Welding 304 S/S exhaust

[chevy2]

I use 316 filler on both 304 and 316 s/s tube on all the exhausts i build,
the exhaust i built on my own car is 304 tube with 316 filler and is a good 10 years old now.

 

[Ben88]

What about using 2205 duplex stainless steel 1.2mm for the filler, i've got 30kg of it. Ive read that it is tougher than stainless an more corrosion resistant so could it be of any use? If not i'll just get some 309L. As for purging i'd rather go that route, i'd of thought purging it would help with the distortion as well keeping it cool. If it takes a full Y bottle to do (an i doubt it would) an he's happy it could lead to more work as the car will be taken to shows cheers for the input

 

[Richard.]

Why 309L?
That's more suitable for dissimilar joints. The exhaust is 304 I assume ? If so weld it with 308 or 316. Which ever you come by easiest and cheapest that'll do the job nicely with an inside purge. Your not going to use a whole bottle purging one exhaust. As Rich M said you can block it up closer to the joint so your not filling the whole system. Just be sure to put a hole in the block to allow the air out.

 

[TechnicAl]

2205 needs to be heat treated after welding..........2209 is the more common Duplex for welding consumables

If its 2209 you could use it

 

[backpurge]

What about using 2205 duplex stainless steel 1.2mm for the filler, i've got 30kg of it. Ive read that it is tougher than stainless an more corrosion resistant so could it be of any use? If not i'll just get some 309L. As for purging i'd rather go that route, i'd of thought purging it would help with the distortion as well keeping it cool. If it takes a full Y bottle to do (an i doubt it would) an he's happy it could lead to more work as the car will be taken to shows cheers for the input

The purging gas won't have a cooling effect, you will only be running around 2 ltr/min once you get your O2 level down, but you should be able to weld slightly faster as bead formation is better, this will reduce the heat input a bit. One thing you do need to watch out for is shrinkage which adds up surprisingly on a component with a lot of joints in it.

 

[chevy2]

The purging gas won't have a cooling effect, you will only be running around 2 ltr/min once you get your O2 level down, but you should be able to weld slightly faster as bead formation is better, this will reduce the heat input a bit. One thing you do need to watch out for is shrinkage which adds up surprisingly on a component with a lot of joints in it.

I'm currently involved with the chassis work on this car but we farmed out all the stainless turbo pipework to a specialist,
He reckoned he'd need to allow a 1/4" for shrinkage with this amount of welding.

 

[Ben88]

Is that 309L 316L or 309 316 what is the difference between these to i read that the L has lower carbon content and that it is used when heat treatment cant be used is that correct? I've never worked with anything that has needed heat treatment is that more common in aero space sector? Would i be able to put like a 2mm gap between each weld to compensate for the shrinkage or would i be better having the parts made slightly bigger? cheers

 

[Richard.]

309L

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Why 309. It's rather an expensive consumable to use on that when it's not needed.

 

[Paul G]

Use your bottle and T off with a Y peace.

You've made my day Richard. Just had to smile.

Paul G

 

[Richard.]

You've made my day Richard. Just had to smile.

Paul G

I read it back after posting and made myself smile aswell.
Wondered who would get there first.

 

[Ben88]

Sorry 308 not 309 was just giving it as an example

 

[Richard.]

Yep 308 is the designed consumable for 304 SS.
The L means lower carbon. I don't suppose it matters too much For an exhaust joint if it's 308/316 or 308L/316L. Like I say 316 is primarily used for welding 316 grade ss. It contains molybdenum too which makes it a little more corrosion resistant as its a marine grade material. Your not going to see this benefit though on an exhaust I doubt as heat tint will come through and cause surface rusting what ever you use. It's strength is higher than 308 so a little less ductile. Never the less both are used for that application and done properly with a backing purge will last you many years. I look forward to seeing the finished result.

 

[Paul G]

Use your bottle and T off with a Y peace.
Richard.

You've made my day Richard. Just had to smile.
Paul G

I read it back after posting and made myself smile as well.
Wondered who would get there first.
Richard


By pure coincidence I broke the top off my flow meter last week so ordered a new pair.
They arrived this morning so I fitted them.

As my Harris has an outlet that faces down at 30 deg I had to Y off with a T to keep them upright.
I thought of you as I did it.

ATB
Paul G

 

[Brad93]

Purging properly is the most important thing. My milltek manifold has cracked because it hasn't been purged where the brackets are.

 

[Richard.]

Use your bottle and T off with a Y peace.
Richard.

You've made my day Richard. Just had to smile.
Paul G

I read it back after posting and made myself smile as well.
Wondered who would get there first.
Richard


By pure coincidence I broke the top off my flow meter last week so ordered a new pair.
They arrived this morning so I fitted them.

As my Harris has an outlet that faces down at 30 deg I had to Y off with a T to keep them upright.
I thought of you as I did it.

ATB
Paul G

I have the luxury of an elga optimator twin flow set up which neither Y or T is needed. That's my excuse for such crap terminology and spelling. . Doubt it is a good excuse though but I'm sticking with it.
Rich.

 

[Richard.]

Purging properly is the most important thing. My milltek manifold has cracked because it hasn't been purged where the brackets are.

Un purged full pen joints will almost certainly fail at some point. Some people think it's just a precaution measure and not always needed. With good backing bars tight up where oxides cannot attack the inside its not always needed. Sugaring is a major defect. Imo it's as bad as face side porosity and we wouldn't stand for that.

 

[langy]

I'll second above. Depending on exactly how big and how much of it your welding it will use a fair amount of argon to purge. The amount of filler used will be minimal. I personally would not opt for the ms joints but that's me I like to do things with correct consumable. Saying that most off the shelfys are done like that with ms filler. I've welded quite a few and 308 is what I've used.
Brad 316 is an expectable filler for 304 exhaust it's just a bit stronger and less ductile so unpurged joints. Are far more likely to crack but I believe @langy only uses this filler for his exhausts and he's done more than I have with no issues.

90% of the systems i've done over the years are 316 but occasionally you get 304 bends come in, I still use 316 wire and have never had a joint failure ever.
I only purge if the customer wants it done, as its another expense


This is a typical system

 

[Tigman]

How many welds in the one side of that Langy ? all polished out ! very nicely done !

 

[langy]

How many welds in the one side of that Langy ? all polished out ! very nicely done !

19 in one side and 22 in the other, cheers bud

 

[Richard.]

19 in one side and 22 in the other, cheers bud

There is no question that's a stunner mate.