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MattiJ
03-19-2019, 05:09 PM
https://i.imgur.com/0FjyUbbl.jpg

Can anyone identify the material?
Some type of high temp alloy, part shown has been sitting at 1000C for hours with temporary excursions to over 1200C and there is not even loose scale on it. Oxidises to light brown color. Inconel crumbles to dust in same timeframe.
Machines like butter (also much different from Inconel and relatives) and welds in a peculiar way: TIG Weld bead is super "flow-able" like water and always bright without any oxidation colors. And cracks really easily when cooling down?
edit: strongly attracted by magnets too.

Guido
03-19-2019, 05:26 PM
Here 'ya go------------https://www.enginebuildermag.com/2005/12/valve-selection-hot-valve-materials-for-hot-engines/

MattiJ
03-19-2019, 05:45 PM
Here 'ya go------------https://www.enginebuildermag.com/2005/12/valve-selection-hot-valve-materials-for-hot-engines/

I'm guessing that this could be actually some sort of Kanthal resistance wire relative but I have no experience how Kanthal would machine or weld. Google wasn't too wordy about that either.

nickel-city-fab
03-19-2019, 06:19 PM
Why do you say that Inconel crumbles? I routinely use it at work at temperatures of 1100C for *years* before it fails, in an atmosphere of H2 and Nitrogen. When I use it, there is no oxidation -- weld with argon back purge.

The fact that your part cracks when cooling makes me think it has a lot of chrome. What alloys have lots of chrome? A 400- series stainless? Those are magnetic.

MattiJ
03-19-2019, 06:24 PM
Why do you say that Inconel crumbles? I routinely use it at work at temperatures of 1100C for *years* before it fails, in an atmosphere of H2 and Nitrogen. When I use it, there is no oxidation -- weld with argon back purge.

Normal "room air" atmosphere in this case

nickel-city-fab
03-19-2019, 06:42 PM
Normal "room air" atmosphere in this case

The outside of the tubes I use are in normal room air at 1100C. The inside has H2. No problems or crumbling. I wonder if your part is a 400 series stainless? I bet it is.

MattiJ
03-19-2019, 06:57 PM
The outside of the tubes I use are in normal room air at 1100C. The inside has H2. No problems or crumbling. I wonder if your part is a 400 series stainless? I bet it is.
Only thing that matches 400-series is the magnetic.
Welds totally different from any stainless I know of

nickel-city-fab
03-19-2019, 07:23 PM
Only thing that matches 400-series is the magnetic.
Welds totally different from any stainless I know of

I can't help but think it must be some kind of chrome alloy. Or a high-alloy tool steel? Stellite?

darryl
03-19-2019, 09:21 PM
What did that part do in its other life?

macona
03-19-2019, 09:55 PM
I could probably take a chip of it and EDX it and tell you what it is.

wierdscience
03-19-2019, 11:01 PM
Hi-temp capable and still machines good?

Most likely Cantaffordium alloy ;)

shampine1
03-19-2019, 11:11 PM
Kanthal is available in tubes and is weldable. Looked into it at one point.

Sent from my SAMSUNG-SM-G891A using Tapatalk

MattiJ
03-20-2019, 02:02 AM
What did that part do in its other life?

Calibration oven temperature equalizing block. Solid bar with two 6mm holes.
Nowadays bored hollow, used as pyrometer calibration blackbody..

darryl
03-20-2019, 03:08 AM
I thought I was getting close when I read 'type of metal' in this article I was reading about black body radiators, etc. One spec figure was 1200C, another referenced a shape longer than wide, which can be tubular. But there was no further talk about the metal itself. It only makes sense that the metal specified can't be breaking down at temperatures that high (which isn't particularly high) and decaying in any way. I would have to say it's an exotic alloy, and is liable to contain elements to stabilize it's performance in this unique application. That could possibly be a 10,000$ part- not now probably, but could have been when it was new.

markx
03-20-2019, 03:44 AM
The list of ferromagnetic metals is actually rather short: Nickel, Iron, Cobalt and a few exotic ones like Dysprosium and Gadolinium. Of course the combination of alloys that are susceptible to magnetic behavior is very wide, but the presence of these ferromagnetic components in appreciable amounts is usually required for the alloy to display strong attraction towards magnets.
What is curious is the mentioned softness and good machinability of the material. Alloys with Ni Co content usually are rather tough to machine. High Ni content alloys may be especially troublesome in that sense.
I guess the easiest way to clarify the situation would be to perform EXD analysis on the alloy. Also one could test in which range the Curie temperature of the alloy lies (at which temperature it looses attraction to magnets). This may narrow down the selection a bit.
The piece may contain some exotic components that are harmful, so as long as one does not know the composition, I would revert from performing welding, grinding and cutting on the piece.

MattiJ
03-20-2019, 03:45 AM
I thought I was getting close when I read 'type of metal' in this article I was reading about black body radiators, etc. One spec figure was 1200C, another referenced a shape longer than wide, which can be tubular. But there was no further talk about the metal itself. It only makes sense that the metal specified can't be breaking down at temperatures that high (which isn't particularly high) and decaying in any way. I would have to say it's an exotic alloy, and is liable to contain elements to stabilize it's performance in this unique application. That could possibly be a 10,000$ part- not now probably, but could have been when it was new.

Not 10 000$ part but expensive nonetheless. Blank equalizing block insert with no holes ~500usd, ready made blackbody "cavity" much like shown in first picture ~3000 usd.