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Mystery high temperature material identification?

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  • Mystery high temperature material identification?



    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.
    Last edited by MattiJ; 03-19-2019, 05:13 PM.

  • #2
    Here 'ya go------------https://www.enginebuildermag.com/2005/12/valve-selection-hot-valve-materials-for-hot-engines/

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    • #3
      Originally posted by Guido View Post
      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.

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      • #4
        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.

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        • #5
          Originally posted by nickel-city-fab View Post
          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

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          • #6
            Originally posted by MattiJ View Post
            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.

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            • #7
              Originally posted by nickel-city-fab View Post
              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

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              • #8
                Originally posted by MattiJ View Post
                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?

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                • #9
                  What did that part do in its other life?
                  I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                  • #10
                    I could probably take a chip of it and EDX it and tell you what it is.

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                    • #11
                      Hi-temp capable and still machines good?

                      Most likely Cantaffordium alloy
                      I just need one more tool,just one!

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                      • #12
                        Kanthal is available in tubes and is weldable. Looked into it at one point.

                        Sent from my SAMSUNG-SM-G891A using Tapatalk

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                        • #13
                          Originally posted by darryl View Post
                          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..

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                          • #14
                            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.
                            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                            • #15
                              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.

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