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  1. RedVette

    Inconel 718 or 750

    Alloy 718 more suited for this kind of service because of the presence of Mo into its chemistry. Though alloy X-750 can withstand this service, it is the lack of Mo in alloy X-750 that makes it more susceptible to intergranular stress corrosion cracking. The specially limited chemistry version...
  2. RedVette

    What exactly does PREN refer to?

    Wow. You guys have given very informative responses, and I'm still in the process of absorbing these concepts in my mental visualization of the pitting process. Thanks very much to Cloa and EdStainless. Knowing that the pitting phenomena is subcategorized into initiation and propagation helps...
  3. RedVette

    What exactly does PREN refer to?

    Hey, guys. Can someone please clarify whether the PREN value refers to the susceptibility of an alloy to form a corrosion (localized) pit or if it refers to the susceptibility of a given passive oxide film breaking? The reason for my confusion is due to PREN values being used to evaluate both...
  4. RedVette

    What alloy do they use for fuel pump nozzles?

    Hey, Ed. Wow. I previously thought this would require at least grade 316. But if 304L is acceptable for this application, then I guess Inconel would be overkill. Maybe Inconel is only used for nozzles in the aerospace field... Out of curiosity, are the stainless supplies from India acceptable...
  5. RedVette

    What alloy do they use for fuel pump nozzles?

    Hey, guys. Can someone tell me what alloy is used to make the nozzle pipes at the fuel pump? I've read that certain stainless steels are suitable for contact with stagnant gasoline (that gas tanks are sometimes made of stainless), but I've also read that Inconel is used for fuel nozzles. When I...
  6. RedVette

    Molybdenum and Corrosion resistance

    Ed, I understand now that, with the proper balance, Mo improves corrosion resistance by enhancing both the lattice strain as well as the oxide film. However, in conditions where passivity potential is at a minimum, is it the case that the noncorrosive benefit of Mo is obscured in alloys where...
  7. RedVette

    Molybdenum and Corrosion resistance

    I understand that the presence of molybdenum in alloys contributes to greater corrosion resistance in that it "increases the lattice strain," thereby necessitating greater energy to dissolve the iron from the surface. However, what I'd like to know is whether the increase in corrosion resistance...
  8. RedVette

    Accuracy of XRF scanners?

    Thank you guys for clarifying on this matter. Given the density factor, would I be correct to assume that, since carbon is even lighter than Al and Si, it is therefore practically impossible for an XRF to pinpoint its percentage to within any proportionate range of accuracy apart from luck...
  9. RedVette

    Accuracy of XRF scanners?

    Hey, guys. Would any of you happen to know what the accuracy tolerance is with modern XRF alloy scanners? Does it vary by brand? I read a brochure from Niton outlying their advances in the past century--heightened sophistication allowing a wider range of data processing, but it doesn't talk...
  10. RedVette

    ESR vs VAR refining

    When strictly comparing the integrity of nickel and cobalt-based superalloys refined by either electroslag remelting or vacuum arc remelting (excluding triple-melting and powder processing), which is generally the better choice? My brief research showed reports arguing the benefits of both over...
  11. RedVette

    Countries of Origin

    It also occurs to me that the melting furnaces in China can be questionable as to their ability to yield ingots that are as segregation and impurity-free as other counterparts. I think their computer technology has always been on the tail end, so quality control that relies on their critical...
  12. RedVette

    best metal for eyebolt in corrosive enviroment

    If moisture-induced rusting without the presence of strong chlorides or other chemicals, Nitronic 60 (alloy 218) may the economic solution to your problem. Its galling (though not abrasion) resistance surpasses many superalloys, and its antiseizing properties ensures that a tightened thread will...
  13. RedVette

    Countries of Origin

    Places where corner-cutting has been the predominant trend certainly warrants caution against using their products. But this thread has provoked me to think of situations that might make it harder to differentiate. For example, Thyssenkrupp is a notable Germany-based alloys corporation with...
  14. RedVette

    CCW performance between Ultimet & 6B?

    Hey guys. Can someone please tell me whether Carpenter's CCW alloy performs closer to Haynes Ultimet alloy or Stellite 6B? Its chemical composition is nearly identical to Ultimet, except for the fact that the tungsten content is what 6B has and there is a significant tantalum (though no...
  15. RedVette

    Non-corroding non-tarnishing inexpensive lustrous yellow metal gold alternative alloys?

    anon359, If you're looking for something having the qualities you're looking for in addition to durability, aluminum bronze is probably the best bet for you at the current time. I've also been searching for a cheaper, more durable substitute for gold, and copper alloys was the only thing of any...
  16. RedVette

    X-750 vs 718

    Hey guys, Can someone please tell me if there is any notable difference in the all-around performance between nickel alloys X-750 and 718? From the manuals I've read on the Special Metals website as well as numerous other articles, it seems to me like these two alloys are almost identical in...
  17. RedVette

    Sulfidation Question

    Sorry, forgot one alloy: MP159 and HR-160. So altogether, they're alloys 218, 686, MP159, HR-160 and L605. Also, I should mention that the 1400 F condition also includes an equilibrium sulfur partial pressure of 10 -6 (negative six exponent).
  18. RedVette

    Sulfidation Question

    Oh, yes. Alloys, 218, 686 and L605. If subjected to both conditions for the same duration, would all alloys find a same condition more intolerable than the other?
  19. RedVette

    Sulfidation Question

    Hey, guys. Just have a quick question about which of the following sulfidizing conditions is more severe: Ar-5% H2-5% CO-1% CO2-0.15% H2S-0.1% H20 @ 1400° F or 90% na2so4 + 10% kci @ 1600° F Any clarification will be greatly appreciated.
  20. RedVette

    Nitronic 60 in H2SO4

    Unclesyd, Thank you for the valuable information. I never knew about the sulfate solubility dependency on acid concentration. I'll be sure to not forget it. Other than Nitronic 60, I've considered Haynes HR-160, 118, 556, and 254 SMO as alternatives, but their cost is significantly higher...
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