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Jerrod Miller

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Jerrod Miller last won the day on October 12 2021

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About Jerrod Miller

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    Metallurgist
  • Birthday 03/25/1984

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    Jerrod Miller 25
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    jerrodmiller@hotmail.com

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    Male
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    Near Spokane, Washington
  • Interests
    Steel metallurgy, HEMA, forging (blades and otherwise).

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  1. This is quite interesting stuff. If anyone has a sample of mono-steel that seems to be behaving like the images posted by JT in the second link from billyO (this one) I would be very happy to run it on a spectrometer to see if there are chemistry differences between sections. Needs to be distinct sections of about 1 inch diameter for the spectrometer I currently have access to (I'm vaguely shopping for a new one, but I would bet the requirements will be the same there, too).
  2. That was great, thanks for sharing! While not directly related to the smelting, I loved the riveted poll prior to welding it in place.
  3. I agree that seems most likely. Could be from either, or both.
  4. I feel like I should add that in those temperature ranges there is a curve for carbide precipitation (chemistry dependent). Below a certain temperature and the carbides do not readily form, above a different temperature they will dissolve. I am not familiar enough with this alloy to know the temperature ranges for carbide precipitation. If it had 2.5-3.5% C I could be much more help. I think that the 1950 range is going to be hot enough to dissolve them, and I would bet that the majority of your 1 hour ramp time was on the hotter side. Therefore I would bet that grain growth is the bigges
  5. If you feel like you can get it over 1000F and under about 1450F then a sub-critical anneal of the handle area should soften it up pretty good. No real worry about carbide formation there, you just have to make sure you don't accidentally get some hardening.
  6. As far as I am aware (and I don't get involved heavily on these types of alloys), the pin-hole is really only going to be a matter of a little decarb/scale due to the general lack of air movement over the blade surface, which isn't likely to be too much of an issue. I would be a little more worried about the longer ramp time. I would bet that the result should still be pretty good, if not quite ideal. I would suggest using this blade as one you finish out and abuse simply as a test blade. See how well it retains an edge, both through use and abuse. See how it acts as a pry-bar. Finally b
  7. That is the stuff that gives me a headache to think about too deeply. Metallurgy is soothing compared to circuits.
  8. Hardness is defined as the resistance to plastic deformation. True hardness tests (Rockwell, Brinell, Vickers, Knoop) measure hardness by pressing an indenter of a set size/geometry into a part with a precise load, then measuring the distance it went in or the size of the indent created (depending on method). Harder materials are generally more wear resistant, but more brittle (they fracture rather than deform). For strength and toughness, I find it best to look at a stress-strain curve. Below is the example I pulled from Wikipedia. Stress is the load per area, ge
  9. Or work with the sharp line you would get from just pouring more. Maybe do some file work or inlay to hide it.
  10. Kind-of-sort-of working, but not doing what it is needing to do. The engine is technically running, but you aren't driving anywhere with it. Your vents had gases going through them, but not enough to prevent problems. That is what I was trying to illustrate, and I think the analogy holds. And I have seen engines run with all of those conditions, so it is definitely not absurd from a mechanic's viewpoint either.
  11. Then you want to be about 50-75F above non-magnetic. For normalizing and for hardening. You'll be better off not using the magnet and sticking with watching for decalescence and recalescence.
  12. That is very far from accurate. The best analogy I can think of off the top of my head is a car engine. Just because it turns over doesn't mean you're ready to race with it, or even go to the store. You could be firing on only half your cylinders, broken pistons, out of oil, no coolant, etc. Sure it is technically running, but it is not doing it's job. The old adage on venting is "Vent, vent, and vent some more. When you think you have enough, double it. Now you almost have enough."
  13. That is exactly the problem of having too fine of sand and not proper sand grain size distribution. Your sand should have a certain amount of permeability that allows gas to go through it. You need enough permeability that the gas can go through the sand easier than through the metal. Also, it is important to use no more bonding agent than absolutely necessary.
  14. If you are interested in mixing your own, it is not that difficult. Green sand takes a bit of work to keep the right moisture, but K-Bond is a very nice oil-bonded sand that is very stable and works well for non-ferrous stuff. https://www.afsinc.org/sites/default/files/inline-files/k-bond sand.pdf The key when making your own sand for casting is to have the right distribution of sizes. Finer sand grains means smoother surface, but more binder agent required as well as possible venting issues. I would recommend some where in the AFS GFN (Grain Fineness Number) of around 100. Th
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