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  1. SMF1964

    7050 Aluminum Alloy Microstructure

    Thanks for the suggestions. My copies (the Red volumes) don't have microstructures in the HT volume (Vol 4) and the metallography & microstructures only have 3 images, from plate. I'll dig around for the AMS spec literature.
  2. SMF1964

    7050 Aluminum Alloy Microstructure

    Does anyone have a reference I can access that will show the microstructure for 7050 aluminum (T7452 heat treated condition)? I have an impeller reportedly machined from a forged 'billet' and would like to compare the microstructure I have with what is typical for this condition.
  3. SMF1964

    416 Stainless Steel Heat Treatment Question

    The studs appear to be in the annealed condition.
  4. SMF1964

    416 Stainless Steel Heat Treatment Question

    Metengr, I'm leaning towards improper heat treatment, with the harder stud coming from a different heat/manufacturer. As for why this material was used, this is a failure analysis project - three studs, all broken, with two fatigue failures at one end and one overload (microvoid coalescence) on...
  5. SMF1964

    416 Stainless Steel Heat Treatment Question

    A582 lists HB 285 max which is ~RC 29 if my conversion table is correct.
  6. SMF1964

    Boiler tube crack

    Could this be a strain-age embrittlement from the forming process of the flange if the forming process was done cold?
  7. SMF1964

    416 Stainless Steel Heat Treatment Question

    I have three studs made from 416 stainless steel, consistent with ASTM A582. Two of them have a hardness of ~RB 90 while the third has a hardness of RB 99. Similarly, tensile specimens machined from these three studs have a tensile strength of 87 ksi vs 105 ksi. The two lower strength bolts...
  8. SMF1964

    Etching Alloy 625

    I've had good luck with 10% Oxalic Acid, but something odd tends to deposit on the polished surface, a crystalline deposit of some sort. Using a plastic "miniature turkey baster" to keep the solution flowing on the surface keeps it from building up and messing up the etch. Mixed Acids etch (my...
  9. SMF1964

    Diluted Weld Deposit Chemical Analysis

    To answer the original question, we've seen iron dilutions up to 20% Fe content in the weld overlay made using a nickel alloy that contained less than 6% Fe in the original wire. Since it was a weld overlay, it's not a matter of getting compositional data from the surrounding base metal because...
  10. SMF1964

    Diluted Weld Deposit Chemical Analysis

    Brimstoner, Please explain: you cannot report the approximate readings for individual elements? The software in my portable XRF unit provides a breakdown of detected elements. If these values are not accurate, how is the system differentiating between, say T9 (9Cr-1Mo) and T91 (9Cr-1Mo-¼V)...
  11. SMF1964

    Admiralty brass and Chloride water

    My house has copper piping, with a water softener that puts 250 ppm chloride into the water as it comes in (the ion exchange process removes the 250 ppm calcium/magnesium). So far, it's held up pretty well. But then, as MetalGuy said, I'm not putting sodium hypochlorite into my water - that's...
  12. SMF1964

    Etching 304ss - x20

    The two replicas may be the way to go. Are you electropolishing for the surface prep or mechanical polishing? If you are electropolishing, couldn't you use the electrolyte as your electrolytic etch? I've done it with stainless steel and with nickel-based weldments, but not yet tried it on...
  13. SMF1964

    Help Indentify Tool Steel /Stainless Steel

    Were it not for the carbon content, it looks like the ferritic stainless SHOMAC 30-2 that's listed in my copy of the Metals Handbook. Add a carbide coating?
  14. SMF1964

    about stainless steel out doors

    It's not so much the change in size but how much constraint there is to that change in size. It does not take much change in size to ramp up the stress if that change is constrained. For example, if we use 30E6 psi for young's modulus, 17.3E-6 in/in/°C for the thermal expansion coefficient of...
  15. SMF1964

    Steel is an alloy

    To quote a famous former President, "It all depends on what the meaning of the 'is' is." Well, in this case, define the connotation of the word "alloy". Do you mean "alloy" as opposed to "pure metal"? Then yes, steel is an alloy. Do you mean "alloy" as in "a specific, unique recipe of...
  16. SMF1964

    about stainless steel out doors

    That is a distinct possibility. You could have bowing if you have different materials for the side rails that have a different thermal expansion coefficient. Heat transfer differences between the edges and the middle of the slide where the edges cool faster than the middle would also give you...
  17. SMF1964

    Stainless/Aluminum Corrosion

    I assume this is outside? If so, then I'm thinking that an alternative to CoryPad's thought (embedded iron) that you're dealing with water coming off of the bricks during a rain storm and carrying with it material from the bricks, mortar, etc., onto the stainless steel. CoryPad: would...
  18. SMF1964

    hardening of 4340 for ultimate strength

    High strength usually goes hand-in-hand with lower toughness. Before you build this, I would strongly suggest that a fracture mechanics analysis is needed to determine the critical flaw size for the material/strength conditions. Heat treating your materials to that high a hardness (Rc 54) will...
  19. SMF1964

    Chilled Water System Corrossion Protection

    If you have a conductivity of 200 milliSiemens and a pH of 9.5, then you do not have demineralized water in your system, even though you started with demin water initially. I suspect that with the mixture of alloys in your system (copper, stainless, cast iron, steel) that you have a galvanic...
  20. SMF1964

    Non-Chemical Etching of Stainless Steel

    Just a thought - If you wave a torch over the surface, would you get a different heat tint from the weld vs the base metal? of course, that could alter the heat treatment of the steel and create other issues, but the process is "non-chemical".

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