search  current discussion  categories  techniques - stains 

questions about welding stainless steel...

updated wed 27 dec 06

 

Kathy Rhoades on sun 24 dec 06


Paul,
Merry Christmas! Just checked my mail before I call it a night and I saw y=
ou questions. My husband is a welder and I thought I could find out the an=
swers to your questions. He said you are correct, you can weld mild steel =
with stainless rods but you can't weld stainless with mild steels rods. He=
also said that you are doing everything right, but he suggests that you ke=
ep testing on scrap metal increasing your amperage until you burn a whole t=
hrough your metal and then back off 25-50 amps. If you do that you will kn=
ow how far to push your metal without destroying your welds. Hope this hel=
ps.
=20
Kathy Rhoades from PA

=20

> Date: Sun, 24 Dec 2006 14:45:54 -0500> From: PAUL@DOCRET.COM> Subject: Qu=
estions about welding stainless steel...> To: CLAYART@LSV.CERAMICS.ORG> > I=
am trying to finish a large clay mixer i stared a couple years ago and> al=
most finished, but then put on hold for various reasons. It is similar to> =
a bluebird but built to mix batches at least 400 lbs, maybe more; 5 hp TEFC=
> motor with reversing starter and all stainless inside. The tub is finishe=
d> and already mounted on the main shaft and assembled to the frame with bo=
th> sets of bearings, etc.> All the welding that is left is the most heavy =
duty stuff - the ribbons> attached to the shaft and the stops that will con=
trol how far the tub tips> in each direction.> the main questions are, firs=
t of all, the 5/16" 316 L stainless welding> rods i have seem to lay a very=
nice weld even on the mild steel frame - i> just seem to do better with th=
em then the 6011 and 6013's i have,> especailly on thicker steel. I have he=
ard you can weld mild steel with> stainless rods just fine but you can't do=
the opposite. Is this correct?> also, does anyone know what the minimum an=
d maximum amps you need to get> the best welds on stainless with rods this =
thick? the mixing blades are> going to be under a very heavy load, i have t=
o make sure to get max> penetration with these rods but if i burn through i=
have serious problems.> I was testing them out at about 135 amps, it seeme=
d like i could go higher> but i was not sure how much higher.> thanks,> Pau=
l> > ______________________________________________________________________=
________> Send postings to clayart@lsv.ceramics.org> > You may look at the =
archives for the list or change your subscription> settings from http://www=
.ceramics.org/clayart/> > Moderator of the list is Mel Jacobson who may be =
reached at melpots@pclink.com.
_________________________________________________________________
Get into the holiday spirit, chat with Santa on Messenger.
http://imagine-windowslive.com/minisites/santabot/default.aspx?locale=3Den-=
us=

jonathan edward byler on sun 24 dec 06


the rule of thumb that I learned is that about the max amperage you
need with the 6011 rod is the decimal size of the rod as the
amperage. thus a 1/8" rod is .125" = about 125 amps. I have found a
little bit less works better, but this is probably due to the machine
or the operator not being perfect. that would mean that a 5/16" rod
would need about 312 amps. That seems like a lot to me, but I have
never used a stick welder with more than 1/8" rod before. Never
welded with a stick welder on stainless for that matter. I have a
tig welder for stainless. Gives much cleaner stronger welds.

What is the thickness of the material that you are welding? Are you
measuring the thickness of the welding rods including the flux
(improper), or just the thickness of the metal in the rod (proper).

With both tig and mig welding, you can weld mild steel with stainless
filler, in fact I find that when tig welding with slightly dirty
metal the stainless rod welds with less porosity. You can also weld
stainless with mild steel filler metal, but the question is then why
bother??? the welds will hold, but they will by no means be
stainless/rust free, which is the whole point of stainless in the
first place. I have never stickwelded stainless, or with stainless
rod, but I am pretty sure that the stainless would weld mild steel,
although probably not as ideally as the 6011 or 6013. There is a
reason that these rods are used, and it is due to the alloying
elements being tailored to mild steel. If you have the wrong
alloying elements in the weld, it can make the weld much more brittle
and less ductile than the parent metal, leading to structural
failures. If you want to make sure your welds are structurally
sound, I would be sure to practice and study and learn more about
welding first. It may seem easy to lay a bead, but poor choice of
filler metal, and poor technique can lead to serious problems. my
best advice is to do it by the book until you have a serious grasp as
to the effects of different things on the quality of the weld before
you go about making too many changes to tried and true technique.
Consult the manufacturer of the welding rod to see if it is
compatible with the materials you are trying to weld. If you want to
be sure of getting good penetration, be sure to prepare the metal to
be welded properly. anything over 1/8" thick needs to have the edges
to be welded beveled at about 45 degrees to make the root of the weld
thinner. Also need to leave a proper root gap to assure best
penetration. Multiple passes should only be made once slag and
impurities of previous weld passes have been cleaned thoroughly, and
then only if the filler material is rated for multiple passes on that
particular parent metal (the metal to be welded)

if you have any more questions, I will try and answer them as best I
can.

best,

jon



jon byler
3-D Building Technician
Art Department
Auburn University
Auburn, AL 36849

On Dec 24, 2006, at 1:45 PM, Paul Borian wrote:

> I am trying to finish a large clay mixer i stared a couple years
> ago and
> almost finished, but then put on hold for various reasons. It is
> similar to
> a bluebird but built to mix batches at least 400 lbs, maybe more; 5
> hp TEFC
> motor with reversing starter and all stainless inside. The tub is
> finished
> and already mounted on the main shaft and assembled to the frame
> with both
> sets of bearings, etc.
> All the welding that is left is the most heavy duty stuff - the
> ribbons
> attached to the shaft and the stops that will control how far the
> tub tips
> in each direction.
> the main questions are, first of all, the 5/16" 316 L stainless
> welding
> rods i have seem to lay a very nice weld even on the mild steel
> frame - i
> just seem to do better with them then the 6011 and 6013's i have,
> especailly on thicker steel. I have heard you can weld mild steel with
> stainless rods just fine but you can't do the opposite. Is this
> correct?
> also, does anyone know what the minimum and maximum amps you need
> to get
> the best welds on stainless with rods this thick? the mixing blades
> are
> going to be under a very heavy load, i have to make sure to get max
> penetration with these rods but if i burn through i have serious
> problems.
> I was testing them out at about 135 amps, it seemed like i could go
> higher
> but i was not sure how much higher.
> thanks,
> Paul
>

Paul Borian on sun 24 dec 06


I am trying to finish a large clay mixer i stared a couple years ago and
almost finished, but then put on hold for various reasons. It is similar to
a bluebird but built to mix batches at least 400 lbs, maybe more; 5 hp TEFC
motor with reversing starter and all stainless inside. The tub is finished
and already mounted on the main shaft and assembled to the frame with both
sets of bearings, etc.
All the welding that is left is the most heavy duty stuff - the ribbons
attached to the shaft and the stops that will control how far the tub tips
in each direction.
the main questions are, first of all, the 5/16" 316 L stainless welding
rods i have seem to lay a very nice weld even on the mild steel frame - i
just seem to do better with them then the 6011 and 6013's i have,
especailly on thicker steel. I have heard you can weld mild steel with
stainless rods just fine but you can't do the opposite. Is this correct?
also, does anyone know what the minimum and maximum amps you need to get
the best welds on stainless with rods this thick? the mixing blades are
going to be under a very heavy load, i have to make sure to get max
penetration with these rods but if i burn through i have serious problems.
I was testing them out at about 135 amps, it seemed like i could go higher
but i was not sure how much higher.
thanks,
Paul

Michael Wendt on tue 26 dec 06


Paul,
From my own experience with 1/8" 316L
made by Avesta (I run it at 125 amps),
135 amps is probably close.
Do test welds in various positions
that range from down slope 20 degrees to
horizontal to up slope 20 degrees to
simulate actual weld conditions.
Check the weld appearance, especially
check the edges for undercutting. If the
welds are too hot, stainless starts to
blow away as it gets runny.
More tips:
wear leathers since the slag will pop off
very easily while still branding iron hot.
set up a good ventilation fan because you
will be inside the tub and must assure
clean fresh air.
Get some Welco Anti Spatter Spray and
coat all the internal surfaces prior to welding
to avoid having to grind the spatter off the
inside of the tub. It is usually for weld tips
but works great for this too.
If the rod is old, follow the directions
for oven drying it prior to welding.
Hydrogen from water absorbed during
long term storage can make welds
brittle. Hydrogen is a very light gaseous
metal and forms alloys with other metals.
Watch the rod temperature.
Short runs help prevent the blowing away
and a side to side weave pattern helps
avoid blowing away on thin stock.
On thick stock, be sure to grind the edges
at a 45 degree angle to get into the metal
to be joined further.
Finally, at key points, you can do multiple
passes, just be sure to slag before you make
the next pass.
Congratulations on the mixer. You won't
regret having it and the control of the clay
body it offers.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
Paul wrote:
the main questions are, first of all, the 5/16" 316 L
stainless welding
rods i have seem to lay a very nice weld even on the
mild steel frame - i
just seem to do better with them then the 6011 and
6013's i have,
especailly on thicker steel. I have heard you can weld
mild steel with
stainless rods just fine but you can't do the opposite.
Is this correct?
also, does anyone know what the minimum and maximum
amps you need to get
the best welds on stainless with rods this thick? the
mixing blades are
going to be under a very heavy load, i have to make
sure to get max
penetration with these rods but if i burn through i
have serious problems.
I was testing them out at about 135 amps, it seemed
like i could go higher
but i was not sure how much higher.
thanks,
Paul