIES AND WELD PROCESS IGNORANCE FROM WELD GAS DISTRIBUTORS
AND THEIR CUSTOMERS.
Ed Craig 1990:
Whenever you see a new "three"
part gas mix for MIG welding carbon and stainless steels, you
know the gas manufacturing marketing boys are doing their
thing with the introduction of another, useless over priced
MIG gas mix.
A MIG Weld Gas Reality: In a thirty minute practical
weld demonstration, I could demonstrate that all the over
priced, global three part gas mixes used for MIG welding
carbon steels and stainless applications, will provide no
practical weld quality, metallurgical or weld production
Please note this is a subject I have extensive expertise with. I was a key committee member that wrote the AWS A5.32 MIG - TIG
Shielding Gas specifications.
As many of the AWS
specification committees are made up of individuals that
influence marketing decisions in their weld equipment /
consumable manufacturing companies, a good portion of my efforts at the AWS
gas spec meetings was trying to minimize the marketing sales hype
that some of the gas committee members wanted to introduce
into the MIG gas specification.
At the AWS gas specification meetings,
exaggerated claims about a specific companies three part wonder gas
would be discussed each time the committee got together.
Three part and even four part MIG gas mix suggestions were in
abundance. I was not completely successful in my quest for a
none product biased AWS MIG gas specification, however over time
I did eliminate an enormous amount of gas flatulence and gas
mix product bias from the AWS MIG gas
In the weld gas business, you are never more than
one arms length away from sales BS.
Ed at a time out after an AWS MIG Gas Specification meeting.
Weld shops take note: From the global, industrial gas
comes the opportunity for increased gas profits.
I should know a little about MIG gas sales bias and
customer product ignorance, I worked in the industrial gas
business as a training or product manager for Praxair
(Linde), Liquid Carbonic, Air Gas, and AGA. Note: Some of
the gas information on this web site is taken from my
MIG Welding and flux cored weld process
control books or CD training resources
dealing with MIG weld
Immerse a low cost commodity like industrial welding gases in
lies, ignorance, sales hype and general weld shop confusion and you will
increase your customer base and attain higher prices.
What do you know about
MIG gas mixes?
Why not try the MIG gas test
The MIG Welding Gas Test:
STAINLESS MIG WELDING. THE HELIUM TRI GAS MIX AND WELD REALITY:
2000: In the last three decades the biggest
selling gas mix in North America for MIG, stainless gage
applications, has been a helium tri mix gas containing
helium - 7.5 argon and 2.5% CO2.
The weld reality was this costly, Helium tri-mix was unnecessary for most thin
gauge applications. With these application, burn through - distortion and oxidation was the three primary weld issues yet the weld gas companies solution was the world's hottest gas mix.
In the 1980s, Ed developed a MIG Gas Solution
and duplex, 98% Ar - 2%
During the nineteen eighties, I carried out
extensive, stainless MIG gas weld research for a company called AGA. When I examined
the common denominators of the weld issues that occurred with
MIG short circuit, on stainless thin gage welds, I found three
primary weld issues that were prominent with the MIG process.
Weld issue 1. "Distortion"
Weld issue 2. "Oxidation"
Weld issue 3. "Burn through"
The common denominator of the three weld issues is "weld
heat" and yet at that time in the late eighties, when welding thin gage stainless, for more
than two decades the North American weld industry had been
using the Helium Tri Mix, the world's hottest gas mix. The tri mix mix
contained 90% He - 7.5% Ar - 2.5% CO2. The
Helium Tri-Mix was developed by Union Carbide. What most people don't realize is that the Union Carbide research people developed this gas mix for short circuit on gage parts > 0.100. In the control of weld heat related issues, it's illogical to
use the world's hottest gas mix.
As with many weld research subjects, all the common weld options were not included
in the research and the Union Carbide helium tri gas research was therefore very incomplete. The gas research that introduced the helium tri
mix for the thicker gage welds, did not include using low end spray transfer on the > 2.5 mm
gage parts which with the higher weld speeds would have been the logical choice. Even in the
nineteen sixties, all the weld personnel had to do when MIG
welding thick gage parts, was simply use a two part argon oxy gas mix and an 0.035 wire, then change the MIG
parameters to low spray transfer settings. Without the use of helium in the gas mix, the spray mode would provide all
the energy required for the >2.5 mm welds.
However In 1968 as in 2010 the majority of weld personnel would not have known
the low spray parameters required for stainless gage welds in
the 2 to 3 mm range.
Back to the 1980s: With a few weeks of weld research at AGA, I eventually found that
the real solution to the heat related weld issues on
thin stainless parts < 2.5 mm. I took all the helium out of
the ridiculous tri-mix leaving me with argon 2.5% CO2. I knew the 0.5% CO2
made no difference to the welds, so I ended up with a mix containing argon -
2% CO2. Keeping the CO2 content under 5%, ensured no carbon
pick up in the stainless welds. I marketed the gas with
different companies using brand names such as StainMix and
Stainless Mix and Stain - Duplex MIX.
The argon - 2% CO2 mix is ideal for all stainless short
circuit welds using 0.035 wires and welding gages <2.5mm.
For welding thicker metals, these welds should be made with
the same gas using pulsed with 0.045 wires, or low spray with
0.035 - 0.045 wires.
I would like to thank you for the excellent information on
your website, I'm a 4th year welding engineering student at
Penn College of Technology. I'm currently knee deep in my
internship. With the help of your information I was able to
convince management to switch from the helium tri-mix to 98-2
argon-CO2 mix for 300 series stainless steel MIG welds, I'm
also currently running tests to demonstrate that running 100%
CO2 is probably not the most economical situation for
structural steel welds (3/16 angle iron). Thank you again for
all the information on your site, I've been introducing
welding process control and theory information to increase
efficiency both in engineering and fabrication. firstname.lastname@example.org
Ed's Mix. 98% Argon - 2% CO2.
Stainless / Duplex
Short Circuit Weld Benefits:
Argon - 2% CO2 benefits on "gage parts": In contrast to the
higher energy and higher voltages required from a 90% helium
7.5%% Ar - 2.5% CO2 tri-mix, the much lower cost and more gas
in the cylinder, argon - 2% CO2 mix, will when short circuit
or pulsed welding thin gage (<2.5 mm) stainless;
[a] reduce weld burn through potential,
[b] reduce weld distortion potential,
[c] reduce weld oxidation potential,
[d] reduce the potential for all forms of weld cracking.
[e] reduce volt requirements more comfortable for the
[f] reduce stainless weld fumes,
NEXT STEP ELIMINATE 98 ARGON 2 OXYGEN FOR SPRAY: After I finished my gas research on stainless gage parts, I
then turned my gas research attention to MIG spray transfer
on thicker stainless applications which for a few decades were typically MIG
welded with the common 98% Ar - 2 - 5 % oxygen mixes. Please remember in the early eighties we did not have pulsed equipment that worked for two days in a row without doing something weird.
SPRAY and PULSED. STAINLESS STEEL / DUPLEX APPLICATIONS:
For more than four decades in North America, argon 2 to 5%
oxygen were the most common MIG gas mixes sold for welding
stainless steel spray applications. For MIG welding stainless
alloys which should be "protected from an oxygen atmosphere",
the argon oxygen mixes were and still are a poor choice.
For MIG welding > 3 mm stainless welds, I examined the
differences between my low oxidizing argon - 2% CO2 mix and
the traditional argon 2 - 5 % oxygen mixes commonly used for spray and
pulsed MIG applications.
( Note: It's important to remember that one percent oxygen is approx.
ten time more oxidizing than one percent CO2.)
Argon - 2% oxygen Spray fillet on 304 Stainless:
Nov 2008: For decades and still today, MIG Gas
manufacturers and distributors recommend
argon - oxy mixes
for stainless spray and pulsed applications. If you want to
part of the real weld world and reduce the oxidation potential and produce cleaner spray and
pulsed MIG stainless welds, try my argon 2% CO2 mix, by the way it's only been
available for twenty years.
ARGON 2% CO2 SPRAY / PULSED BENEFITS: In contrast to the traditional argon -
oxy mixes, an
argon 2 % CO2 mix results in cleaner, (less
oxidized) welds on stainless spray or pulsed spray
applications. The weld oxide reduction from the argon 2 CO2
mix is especially notable when welding parts > 4 mm.
ARGON 2% CO2 SPRAY / PULSED BENEFITS: In contrast to argon - oxy mixes, the
argon 2% CO2 mix is very beneficial on multipass stainless
welds. With multipass welds the build up of oxidation
elements and surface slags can result in excess weld
porosity or unnaceptable inclusions. The argon 2% CO2 mix is a logical choice for MIG short
circuit, pulsed or spray welds on food industry applications
in which the weld surface cleanliness is important.
Note: In contrast to argon oxy mixes, when using an argon -
2% CO2 mix, on spray or pulsed applications, > 4 mm thick,
you can expect cleaner welds, however when welding thinner
gages keep in mind that most of the black or gray weld
surface oxidation is occurring from the reaction of heated
thin parts and the parts reaction with the oxygen in the atmosphere.
2008: It's taken more than 20 years, but today some gas
companies, consumable and weld equipment manufacturers like
Miller are now recommending my argon 2% CO2 mix for stainless
or duplex alloys.
THE CO2 CONTENT INFLUENCE ON CARBON PICKUP
IN LOW CARBON STAINLESS
What's good for the welding goose
should be good for the welding gander. An important weld
issue neglected by the suppliers of electrodes and the person who provide
weld specifications is an issue which should have a great
influence on the so called acceptance level of CO2 in a MIG
gas when used for welding "L" grade stainless.
While engineers worry about the influence of CO2 on the
carbon content of a stainless weld, they allow the stick
process (SMAW), low carbon stainless electrodes to have a
higher level of carbon content than the equivalent MIG
I believe it's difficult for the
manufacturers of low carbon stainless SMAW electrodes to get
the carbon to levels <0.030%, which is the amount
specified for the low carbon stainless MIG wires. However
this electrode chemistry flexibility creates a ridiculous
double standard from stainless weld consumable manufacturers,
and from an engineering perspective its simply unacceptable.
My argon - 2% CO2 mix does not change the carbon content of a
weld made with a low carbon electrode
USA 1990s: Ed developed these three gas mixes which were
for the majority of all steel, stainless and aluminum
Note Ed's simple 1990S gas marketing approach which
indicated to the customers, what the MIG gas cylinders should be used
for, this was a first in the global gas industry and in 2013 its still a rare event.
When that new gas mix is wheeled
into the weld shop, the weld supervisor may pass the buck and
say "let the welders test the mix".
Ask ten welders including the weld supervisor, the weld
parameter difference between an argon 20% CO2 mix and an
argon 2% oxygen mix and you will get a glazed look from 20
eyes and 10 different answers.
Should weld decision makers
understand MIG weld gas mixes. Why not try this MIG Weld Gas
MIG Welding Gas Reality
That new MIG gas mix wheeled into the weld shop every six
months is often viewed as the crutch that will hopefully be
the solution to the many MIG welding issues that daily occur in the
weld shop. With MIG welding, there simply is no reason to try a
new gas once a month or for gas confusion.
You will never need more than a two component argon CO2 gas
mix for all short circuit, spray and pulsed spray
applications on the majority of carbon steels, low alloy
steels, nickel alloys and stainless steels.
A two component, argon CO2 mix, used with the correct MIG
data and consumables, can provide the highest weld
productivity and meet the weld mechanical, property
requirements of the most stringent ASTM / ASME / API weld
Spray transfer occurs on steels and stainless applications
with specific argon mixes and minimum, narrow weld parameter
range. You have achieved spray when weld droplets smaller
than the wire diameter or a weld stream cascades across an
open arc. Depending on the spray transfer weld parameters
used, the weld stream could also be a combination of both
weld drops and stream.
Pulsed Spray transfer occurs on steels and stainless with
straight argon or argon mixes and specific, wide range of
pulsed weld parameters. You have achieved controlled pulsed
when weld droplets smaller than the wire diameter cascade,
uninterrupted (a rareity) across an open arc.
Spray Transfer MIG Gas Myth.
If you had been around weld shops in the 1980s - 1990s perhaps you read an erroneous MIG gas statement
somewhere that states, "you cannot get spray transfer with an
argon - 15 to 25% CO2 gas mix"
1990: Weld Reality Fact. For thirty plus years, Lincoln,
Miller, BOC, Hobart, Liquid Air, Air Products, Liquid Carbonic
and almost everyone else in North America who made MIG
welding equipment, consumables and weld gases, all stated in
either their weld books or promotional MIG literature, "that
you could not get MIG spray transfer on carbon steel welds
with using more than 10 or 15% CO2 with any MIG electrode
The so called welding experts at these large weld equipment
and consumable companies must have never worn a welding
shield when evaluating gas influence on the MIG spray transfer mode. The weld
reality is if you know what you are doing, with "specific wire
diameters", you can get spatter free spray transfer welds with
argon - 25% CO2, however why use this mix when lower CO2
provides superior transfer at more manageable weld
parameters with all wire diameters.
MIG Gas Fact: Any global weld shop that uses the 75 Ar - 25%
a weld shop without weld management.
For those who doubt that with an
argon mix containing 25% CO2, spray transfer is not
attainable why not put on a welding shield, after all seeing
For this MIG gas test, the object is produce a 1/4, 6 mm
fillet weld on >3/8 (>9mm) plate. Using a 350 amp power
source or larger. Set an "0.045 (1.2mm)" MIG wire feed rate
at 450 in./min (11.4m/min), or place your none digital wire
feed control at the 2 o'clock position. Important, to attain
spray transfer with 25% CO2, you will require a higher than
normal spray transfer weld voltage, typically 32 to 36 volts
is required, (make sure the power source has this
capability). The high weld voltages required for the spray
mode with the 25% CO2 will produce spray transfer in which
the weld droplets and stream are smaller than the wire
The prime negative attribute of using argon - 25% CO2, is the
high amount of CO2 provides high energy and requires high
weld voltages. The resulting high arc heat and weld heat can
be uncomfortable for welders. Also with 25% CO2, the high
weld fluidity that results may cause issues such as undercut
or poor weld puddle control on specific welds.
Note: With an 0.035 (1 mm) MIG wire, consistent spray
transfer "is not attainable with argon - 25% CO2". Spray
transfer is however attainable with the 0.035 wire when using
argon mixes with < 20% CO2.
THE BOTTOM LINE IS THERE IS NO NEED FOR ANY WELD SHOP TO USE
THE 75 ARGON - 25% CO2 GAS MIX, AS THIS POPULAR GAS MIX HAS ALWAYS PROVIDED LESS
THAN OPTIMUM WELD RESULTS FOR MOST OF THE COMMON MIG WELD
Reducing the CO2 gas content in an argon mix to a
maximum of 20% for carbon steel welds, brings the transition
current down and also brings the required spray welding
voltages down to comfortable weld levels in which 25 to 32
weld volts for spray transfer with 0.035 - 0.045 (1 - 1.2 mm)
wires is typical.
1988 or 2008. When will the MIG weld industry grow up?
When confusion reigns in a welding shop, everyone typically
looks for a quick solution and in comes that salesman with
their magician's approach to weld problems that would not occur
if the weld shop had management or supervison weld process expertise.
In the last few decades, you did not have to look far to find a gas sales rep,
ready to introduce his companies new 3 part MIG gas
mix and in 2013, what's changed?
The next picture was a gas companies MIG gas advertisement in a welding magazine.
|The gas company
wants to believe that it's "MIG gas mixes are special" and
will provide your
organization with unique weld benefits.
Take that cape off the cylinder, get rid of
the Sales Bovine Fecal Matter
and any MIG gas mix should simply be considered a low cost commodity.
Providing that so called "unique"
three part gas mix for carbon steel and stainless welds
enables the gas manufactures and distributors to dream up glossy
brochures which enable them to attain new MIG gas accounts and generate
higher gas prices and profits on what should be low cost commodity
Build a gas plant and bingo you have access to the world's
greatest free commodity "air" All the argon, oxygen and
nitrogen you will ever need pulled out of the atmosphere at very low costs. All you then need
is a a distribution system, a marketing manager, glossy
brochures full of unfounded or exaggerated weld claims, add a
few salesmen into the pot and then direct them to find thousands of
gullible weld customers who will pay a premium for the three
or four part gas mixes.
Gas company executives love their annual bonuses and share holders
need to see growth, so each year, the pressure is on the gas
marketing guru to invent unique MIG gas feature benefits, or come
up with a new three or four part gas mix to justify the
higher gas prices charged.
THAT NEW GAS MIX
Carbon Steels and MIG Tri-Mix Gas Facts.
GAS SALES HAVE DONE THEIR JOB: For the last two decades, one the most widely marketed gas
mixes promoted in North America for MIG welding carbon
steels, is a tri-mix containing argon - 5 - 10% CO2 and 1-2% O2.
3 Part Gas Mixes for carbon steels and MIG Weld
Up to the end of the nineteen eighties, the industrial gas
marketing and sales focus was placed on converting straight
CO2 users to more cost effective argon mixes. With the
competition for the highly profitable gas business, the two
part mixes quickly turned to three part and four part
Fact: Every three and four part mix ever sold for MIG welding
carbon steels and stainless offers nothing that cannot be
achieved with two part gas mixes and a little MIG weld process control
In contrast to the lower cost, two part argon CO2 mixes, the
three part argon - CO2 - oxy mixes used for carbon steels,
offer "no practical weld benefits that can be measured" in
terms of weld quality, weld metallurgy or weld
Gas Companies had their chance tp Put Up or Shut Up.
I placed this challenge on this web site in 1999.
The challenge was to any gas manufacturing
In contrast to a two part argon CO2 mix, I believe
that no gas company can show real evidence of
practical, measurable, welding quality / productivity
benefits from any three part "argon - CO2 - oxy" gas
mix when used for welding carbon steels. If a gas
company could prove it's point, I will pay $5000 to any
charity of it's choice.
Its 2013 and of course the gas companies have never responded to this
challenge, why show their ignorance and dirty laundry to their
customers. At the end of the day, the North American
weld gas distributor network with it's 5000 plus
salesmen is in a strong position to promote more
profitable, multi-mixes to an industry that simply does
not know better.
Have you noticed since the introduction of three part MIG gas
mixes, the lack of welding articles on this subject. Have you
also noted that when some one does write an article on the cloudy, MIG
weld gas subject, the author typically represent the gas company
that's trying to promote the
three part mystery gas product.
The gas reality of adding Oxygen to Argon CO2. Thanks to
process ignorance in weld shops, gas marketing lies and salesmen that lack weld process expertise,
three part mixes containing argon / CO2 / Oxy are huge
sellers in North America. If you take an argon CO2 mix and
add oxygen to that mix, you simply "increase the weld
oxidation potential" and lower the weld energy
The oxygen addition in the three part
gas mixes will influence the weld root fusion profile.
When you add oxy typically a narrow finger penetration profile is produced,
influenced by the lower energy narrow plasma, and lower weld energy
The narrow finger fusion
weld profile freezes rapidly trapping the oxygen influenced 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.
Apart from the 40 years that I have evaluated MIG gas mixes,
perhaps you would like another point of view. Back in the
nineteen sixties, the British Welding Institute, (at that
time an unbiased research organization), carried out MIG gas
research. The MIG gas research indicated in contrast to argon
mixes with 5 to 20% CO2, three component gas mixes containing
argon - CO2 - oxygen when used for welding carbon steels
"provided no practical weld benefits". The conclusion, when adding oxygen to an
argon CO2 mix simply lowers the weld energy lowering the weld
fusion potential increasing weld porosity potential.
Tri Mix Welding gas cost facts your welding distributor may not tell you:
2008: ONE OF THE BIGGEST SELLING MIG GAS MIXES IN NORTH
AMERICA FOR MIG WELDING CARBON STEELS, IS A THREE PART
MIG GAS MIX CONTAINING ARGON - CO2. 5-10% - OXY. 1-2%.
GAS COSTS: A THREE PART GAS MIX TYPICALLY COSTS 20 TO 50%
MORE THAN A TWO COMPONENT ARGON - CO2 MIX.
LESS GAS: THE THREE PART MIG GAS MIXES WILL HAVE LESS GAS IN THE
CYLINDER THAN A TWO PART ARGON CO2 MIX. IN CONTRAST, THE
CO2 CYLINDER MIX WILL KEEP YOU RUNNING FOR AN ADDITIONAL
ONE HOUR ARC TIME
LESS WELD INTEGRITY: THE THREE PART MIXES ARE MORE OXIDIZING
THAN ARGON CO2 INCREASING POROSITY POTENTIAL, DECREASING
SIDE WALL WELD FUSION AND PROVIDING LOWER IMPACT
PROPERTIES. THE THREE PART GAS MIXES TYPICALLY PRODUCE
INFERIOR WELD FUSION, (FINGER) PENETRATION. FINGER
PENETRATION LEADS TO A NARROW ROOT BAND IN WHICH THE WELD
ROOT FREEZES SO RAPIDLY THAT GAS PORES MAY NOT HAVE TIME
LESS PERFORMANCE: THE THREE PART MIX IS MORE SENSITIVE TO WIRE
STICK OUT CHANGES, MILL SCALE, COATINGS OR SURFACE
CONTAMINATES. AS THE THREE PART MIX WILL TYPICALLY
REQUIRE LOWER VOLTAGE, (THANKS TO THE OXY) THESE MIXES
HAVE LESS ARC STABILITY WITH MANY HIGH DEPOSITION / HIGH
WELD SPEED APPLICATIONS.
If you still believe a 3 part gas mix is necessary for
welding carbon steels give me a call, I am looking for
investors to buy a boat business in the middle of Kansas. If
you need more convincing my 600 page "Management Guide To
MIG" book has more
than 100 pages on MIG Gas Reality for all applications.
If the world's supply of oxygen
was lost to the weld industry tomorrow,
it would have zero impact on MIG welding.
The weld reality. In the MIG
welding industry there has never been a need for MIG gas
mixes that contain oxygen, however their has always been a
great need for industrial gas companies to sell their
abundant supply of oxygen and increase their gas margins through
the sale of three part gas mixes containing oxy. E. Craig 1991.
2007: ED'S MIG GAS
SIX MIXES FOR THE MAJORITY OF MIG APPLICATIONS.
Ed's Mix. 85% Argon - 15% CO2.
Carbon and low alloy steel applications.
Argon - 15% CO2:
A MULTIPURPOSE GAS MIX FOR MIG / FLUX
AND LOW ALLOY STEEL APPLICATIONS:
Applications: Great multipurpose MIG gas mix: Use with
short circuit, spray, pulsed spray modes. Also for "all
position" flux cored welds on carbon steels, low alloy
steels, stainless, Inconel and duplex.
From the nineteen seventies to the early nineteen nineties,
argon CO2 MIG mixes were few. The most popular two mixes were
argon - 8 % CO2 and argon - 25% CO2.
Argon - 20% CO2 was a
common mix sold in Europe before it was introduced by AGA in the US. Today argon 20% CO2 is a common mix, however it's not uncommon with
some distributors to get more of the lower cost CO2 than you
ask for in the cylinder and many of the 20% CO2 mixes end up with
> 25% CO2.
In the early 1980s while with AGA I introduced a logical gas mix Argon - 15% CO2.
This CO2 content allowed for less opportunity for the MIG gas
contents to go over 23% CO2 which affects the formation of
spray transfer with an 0.035 (1mm wire. In contrast to argon
- 20% CO2. This gas mix enables a slightly lower weld voltage
and provides improved weld puddle control with spray
An argon - 15% CO2 mix is without question the best "high
energy, multipurpose gas mix" for most job shops, structural
steel shops, heavy fabrication shops, pressure vessel or any
shops that manual MIG and flux cored weld carbon steel plate
thicker than 1/4 (>6mm).
The argon 15% CO2 mix is superior to argon - 10% CO2 when
spray transfer is used on steels that have mill scale,
primers, surface contaminates and galvanealed, galvanized /
In contrast to argon - 25% CO2 which cannot provide spray
with an 0.035 wire, the argon - 15% CO2 gas mix provides
With short circuit on gage applications < 2 mm, the argon
- 15% CO2 gas mix is superior to argon 25% CO2 as it can
reduce weld burn - through potential.
The argon 15% CO2 gas mix provides optimum weld results when
used with all position welds using gas shielded flux cored
electrodes welding carbon steels, low alloy steels,
stainless, duplex and Inconel.
The argon 15% CO2 mix is also beneficial for robot or
mechanized "high speed" welds on metals
> 4mm. In contrast
to three part mixes containing argon - CO2 - oxygen, argon
oxygen mixes or argon <15% CO2 mixes, the higher voltages
required for this mix and the higher dissociation (HIGH
ENERGY) properties of CO2 assist in stabilizing the arc and
provide superior weld penetration.
Argon 10% CO2.
PULSED MIG STEEL:
Compatible mix range. CO2. 8 - 12%.
Applications: Best low energy MIG gas mix for spray and or
"pulsed" carbon steel and low alloy steels welds on
< 7 mm components. On many robot or manual carbon steel
welded parts, the weld heat from high wire feed spray or
pulsed welds can cause, distortion, weld burn through or
excess weld fluidity causing weld undercut or oxidation. The
fact that this gas provides lower energy than higher CO2
mixes makes it beneficial for these applications.
What is really interesting about this medium energy gas mix
is that its also the best choice for welding thick steels as
long as the mill scale and other surface contaminates
When spray transfer welding horizontal fillets larger than 6
mm, or multi-pass fillet welds in which the weld heat buildup
is notable, the welder is aware of the high weld fluidity.
Weld fluidity increases as the CO2 content of the gas
increases. Argon with 15 or 20% CO2 produces welds with more
fluidity than argon with 10% CO2. So if you want improved
weld control remember this point.
With this same logic, if you are using the 10% CO2 mix with
the pulsed / spray process on steels > 6 mm thick and you
need more weld fusion , change the gas to a higher CO2 mix
such as 15 - 20% CO2 mix.
Ed's Mix. 98% Argon - 2% CO2.
Argon - 2% CO2.
STAINLESS and DUPLEX APPLICATIONS:.
Composition Range. 1.5 - 2.5% CO2.
I developed this unique stainless MIG gas mix while at AGA in the nineteen
eighties. This very low oxidizing mix is suited for all MIG
short circuit, spray and pulsed on all stainless / duplex weld
and clad applications.
I would also recommend this mix for anyone MIG welding very
thin carbon steel and low alloy steels, gauges < 0.040. Do
not use this mix with any flux cored wires or with GTAW
When welding stainless short circuit applications, forget the
common, more costly 90 helium - 7.5 argon - 2.5 CO2 tri mix,
a premium priced gas mix that the major gas suppliers love to
sell, instead use this lower cost, more effective argon 2%
COMPARE WITH HELIUM TRI- MIX? In contrast to the more costly, higher
energy, helium tri-mix, the argon - 2% CO2 mix when used on
thin gage applications can provide;
 less part distortion,
 less weld burn through potential,
 less contact tip issues,
 improved arc stability,
 lower cost gas,
 more gas in the cylinders,
 less opportunity for stress corrosion cracks, hot crack,
and micro cracks.
COMPARE WITH ARGON - OXYGEN MIX? In contrast to the argon oxygen MIG mix
recommended by all the gas companies for stainless spray and
pulsed applications, my argon 2% CO2 mix can result in less
oxidized, cleaner MIG spray or pulsed welds with less weld
Note: When used for "low carbon" stainless applications, the
carbon content in the weld will be acceptable with this low
CO2 gas mix for all short circuit, pulsed and spray stainless
Ed's Mix. 98% Argon - 2% CO2 - 1 % Nitrogen.
Argon - 2% CO2 - 1% Nitrogen.
Mixing range. Nitrogen 0.75 to 1.75%
Suited to MIG Duplex Applications.
Mixing range. CO2 1.5 - 2.5%.
I developed this special MIG mix in the early nineteen
nineties. On many duplex applications, the stainless gas
argon 2% CO2 mix is sufficient. However if you need to
increase your duplex mechanical MIG weld properties you
should try this mix.
In many instances three part mixes are nothing more than a
sales tool, however when MIG welding duplex, a touch of
nitrogen in the MIG mix can be beneficial.
DUPLEX AND CO2 CONTENT: Again note the very low CO2 content,
enough to stabilize without oxidation or carbon pick up
DUPLEX AND NITROGEN CONTENT: When added to a weld, a small
amount of nitrogen can be a potent austenite stabilizer. The
addition of nitrogen to the duplex weld / steel will promote
structural hardening by a solid solution mechanism. The small
nitrogen addition therefore can raise both the yield strength
and ultimate strengths of the duplex without impairing
toughness. The low CO2, combined with the benefits of low
nitrogen content, truly make this gas mix unique.
This mix will also provide stable short circuit, pulsed and
spray transfer. If you are using short circuit, STT or RMD
for pipe roots, first try the stainless duplex gas listed
above, (argon 2 CO2). If the Duplex root or fill pass weld
mechanical properties need to be increased try this gas
If more weld fluidity is need for pulsed MIG or spray
transfer on fillet welds and pipe fill passes on those duplex
applications welds, try the following gas mix recommended for
the MIG Nickel applications
Using the flux cored wires for duplex, use the argon 18 - 25
% CO2 mixes.
It's beneficial with cylinders that contain very small
amounts of a gas, if the cylinders contain dip tubes for
complete gas mixing. I would order this gas mix through a
specially gas supplier and ask for a certificate of
Ed's Mix. 59% Argon - 40% Helium - 1 % CO2. Nickel Applications.
Argon - 40%Helium - 1% CO2:
Mix range. CO2. 0.75 to 1.5%.
Note: The low CO2 content must be carefully mixed and
controlled. Order cylinders with dip tubes. Pay a little more
and order from specially gas facility to ensure the mix is
This is when you can benefit from a tri-mix. I developed this
very unique mix in the nineteen eighties. How many of you
have read in welding literature that when MIG welding nickel
alloys, the gas mix cannot utilize a reactive component like
oxygen or carbon dioxide. For decades this was another
welding myth that had a negative impact on companies that MIG
welded nickel alloy applications.
When using the recommended straight argon for Nickel
applications with MIG spray or pulsed welds, the wire feed
range was restricted, lack of weld fusion was common, and
magnetic disruptions of the arc was a regular occurrence.
Being aware of the oxidation concerns with nickel welds and
the benefits of low oxidizing CO2, I decided to try very
small amounts of CO2 added to argon.The 1% CO2 did not
oxidize the nickel welds and provided substantial weld
benefits for MIG welding nickel alloys.
NICKEL AND CO2 CONTENT: When using straight argon, to
maintain arc stability the wire feed rate was restricted. The
1% CO2 addition allows for increased arc stability through
improved electron transfer without concern for oxidation
contamination of the weld. The 1 % CO2 enabled higher wire
feed rates which provided higher current capability improving
weld fusion. The higher wire feed also allows higher
automated / robot weld speeds and higher weld deposition
rates for the nickel alloy welds. The 1% CO2 content also
dramatically improved the weld fluidity of the sluggish
nickel alloy welds improving the weld fusion potential.
Nickel alloys are sensitive to magnetic fields which disturb
the MIG arc. The 1% CO2 assists in arc / electron
stabilization, reducing the effects of magnetic disturbances
and stabilizing the pulsed or spray weld transfer. After I
stabilized the Nickel welds at higher than normal wire feed
rates, I needed another gas addition to promote more weld
energy for superior side wall fusion. I added helium.
HELIUM CONTENT: Some MIG gas mixes with 10 to 25% helium are
recommended for Nickel alloy welds, however the weld effects
are minimal. If you really want to add energy and fluidity to
that weld, get the helium content up to 40%. Too much helium
can add to the arc instability and also reduces the arc
cleaning potential. As my 40% helium mix contains 1% CO2 you
won't have to worry about the arc stability which is
typically an issue with argon helium mixes.
You will pay more for my mix and possibly have to order it
from a company that provides special gas mixes, however with
the increased wire feed rate potential and superior weld
fusion, you will reduce your weld labor costs by at least 30%
and dramatically reduce the weld rework required on those
costly nickel alloys.
This mix is also recommended for duplex applications in which
additional weld energy is required. More info on this gas mix
and its use for alloy welds is available in my Management
Engineers guide to MIG book.
ALUMINUM MIG > 6 mm.
Argon- 40% Helium.
Typically straight argon works well on many spray and pulsed
aluminum applications. When MIG welding aluminum parts
thicker than 6 mm and improved weld fusion or less weld
porosity is required, the solution is additional weld energy.
The addition of helium provides more weld energy. It's
important not to put to much helium into the mix as you can
reduce the arc stability and the cleaning action. The larger
argon molecules and reverse polarity are responsible for the
aluminum oxide removal, (cleaning action).
TIP TIG WELDS ANY METAL ANY POSITION WITH ONE GAS.
ED OPTIMIZED ROBOT AND MANUAL WELDS FOR HUNDREDS OF COMPANIES.
A FEW OF ED'S PROCESS OPTIMIZATION PROJECTS,
FORD F 150 FRAMES -
VOLVO CABS - CORVETTE FRAMES-
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ED ALSO ESTABLISHED
THE ROBOT WELD FOR THE
WORLD'S LARGEST CATERPILLAR TRUCK.
click here for Ed's best practices
/ process control materials.