Welcome back to TIG Time
I'm mister TIG
Todayís episode is going to be one of the three episodes
on welding stainless steel
Now first of all
What is stainless steelÖ what makes it different from steel?
Well by definition it's chromium content.
So if you have mild steel and you toss in about twelve percent chromium which
makes it tougher
and thus we have the stainless portion of it, or corrosion resistance
Now you have stainless steel
Itís actually easier to weld
if you follow the instructions stainless steel defines real well in the puddle
You could see the puddle real well you can define your dips of adding the
filler material the dabbing
And just so you know there are so many different
types of stainless steel
Weíve come up with the chart for you and you can go on Weld.com
to get this chart
Now I happen to have it
In front of me
I just wanted to find a couple of the stainless steels I mean there's a whole
list of them. Weíve got 304 stainless,
301, 316
Weíve got 321 stainlessÖ
Where does it end?
How do you select
the material that you want to use for your application?
So we're going to start off
with the most common
stainless steel and the most common that you'll find
is typically called the 304
for stainless
When you get ready to weld 304 this chart will also tell you what filler to use
and Iím just going to do a little cross-section here
And Iím getting ready to weld 304
to 304
And the chart tells me to use 308L
filler material
And just so you know, you can weld mild steel to stainless steel again just looked
at the chart
and it will tell you what filler to use
Now, this is the first of three in the series so we're going to weld 304
but we also want to do a little identification. How do I know Iíve got
stainless steel?
And sometimes out in the shop you have stainless and it might be three or four
stainless steel
you're not a hundred percent sure
But a good way of finding out isÖ Iíve got
two samples of material here and Iíve got one
It looks like it's stainless steel because it it's a little bit shinier
so one way to check
is to take a magnet
just a normal magnet
and see if
the magnet will pick it up
And in this particular case the magnet doesnít pick it up so
there's a good chance that this is
stainless steel, there's a lot of chromium in it
Now this
maybe stainless or you know what it may be mild steel
Letís check
OhÖ it's mild steel
So, that's just a quick check
There are all kinds of little checks that you could do
One of them is you can grind the difference between the two and
sometimes you have a keen eye to see the difference sparklers come off
But the magnet is usually the best one to use
Now, one of the concerns I have in welding this material
the chromium
When you get activated, when you get a puddle
Whatís going to happen it is oxygen is going to try to attack
It, so with the TIG torch
we have a gas lens
This particular TIG torch Iíve got a gas lens, a one-sixteenth tungsten
sticking out about a quarter of an inch that's going to be our
standard
and so Iíve got good gas shielding Iíve got a part
set up here and is tacked
At both ends
Iím going to get good gas shielding here and as I weld
Iím going to dab consistently
When I finish the weld
I am going to turn the part over
and you're going to see the penetration
Now if you put
A purging or a gas back up
to this penetration
Youíre going to have an excellent looking weld on the back side
If you didn'tÖ If you took shortcuts
and you didn't put gas backup
Youíre going to find that it welds a little more difficult
and you're going to find oxides on the back side
and these oxides will definitely shorten the life of your weld
Or if you're welding up on of your expensive exhaust parts for a
Race car, a high-performance car
or just about anything
it's going to shorten life
SoÖ just want to let you know stainless steel has its place it's a great material
Itís actually
easy to weld
So we're going to get started and I'm going to run
Half of this plate
without gas backup the second half Iím going to turn the gas back up on
OkayÖ
It initiates very cleanly
you can see that puddle
real shiny
and I'm just
adding a little bit at a time
I can see
That Iím starting to penetrate
And this particular weld does not have gas backup
SoÖ
the likelihood is
There is going to be a few oxides on the back side
And we will show those to you a little bit later
but the top side typically welds pretty nice
AndÖ Iím finishing the weld
Reducing my amperage
and
making sure that the crater does not fill too low.
And weíre finished.
Okay, weíve got arc initiation, you can see the puddle is forming
Itís nice and clean
Now this particular setup has
purging on the back side
Meaning argon gas
SoÖ I actually get a little cleaner weld
And a little more control
It doesnít try to wonder on me
ìA little dab of fillerî
SoÖ very stable, very shiny
And Iím going to finish up here shortly, so Iím going to
Make sure I donít leave a crater crack. I am going to add a little extra filler right at the end.
And you can see Iím only using like 045 diameter
308L
And I get to theÖ
Weld termination
And I pull out of the puddle with amperage
Little lessÖ little lessÖ and Iím finished.
Okay let's take a look at what we just did
Okay now this will write here we added filler material
We had argon on the TIG torch and we did not have purge gas on the back
side
And youíll probably notice there's kind of a burn line here, itís kind of a dirty burn
line
If you move over to do this weld
We also ahead purge gas and
Torch gas at the same time
it does have a burn line
and weíre to cover the later how to get rid of that burn line
But right now we're just comparing the difference between purging
verses not purging your part.
And now Iím going to turn the part
over
And this really is the tell tail sign whether you did it properly or not
This is the oxide sometimes you hear it described as brown sugar
The backside did not wet out well at all so there is going to be non-fusion and because you
have these chromium oxides, cracks are going to start forming and you're going to
have poor performance in your
part or whatever youíre welding. It could be an exhaust system, it could be anything
but it's not going to hold up
as well
as this right here
This has perfect fusion
You can see
that it wetted out very nicely
Now there are all kinds of ways of
purging and we're going to continue those in section two and three of this.
Well that's it for now
Thanks for watching TIG Time
Iím Mr. TIG