TEST RESULTS was re: inconel or stainless

[Ignoramus28785]

I got this oven with grates and a heat exchanger, for scrap, and I am
trying to test if it is inconel or stainless.

Here's a picture of the heat exchanger:

http://www.machinerymoverschicago.com/tmp/heat-exchanger.jpg

So, today I got to work and decided to give the TIG test method a try.

I grabbed a piece of known 300 series stainless steel (large
rectangular piece in the vise on the picture), and cut off two
triangular small pieces from a heat exchanger.

Here you see the exchanger triangles laying on top of the stainless piece:

http://www.machinerymoverschicago.com/tmp/inconel.jpg

First of all the possible inconel pieces are clearly of different
color, you can see one unburned one.

Then, with a TIG torch, and WITHTOU any shielding gas, I tried to burn
both materials. The stainless did exhibit "sugaring" just as the smart
people here said it would.

The small pieces from the heat exchanger changed color, but did NOT
exhibit sugaring.

I also tried to grind both pieces with an angle grinder and they gave
different patterns, the stainless sparks were a lot longer and more
plentiful.

I did not test the large grates.

any thoughts on this?

[dca...@krl.org]

On Sunday, July 24, 2016 at 2:02:25 PM UTC-4, Ignoramus28785 wrote:
>
> I also tried to grind both pieces with an angle grinder and they gave
> different patterns, the stainless sparks were a lot longer and more
> plentiful.
>
> I did not test the large grates.
>
> any thoughts on this?

You could send me a chunk off the grate and I could sweet talk the guy at the scrap yard to use the XRF on it.

You could look on Ebay and get someone else to XRF it. I think most places charge about $25.

Or I could send you a couple of pieces of inconel welding rod so you can check how known inconel acts and sparks. There are more than one inconel, but at least you would know exactly what the welding rod was.

I have no experience with seeing if a metal sugars when heated. I would expert different stainless steel to not all act the same.

Dan

[et...@whidbey.com]

I imagine that the alloy is a high nickle content alloy because then
it would resist oxidation at high heat, which is what you found.
Beyond that I don't know. I'm glad the sugaring test worked out, it's
pretty obvious when it occurs.
Eric

[Ignoramus28785]

Dan, thanks a lot. Let me see if I can sweet talk my friend scrap yard
first, if not maybe I can ask for your help.

i

[Pete Keillor]

I had a pan made out of Hastelloy X once. Expensive stuff. I was
running calcining tests in a lab. The hastelloys may be even more
expensive than inconel. I also had a twin screw extruder made of inconel,
don't remember the alloy. Out of the 15 barrel sections, there was one
combi barrel with side and top feed ports. I remember it was $40,000 in
the mid '90's. This was a 40 mm. machine.

Pete Keillor

[Peter Fairbrother]

I would agree.

Whether it is an inconel, monel, or other ally it is hard to say, though
it does have the look of a nickel-chromium (inconel-type) alloy, the
slightly whitish powdery look it develops is (may be) chromium oxide.

Best way is to test it is energy-dispersive X-ray spectroscopy with an
X-ray fluorescence spectrometer (handheld XRF).

At $25k these are very expensive though, but a good high-tech scrappie
should have one, and would probably test it for a few dollars.
Alternatively you can send a sample off for testing for $20-30.

If it is inconel (or monel) it is worth a bit as scrap. Not as much as
quite a lot of people think or hope, but a rough guide expect about
$3.00 - $4.00 per lb.


-- Peter Fairbrother

[David Billington]

If Iggy can't get a sample tested with a XRF then I had wondered about
suggesting a crude OE spectrometer as I know Iggy has a TIG welder.
Strike an arc on the sample, pass it through a slit and a prism and take
a picture of the resultant colour bands. I expect information on the
visible spectral lines of the likely constituent metals is available on
the internet. Some known samples of steel and stainless steel would help
as a reference and it might at least help get closer to the alloy type.
I know in practice the spectrometers are far more complicated as I used
to write software for both OE and XRF spectrometers.

[edhun...@gmail.com]

That's a good thought, but the composition of Inconel 600 (the most common grade used in furnaces) is identical to that in lower-level 300-Series stainless. The only thing different is the quantities of iron and nickel. (Inconel 600 is 72% nickel; 304 stainless is 8%). The quantities of iron and nickel in each are almost exactly reversed.

You'd need something more than spectral lines to tell them apart.

--
Ed Huntress

[Peter Fairbrother]

On 25/07/16 12:02, Pete Keillor wrote:
[..]

>
> I had a pan made out of Hastelloy X once. Expensive stuff. I was
> running calcining tests in a lab. The hastelloys may be even more
> expensive than inconel.

Hastelloys themself in raw form are only a little more expensive than
Inconels (depends on exact alloy, but roughly speaking) - but they are
even more of a pig to machine.

I have been trying to cut or otherwise part off a 1-1/2" Hastelloy X bar
for about ten years. Gone through I don't know how many bimetal and
carbide hacksaw/bandsaw blades; carbide, ceramic, diamond and CBN
parting inserts ..

> I also had a twin screw extruder made of inconel,
> don't remember the alloy. Out of the 15 barrel sections, there was one
> combi barrel with side and top feed ports. I remember it was $40,000 in
> the mid '90's. This was a 40 mm. machine.

Yep, machined inconel parts are hellova expensive; machining inconel is
a total pain in the butt and many people refuse to do it.

Sadly, scrap inconel isn't that valuable - as I said elsewhere, expect
$3-4 per lb. A lot of the value in Inconel parts is in the forming,
especially if it has to be machined.

One of the first uses of DMLS (direct metal laser sintering, a type of
3D metal printing) in Inconel was a muzzle brake, which despite the
horrible costs of DMLS in Inconel, costs 3/4 of the price of a similar
machined muzzle brake ...




-- Peter Fairbrother

[who fairly regularly machines Inconels and monels, and wishes it was
easier]

[David Billington]

I guess it would depend on how the intensity of the spectral lines can
be discriminated between in that case between different alloys in a
photograph. I know the old OE instruments I wrote software for had photo
multipliers and IIRC connected to the prism chamber with fibre optics
and each photomultiplier was dedicated to a spectral line and the
instruments tended to be set-up to analyse a particular class of
material such as steel and its associated constituent elements. I think
these days things have moved on and CCD sensors are used. The last time
I wrote software for the company was about 7 years ago.

A guy I know locally did some development work on a handheld XRF and
showed me the prototype, apparently it had a 25kV source in it but in
the end it was decided easier or cheaper to buy a company that already
made them but they use a radioactive source IIRC and that can present
transport problem in some jurisdictions. Having seen them I can
understand why they're often referred to as a brick on a stick.

[Ignoramus19696]

sad news... this is 304 stainless

[edhun...@gmail.com]

On Monday, July 25, 2016 at 4:48:33 PM UTC-4, Ignoramus19696 wrote:
> sad news... this is 304 stainless

When you said "catalytic oven," that was my thought. Most of those things are made with an open exhaust and are made for curing paint and powder coatings -- low-temperature stuff.

However, I'm sure there are other kinds. I've just never seen any except the ones used in finishing departments. The catalyst is there to oxidize CO into CO2.

--
Ed Huntress

[dpb]

On 07/25/2016 3:48 PM, Ignoramus19696 wrote:
> sad news... this is 304 stainless

So how did you finally get the determination?

--


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[dpb]

On 07/25/2016 2:43 PM, Peter Fairbrother wrote:
> On 25/07/16 12:02, Pete Keillor wrote:
> [..]
>>
>> I had a pan made out of Hastelloy X once. Expensive stuff. I was
>> running calcining tests in a lab. The hastelloys may be even more
>> expensive than inconel.
>
> Hastelloys themself in raw form are only a little more expensive than
> Inconels (depends on exact alloy, but roughly speaking) - but they are
> even more of a pig to machine.
>
> I have been trying to cut or otherwise part off a 1-1/2" Hastelloy X bar
> for about ten years. Gone through I don't know how many bimetal and
> carbide hacksaw/bandsaw blades; carbide, ceramic, diamond and CBN
> parting inserts ..
>
>
>
>> I also had a twin screw extruder made of inconel,
>> don't remember the alloy. Out of the 15 barrel sections, there was one
>> combi barrel with side and top feed ports. I remember it was $40,000 in
>> the mid '90's. This was a 40 mm. machine.
>
> Yep, machined inconel parts are hellova expensive; machining inconel is
> a total pain in the butt and many people refuse to do it.
>
> Sadly, scrap inconel isn't that valuable - as I said elsewhere, expect
> $3-4 per lb. A lot of the value in Inconel parts is in the forming,
> especially if it has to be machined.

...

Nuclear fuel rod cladding and spacer grids are Inconel for the reduction
in Fe for the purpose of minimizing parasitic neutron capture. B&W NNFD
(Navy Nuclear Fuel Department, sole purveyors of nuclear fuel to USN)
pioneered the use of laser to allow for punching a hole thru the
cladding to pull vacuum and insert the inert fill gas, then one of the
fella's at the Lynchburg Research Center had the bright idea that when
done, all had to do was defocus the laser a little and it welded the
hole back shut...a _much_ simpler and thereby cheaper technique than
trying to backfill then weld on the end cap over the full rod had been
doing up to then. "The Admiral" was most pleased (showing how long ago
this is getting to be by now)...but the technique is still used for
commercial fuel as well.

[Ignoramus19696]

On 2016-07-25, dpb <no...@non.net> wrote:
> On 07/25/2016 3:48 PM, Ignoramus19696 wrote:
>> sad news... this is 304 stainless
>
> So how did you finally get the determination?

XRF gun...

[Jim Wilkins]

<edhun...@gmail.com> wrote in message
news:9e256d8b-7428-4244...@googlegroups.com...

====================

http://www.ursusmajor.ch/downloads/emission-spectroscopy-2.0.pdf

I learned spectroscopy on a ruled grating machine built in the 1930s
that recorded spectra on glass plates. There was a densitometer to
measure the lines but the process wasn't considered very accurate
because the arc source wasn't well controlled.
--jsw

[Martin Eastburn]

Remember the XRF gun is adjustable. If one turns it back
so only % over 10% or 20% all sorts of metal is down graded.

I caught my local guy setting it to 20% and saying AR400F was
A-6 steel. I knew better.

Martin