MIG welding with Nitrogen?

[Cursitor Doom]

Gentlemen,

I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?

CD

[Peter Hill]

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Nitrogen is used as a blanketing gas on back of stainless steel welds.
This site says it won't work on mild steel.
https://weldingpros.net/types-of-welding-gases/

[Brian Gaff]

Nitrogen, if I remember my science is not inert in the same way as argon.
After all you get nitrides and nitrates and plants also use it, so I guess
something given off by steel might combine with it and screw things up.
Brian
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This newsgroup posting comes to you directly from...
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Blind user, so no pictures please
Note this Signature is meaningless.!

Post by Peter Hill

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Nitrogen is used as a blanketing gas on back of stainless steel welds.
This site says it won't work on mild steel.
https://weldingpros.net/types-of-welding-gases/

[newshound]

Post by Peter Hill

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Nitrogen is used as a blanketing gas on back of stainless steel welds.
This site says it won't work on mild steel.
https://weldingpros.net/types-of-welding-gases/

As Brian implies, nitrides in steels change the mechanical properties.
I'm not surprised that professionals don't recommend it on mild steel,
but surely you have nothing to lose by doing some trials on dummy
specimens. It all depends on how critical your welds are.

[Cursitor Doom]

On Sat, 5 Sep 2020 10:35:17 +0100, newshound

Post by newshound

Post by Peter Hill

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Nitrogen is used as a blanketing gas on back of stainless steel welds.
This site says it won't work on mild steel.
https://weldingpros.net/types-of-welding-gases/

As Brian implies, nitrides in steels change the mechanical properties.
I'm not surprised that professionals don't recommend it on mild steel,
but surely you have nothing to lose by doing some trials on dummy
specimens. It all depends on how critical your welds are.

Problem is, the welds might *look* totally fine but be compromised
strength-wise, as implied by the remarks on the site Peter pointed to.
Since some of the stuff I'm doing is structural, I'm not convinced
it's worth taking any chances with. Be interesting to experiment with,
nevertheless.

[newshound]

Post by Cursitor Doom
On Sat, 5 Sep 2020 10:35:17 +0100, newshound

Post by newshound

Post by Peter Hill

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Nitrogen is used as a blanketing gas on back of stainless steel welds.
This site says it won't work on mild steel.
https://weldingpros.net/types-of-welding-gases/

As Brian implies, nitrides in steels change the mechanical properties.
I'm not surprised that professionals don't recommend it on mild steel,
but surely you have nothing to lose by doing some trials on dummy
specimens. It all depends on how critical your welds are.

Problem is, the welds might *look* totally fine but be compromised
strength-wise, as implied by the remarks on the site Peter pointed to.
Since some of the stuff I'm doing is structural, I'm not convinced
it's worth taking any chances with. Be interesting to experiment with,
nevertheless.

I was quite impressed by that site until I came to this:

"Propylene isn’t actually a pure gas, it’s a blend with Oxygen"

Otherwise a fair point. But remember we usually assume that structures
contain defects. So, where possible go for redundancy, or proof loading.

But yes, it does very much depend on the application. My welding is such
rubbish that I wouldn't do it on anything important. I still remember
Florian Camathias killing himself because of a bad weld (although I
thought it was reported as a braze).

[Peter Hill]

Post by newshound

Post by Cursitor Doom
On Sat, 5 Sep 2020 10:35:17 +0100, newshound

Post by newshound

Post by Peter Hill

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Nitrogen is used as a blanketing gas on back of stainless steel welds.
This site says it won't work on mild steel.
https://weldingpros.net/types-of-welding-gases/

As Brian implies, nitrides in steels change the mechanical properties.
I'm not surprised that professionals don't recommend it on mild steel,
but surely you have nothing to lose by doing some trials on dummy
specimens. It all depends on how critical your welds are.

Problem is, the welds might *look* totally fine but be compromised
strength-wise, as implied by the remarks on the site Peter pointed to.
Since some of the stuff I'm doing is structural, I'm not convinced
it's worth taking any chances with. Be interesting to experiment with,
nevertheless.

"Propylene isn’t actually a pure gas, it’s a blend with Oxygen"
Otherwise a fair point. But remember we usually assume that structures
contain defects. So, where possible go for redundancy, or proof loading.
But yes, it does very much depend on the application. My welding is such
rubbish that I wouldn't do it on anything important. I still remember
Florian Camathias killing himself because of a bad weld (although I
thought it was reported as a braze).

I suspect welding steel with N2 as the shield gas would be like an
uncontrolled plasma nitriding process. The weld could very easily be
more hard and brittle than desired.

EN8 and some cast irons can be plasma nitrided and welding steel is
basically a plasma process to deposit cast steel.
https://www.wallworkht.co.uk/content/plasma_nitride/

[Cursitor Doom]

Post by Peter Hill

Post by Cursitor Doom
On Sat, 5 Sep 2020 10:35:17 +0100, newshound

Post by newshound

Post by Peter Hill

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Nitrogen is used as a blanketing gas on back of stainless steel welds.
This site says it won't work on mild steel.
https://weldingpros.net/types-of-welding-gases/

As Brian implies, nitrides in steels change the mechanical properties.
I'm not surprised that professionals don't recommend it on mild steel,
but surely you have nothing to lose by doing some trials on dummy
specimens. It all depends on how critical your welds are.

Problem is, the welds might *look* totally fine but be compromised
strength-wise, as implied by the remarks on the site Peter pointed to.
Since some of the stuff I'm doing is structural, I'm not convinced
it's worth taking any chances with. Be interesting to experiment with,
nevertheless.

"Propylene isn’t actually a pure gas, it’s a blend with Oxygen"
Otherwise a fair point. But remember we usually assume that structures
contain defects. So, where possible go for redundancy, or proof loading.
But yes, it does very much depend on the application. My welding is such
rubbish that I wouldn't do it on anything important. I still remember
Florian Camathias killing himself because of a bad weld (although I
thought it was reported as a braze).

I suspect welding steel with N2 as the shield gas would be like an
uncontrolled plasma nitriding process.

Sounds pretty cool!

Post by Peter Hill
The weld could very easily be
more hard and brittle than desired.

That was my concern also.

Post by Peter Hill
EN8 and some cast irons can be plasma nitrided and welding steel is
basically a plasma process to deposit cast steel.
https://www.wallworkht.co.uk/content/plasma_nitride/

Anyway, I suspect using N2 as a shield on structural areas of a
vehicle could seriously come back and bite me on the arse, so I'll
hang back until some more argon turns up.

[newshound]

Post by Peter Hill

Post by newshound

Post by Cursitor Doom
On Sat, 5 Sep 2020 10:35:17 +0100, newshound

Post by newshound

Post by Peter Hill

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Nitrogen is used as a blanketing gas on back of stainless steel welds.
This site says it won't work on mild steel.
https://weldingpros.net/types-of-welding-gases/

As Brian implies, nitrides in steels change the mechanical properties.
I'm not surprised that professionals don't recommend it on mild steel,
but surely you have nothing to lose by doing some trials on dummy
specimens. It all depends on how critical your welds are.

Problem is, the welds might *look* totally fine but be compromised
strength-wise, as implied by the remarks on the site Peter pointed to.
Since some of the stuff I'm doing is structural, I'm not convinced
it's worth taking any chances with. Be interesting to experiment with,
nevertheless.

"Propylene isn’t actually a pure gas, it’s a blend with Oxygen"
Otherwise a fair point. But remember we usually assume that structures
contain defects. So, where possible go for redundancy, or proof loading.
But yes, it does very much depend on the application. My welding is
such rubbish that I wouldn't do it on anything important. I still
remember Florian Camathias killing himself because of a bad weld
(although I thought it was reported as a braze).

I suspect welding steel with N2 as the shield gas would be like an
uncontrolled plasma nitriding process. The weld could very easily be
more hard and brittle than desired.
EN8 and some cast irons can be plasma nitrided and welding steel is
basically a plasma process to deposit cast steel.
https://www.wallworkht.co.uk/content/plasma_nitride/

Yes, you would certainly get significant nitride formation. Some
brittleness might be tolerable in a compression structure. But I still
think it would be interesting to try on a test piece, followed by a
standard extreme bend test. I'd have some confidence if it survived that.

[Cursitor Doom]

On Sun, 6 Sep 2020 12:30:50 +0100, newshound

Post by newshound
Yes, you would certainly get significant nitride formation. Some
brittleness might be tolerable in a compression structure. But I still
think it would be interesting to try on a test piece, followed by a
standard extreme bend test. I'd have some confidence if it survived that.

Not me. What if the brittleness only develops over a period of weeks
or months later? This would really need a long-term test under
carefully controlled conditions before we could place any faith in its
application in structural work. And I'm assuming that's already been
done at some time and the results found wanting.

[newshound]

Post by Cursitor Doom
On Sun, 6 Sep 2020 12:30:50 +0100, newshound

Post by newshound
Yes, you would certainly get significant nitride formation. Some
brittleness might be tolerable in a compression structure. But I still
think it would be interesting to try on a test piece, followed by a
standard extreme bend test. I'd have some confidence if it survived that.

Not me. What if the brittleness only develops over a period of weeks
or months later? This would really need a long-term test under
carefully controlled conditions before we could place any faith in its
application in structural work. And I'm assuming that's already been
done at some time and the results found wanting.

Maybe if you kept it at high temperatures, but that's just not the way
nitrogen behaves in steel at ambient temperature.

Case hardening and gas nitriding have been around for a long time.

[F Murtz]

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Just use straight CO2

[Cursitor Doom]

Post by F Murtz

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Just use straight CO2

Ain't got nun. All I have here currently is a full sized cylinder of
UHP Hydrogen and a half-sized N2; both full.

[newshound]

Post by Cursitor Doom

Post by F Murtz

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Just use straight CO2

Ain't got nun. All I have here currently is a full sized cylinder of
UHP Hydrogen and a half-sized N2; both full.

Get a reel of cored wire?

[Cursitor Doom]

On Sun, 6 Sep 2020 12:31:42 +0100, newshound

Post by newshound

Post by Cursitor Doom

Post by F Murtz

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Just use straight CO2

Ain't got nun. All I have here currently is a full sized cylinder of
UHP Hydrogen and a half-sized N2; both full.

Get a reel of cored wire?

Well I was wondering about that stuff, Newsy. I know it creates extra
splatter compared to shielded, but that wouldn't matter in this case.
But isn't it a bit too much like normal arc/stick welding? And if so,
it's going to blow holes in the typically 0.7-0.8mm mild steel used
for car sills and other structural areas like outriggers, surely?

[newshound]

Post by Cursitor Doom
On Sun, 6 Sep 2020 12:31:42 +0100, newshound

Post by newshound

Post by Cursitor Doom

Post by F Murtz

Post by Cursitor Doom
Gentlemen,
I've run out of the ideal 90:10 mix of argon and CO2 for mild steel
and was wondering if Nitrogen could be pressed into service as an
expedient, given how long it takes for gas to be delivered currently.
I have a nearly full half-size cylinder of pure nitrogen and it would
be handy to say the least if it would make a workable substitute as an
inert gas.
Any thoughts?
CD

Just use straight CO2

Ain't got nun. All I have here currently is a full sized cylinder of
UHP Hydrogen and a half-sized N2; both full.

Get a reel of cored wire?

Well I was wondering about that stuff, Newsy. I know it creates extra
splatter compared to shielded, but that wouldn't matter in this case.
But isn't it a bit too much like normal arc/stick welding? And if so,
it's going to blow holes in the typically 0.7-0.8mm mild steel used
for car sills and other structural areas like outriggers, surely?

I gave away an inherited transformer stick welder before I bought the
MIG, I couldn't do a thing with it which is doubtless down to my lack of
technique.

I did manage to fix a (non structural) hole in a Diahatsu panel once
with gasless MIG. Not terribly neatly. I've done better on more
favourable materials though.

TBH I have not had the MIG out since I bought a little Lidl inverter
welder for stick, I've been surprised how well I can re-fill the holes I
sometimes make with it. As the You-tube videos for the generic ones
confirm, the displayed amps are a bit optimistic but it's fine for one
stick size down from the claimed maximum. Definitely a nice toy to have.

But these days the cars go to a mate who owns a garage.

[Cursitor Doom]

On Sun, 6 Sep 2020 15:43:27 +0100, newshound

Post by newshound
I gave away an inherited transformer stick welder before I bought the
MIG, I couldn't do a thing with it which is doubtless down to my lack of
technique.
I did manage to fix a (non structural) hole in a Diahatsu panel once
with gasless MIG. Not terribly neatly. I've done better on more
favourable materials though.
TBH I have not had the MIG out since I bought a little Lidl inverter
welder for stick, I've been surprised how well I can re-fill the holes I
sometimes make with it. As the You-tube videos for the generic ones
confirm, the displayed amps are a bit optimistic but it's fine for one
stick size down from the claimed maximum. Definitely a nice toy to have.
But these days the cars go to a mate who owns a garage.

It's still very handy to have a heafty arc welder, though. I keep a
trolley-mounted 320 Amp Olympic oil cooled job made in England in 1973
(and still going strong) in the workshop for the big stuff. You can't
beat it for heavy structural work like RSJs. I know you can do thick
plate with MIG, but to match the penetrating power of a stick welder
at that end of the scale you'd have to spend a small fortune on a MIG
big enough to cut the mustard.

[Jimk]

Post by Cursitor Doom
On Sun, 6 Sep 2020 15:43:27 +0100, newshound

Post by newshound
I gave away an inherited transformer stick welder before I bought the
MIG, I couldn't do a thing with it which is doubtless down to my lack of
technique.
I did manage to fix a (non structural) hole in a Diahatsu panel once
with gasless MIG. Not terribly neatly. I've done better on more
favourable materials though.
TBH I have not had the MIG out since I bought a little Lidl inverter
welder for stick, I've been surprised how well I can re-fill the holes I
sometimes make with it. As the You-tube videos for the generic ones
confirm, the displayed amps are a bit optimistic but it's fine for one
stick size down from the claimed maximum. Definitely a nice toy to have.
But these days the cars go to a mate who owns a garage.

It's still very handy to have a heafty arc welder, though. I keep a
trolley-mounted 320 Amp Olympic oil cooled job made in England in 1973
(and still going strong) in the workshop for the big stuff. You can't
beat it for heavy structural work like RSJs. I know you can do thick
plate with MIG, but to match the penetrating power of a stick welder
at that end of the scale you'd have to spend a small fortune on a MIG
big enough to cut the mustard.

240v where you are?

[Cursitor Doom]

On Sun, 6 Sep 2020 18:35:52 +0100 (GMT+01:00), Jimk

Post by Jimk

Post by Cursitor Doom
On Sun, 6 Sep 2020 15:43:27 +0100, newshound

Post by newshound
I gave away an inherited transformer stick welder before I bought the
MIG, I couldn't do a thing with it which is doubtless down to my lack of
technique.
I did manage to fix a (non structural) hole in a Diahatsu panel once
with gasless MIG. Not terribly neatly. I've done better on more
favourable materials though.
TBH I have not had the MIG out since I bought a little Lidl inverter
welder for stick, I've been surprised how well I can re-fill the holes I
sometimes make with it. As the You-tube videos for the generic ones
confirm, the displayed amps are a bit optimistic but it's fine for one
stick size down from the claimed maximum. Definitely a nice toy to have.
But these days the cars go to a mate who owns a garage.

It's still very handy to have a heafty arc welder, though. I keep a
trolley-mounted 320 Amp Olympic oil cooled job made in England in 1973
(and still going strong) in the workshop for the big stuff. You can't
beat it for heavy structural work like RSJs. I know you can do thick
plate with MIG, but to match the penetrating power of a stick welder
at that end of the scale you'd have to spend a small fortune on a MIG
big enough to cut the mustard.

240v where you are?

Yup, but it can be unreliable at times so I have a gennie which does
single and 3 phase.