Wrong GAS - Cronigon 15

[Nerkus]

Hi mates,

I'm work in a worshop and our speciality is pharmaceutical equipments and today we a "little problem " .... <-- joke.

One welder was welding with Cronigon 15 - stainless steel 304L with steel S275JR ... MIG system and filler weld 307.



The weld doesn't have porosity....amazing and not fisures...how much critical is this weld? Could it broke? The equipment works -1/+3 bar and this weld is the stiffeners with jacket.


Thank you so much and sorry by my English.

 

[Pete.]

Welcome Nerkus.

If your equipment is subject to pressures then your designer is the person to ask that question. The welds have no penetration there from looking at the pics.

 

[Brad93]

Why on earth would you use 307 wire to weld S275 to 304L.

Welds look fine to me, the craters seem to have sunk in okay. They're black as hell though and sooty, likes like your welder hasn't bothered to clean the paint away.

 

[Brad93]

Looked up the data sheet. Cronigon 15 is 60% argon, 38% Helium, 2% CO2.


That's a seriously speedy and hot gas mixture. You must be welding some thick parts usually.

It would be the equivalent to Stainshield Heavy here if I remember correctly.
ISO 14175-M12-ArHeC-38/2

 

[Nerkus]

Why on earth would you use 307 wire to weld S275 to 304L.

Welds look fine to me, the craters seem to have sunk in okay. They're black as hell though and sooty, likes like your welder hasn't bothered to clean the paint away.

Hi Brad...according our welding procedure when we weld group 8 with group 1 is necessary to use this wire.
The weld is fine but I don't know what happens when the gas is wrong.

Thanks

 

[Nerkus]

Welcome Nerkus.

If your equipment is subject to pressures then your designer is the person to ask that question. The welds have no penetration there from looking at the pics.

The designer person is a new engineer... he says that is wrong without explain us a reason...
The weld is a fillet welding without chamfer...it's a stiffener for vacuum. It is our ninth equipment and we have welded others fine but in this case we had this failure..aaaaahne.

 

[Brad93]

Look if you're going to question our logic on an Internet forum, then you need to seek professional advice from a welding engineer or an EWE/IWE.

There's nothing wrong with the gas you're using except it's probably overkill unless the stainless you are welding is over 10mm thick.
Using a heavy gas, one with a large amount of helium can lead to grain growth if I remember correctly.

307 isn't the right wire in my opinion. It should be 309. 307 leaves an austenitic deposit high in manganese very ductile. It is usually used for joining wear plate to steel, 12% Mn wear plate.

 

[Brad93]

The designer person is a new engineer... he says that is wrong without explain us a reason...
The weld is a fillet welding without chamfer...it's a stiffener for vacuum. It is our ninth equipment and we have welded others fine but in this case we had this failure..aaaaahne.

Probably because your welder has been lazy been lazy and not ground the paint off

 

[Brad93]

307 is crack resistant. More so than 309 if I remember correctly. Manganese is a austenite promoter if I remember correctly so the deposit should be highly corrosion resistant even when alloying with the steel. Perhaps That's the reason for the choice.

Still though, 307 work hardens, that can be an issue in many cases.

 

[Nerkus]

Look if you're going to question our logic on an Internet forum, then you need to seek professional advice from a welding engineer or an EWE/IWE.

There's nothing wrong with the gas you're using except it's probably overkill unless the stainless you are welding is over 10mm thick.
Using a heavy gas, one with a large amount of helium can lead to grain growth if I remember correctly.

307 isn't the right wire in my opinion. It should be 309. 307 leaves an austenitic deposit high in manganese very ductile. It is usually used for joining wear plate to steel, 12% Mn wear plate.

Brad accept my apologies please.
It s not my intention question your logic...maybe my English confuse you. We are investigating on all sites and it's a critical situation by us because the welder was welding during 4 days and now whrn He has change gas bottle he saw this mistake.

And yes...this welder is some lazy...

The 307 is the wire indicated by design engineer ( customer ) we cannot change that but your comment will be commented in our meeting thanks sir. All information and comments will be accepted.

Thank you

 

[Nerkus]

Still though, 307 work hardens, that can be an issue in many cases.

Mmmmm I dont like this comment... could be a problem

 

[Munkul]

Brad accept my apologies please.
It s not my intention question your logic...maybe my English confuse you. We are investigating on all sites and it's a critical situation by us because the welder was welding during 4 days and now whrn He has change gas bottle he saw this mistake.

And yes...this welder is some lazy...

The 307 is the wire indicated by design engineer ( customer ) we cannot change that but your comment will be commented in our meeting thanks sir. All information and comments will be accepted.

Thank you

Ah, so you have a load of work done by this gas by mistake and you need to know if it might fail?

Safest way to do it is to qualify the welds by creating a new weld procedure using this gas and settings, do a test piece and get it inspected and tested. If it passes all the tests then you can use this weld procedure.

If it doesn't pass, you'll have to rework all of the welds, unless your designer and inspector say it's not critical.

Not grinding off the paint is a really lazy move, your workshop supervisor should have caught that.

 

[Pete.]

If the welder is that lazy he doesn't clean the paint properly you should put a hold point in the procedure so all parts can be checked by his supervisor before welding. Then start looking for another welder because that guy is a liability.

 

[500e]

What would be the best wire if not 307/9 ? Surely work hardening & cracking go together
If the equipment works -1/+3 bar and this weld is the stiffeners with jacket, ideal conditions for work hardening

 

[Munkul]

What would be the best wire if not 307/9 ? Surely work hardening & cracking go together
If the equipment works -1/+3 bar and this weld is the stiffeners with jacket, ideal conditions for work hardening

To be work hardened, it has to be deformed plastically, and a pressure vessel designed to code should never exceed the yield stress of the material. So work hardening shouldn't be an issue... probably.