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

On 04/09/2020 21:04, Cursitor Doom wrote:
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/

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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On 04/09/2020 21:04, Cursitor Doom wrote:
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/

On 04/09/2020 22:15, Peter Hill wrote:
On 04/09/2020 21:04, Cursitor Doom wrote:
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.

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

On 04/09/2020 22:15, Peter Hill wrote:
On 04/09/2020 21:04, Cursitor Doom wrote:
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.

On 05/09/2020 14:34, Cursitor Doom wrote:
On Sat, 5 Sep 2020 10:35:17 +0100, newshound
wrote:

On 04/09/2020 22:15, Peter Hill wrote:
On 04/09/2020 21:04, Cursitor Doom wrote:
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 isnt actually a pure gas, its 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).

On 05/09/2020 21:45, newshound wrote:
On 05/09/2020 14:34, Cursitor Doom wrote:
On Sat, 5 Sep 2020 10:35:17 +0100, newshound
wrote:

On 04/09/2020 22:15, Peter Hill wrote:
On 04/09/2020 21:04, Cursitor Doom wrote:
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 isnt actually a pure gas, its 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/

On 5/9/20 6:04 am, Cursitor Doom wrote:
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

On Sun, 6 Sep 2020 19:50:03 +1000, F Murtz
wrote:

On 5/9/20 6:04 am, Cursitor Doom wrote:
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.

On 06/09/2020 11:50, Cursitor Doom wrote:
On Sun, 6 Sep 2020 19:50:03 +1000, F Murtz
wrote:

On 5/9/20 6:04 am, Cursitor Doom wrote:
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?

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

On 06/09/2020 11:50, Cursitor Doom wrote:
On Sun, 6 Sep 2020 19:50:03 +1000, F Murtz
wrote:

On 5/9/20 6:04 am, Cursitor Doom wrote:
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?

On 06/09/2020 12:44, Cursitor Doom wrote:
On Sun, 6 Sep 2020 12:31:42 +0100, newshound
wrote:

On 06/09/2020 11:50, Cursitor Doom wrote:
On Sun, 6 Sep 2020 19:50:03 +1000, F Murtz
wrote:

On 5/9/20 6:04 am, Cursitor Doom wrote:
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.

On Friday, September 4, 2020 at 9:04:44 PM UTC+1, Cursitor Doom wrote:
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
The use of nitrogen would produce various oxides of nitrogen, some of them deadly poisons.