NS Dev
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| posted on 10/1/08 at 06:45 PM |
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welding 304 stainless
just about to order a load of hygienic fittings and was going to order 304 ones, but just realised its 304 not 304L........
They will be used for a bike engine exhaust system, do I need to go for 316L or will 304 ( "non-L" ) be ok?????
I ask cos the choice is 304 or 316L............
cheers
Nat
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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mcerd1
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| posted on 10/1/08 at 07:23 PM |
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don't know anything about using them in exhausts (sorry)
but I do know something about using them structuraly (ie not at exhaust temps)
"Grade 1.4401 [316] is also widely used; it contains moybdenum in addition to chromium and nickle, which enhances its resistance to pitting and
crevis corrosion."
"In the past, grades 1.4301 [304] and 1.4401 [316] had significantly higher carbon levels, with implications for corrosion behavior. Either the
'L' grade, or a stabilised steel such as 1.4541 [321] had to be used where there was concern about corrosion performance in the as-welded
condition
However, using modern steelmaking methods, the standard carbon austenitic grades now have carbon contents of 0.05% or below, so the grade distinction
is less important. The presence of weld heat tint is more likely to be a cause of corrosion attack in the welding than any effect of the carbon
content slightly exceeding that of the 'L' grades. However 'L' grades remain the preferred choise for optimum corrosion
performance after welding."
structural design of stainless steel - SCI
grades:
304 = 1.4301
304L = 1.307
316 = 1.4401
316L = 1.4404
IMHO, basically any grade will work but how long do you want it to stay looking good for - the higher the grade the better
I'd go for the 316L if it isn't too much more ££, but more for the 316 than the 'L'
-Robert
[Edited on 10/1/08 by mcerd1]
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907
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| posted on 10/1/08 at 07:29 PM |
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Hi Nat,
I would use 316L for manifolds and down to the collector as it withstands the heat better and is less likely to crack.
From the collector onwards it matters less.
It goes without saying that 316 filler wire should be used for 316 and for 316 to 304.
304 to 304 is welded with 308 wire.
When I bought the bends for Epona there was only 50p difference per bend so I got all 316L although the cans will be 304L.
HTH
Cheers
Paul G
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Simon
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| posted on 10/1/08 at 08:00 PM |
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I used 316L butt weld pipe
ATB
Simon
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Peteff
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| posted on 10/1/08 at 08:10 PM |
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The L is lower carbon, the welds shouldn't discolour as much and will probably be less prone to cracking.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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welderman
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| posted on 10/1/08 at 08:43 PM |
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Grade 316L stainless all the way, i work with the stuff too. 
Thank's, Joe 
I don't stalk people
http://www.locostbuilders.co.uk/forum/23/viewthread.php?tid=172301
Back on with the Fisher Fury R1
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NS Dev
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| posted on 10/1/08 at 09:11 PM |
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ok will play safe and go for 316 then!
for a dry sump tank will 304 sheet be ok or should I be using 316 there too?
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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oadamo
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| posted on 10/1/08 at 09:49 PM |
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quote:
Originally posted by NS Dev
ok will play safe and go for 316 then!
for a dry sump tank will 304 sheet be ok or should I be using 316 there too?
304 is used for tanks and food containers.so its
perfect for the job.
adam
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welderman
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| posted on 10/1/08 at 09:59 PM |
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304 should be ok for tank, as said used for food etc, we use the 316L for the water industy so its the proper stuff.
Thank's, Joe
I don't stalk people
http://www.locostbuilders.co.uk/forum/23/viewthread.php?tid=172301
Back on with the Fisher Fury R1
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paddler20
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| posted on 10/1/08 at 11:25 PM |
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dry sump tank should be ally !!!
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Doug68
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| posted on 11/1/08 at 01:50 AM |
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Not that I've got to the stage yet, but I've read when welding stainless tube the inner needs to be purged with Argon too, or it will
"Sugar" and eventually crack in service.
Is this actually the practical case?
And to run more than one Argon line I assume people run more than one regulator on a 'Y' piece on the bottle or some other method?
Doug. 1TG
Sports Car Builders WA
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thomas4age
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| posted on 11/1/08 at 10:13 AM |
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Nah 2 regulators doesn't seem neccesary,
the proff welders at the factory my brother works the put a T-piece in the line from the regulator to the machine, en run the other branch of the T
into a wood plug which they jam in to the end of the tube, the other end of the tube also gets a wood plug but with a small hole (4-5mm) in it. they
then position the plug with the hole at the highest point, since argon is heavier than air it will then fully fill up the tube, this technique is
called: Backgassing
thing is that for filling up the tube you'd need quite some gas, and you cannot really measure when the tube is full, unless you discard the
hole on the other side, but if presure builds up the gas is likley to break through the weldpool and make a mess.
this is what i've heard and seen from a team of 130+ proffesional welders, not my own experience.
Grtz Thomas
If Lucas made guns, Wars wouldn't start either.
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NS Dev
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| posted on 11/1/08 at 11:30 AM |
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quote:
Originally posted by paddler20
dry sump tank should be ally !!!
no doubt it should but my ally welding aint good enough yet, and off the shelf tanks are no good.
Besides, the std engine was dry sumped on the bike and that used a steel tank so stainless will do just fine. Will be using thinner steel than the
ally would be so not that much heavier in practice, just a bit less heat dissipation.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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NS Dev
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| posted on 11/1/08 at 11:33 AM |
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quote:
Originally posted by Doug68
Not that I've got to the stage yet, but I've read when welding stainless tube the inner needs to be purged with Argon too, or it will
"Sugar" and eventually crack in service.
Is this actually the practical case?
And to run more than one Argon line I assume people run more than one regulator on a 'Y' piece on the bottle or some other method?
I have welded with and without backgas.
I have had cracks with and without backgas!
If you are welding something safety critical, backgas it. If not try it without. I rarely bother now even though I know its not right.
If you get your fitups just right then the exposed section of weld on the rear is tiny anyway, the "sugar" is very limited.
(now waits to be shot down by the pro's!!! eeekk!! )
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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thomas4age
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| posted on 11/1/08 at 11:34 AM |
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well if the tank is sufficiently rust proofed you should be ok, that's the only con I can think of, alloy corrosion absorbs oil and stays put,
whereas steel corrision will be taken up by the engine oil, reentering you're engine, maybe he was pointing to that.
if cooling is the problem the rad aint big enough
grtz Thomas
If Lucas made guns, Wars wouldn't start either.
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