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  1. Metalguy

    Austenite/Austenitization...

    How are the bearings failing? Ball, roller, needle, or what? "You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only...
  2. Metalguy

    316L gasket failure

    What kind and temp. of the water? Cl- level? Continuous or intermittent flow? "You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them...
  3. Metalguy

    Steel chemical Composition is 4340 or not??

    That looks like a somewhat unusual fatigue fracture. You need to find out how hard the shaft was supposed to be and how hard it is--from surface to core. You have a pretty "lean" heat of steel compared with real 4140, and it probably wouldn't harden if quenched in the usual oil/polymer. It...
  4. Metalguy

    Steel chemical Composition is 4340 or not??

    Can you post good pictures of the fracture surfaces? What diameter is the shaft? Required and actual hardness? "You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send...
  5. Metalguy

    Update - Name that corrosion

    Where's the photo? Monel resists reducing conditions, while the stainless steels resist oxidizing. "You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals...
  6. Metalguy

    Cracking of 5120H material output shafts (automotive) during straightening operation

    The core hardness isn't the problem. You could try raising the tempering temp. a bit to get a slight reduction in surface hardness. If that doesn't help. I'd be tempted to look into a "micro" shot peening effort. The idea would be to use fine shot size, and only peen in the minor dia. areas...
  7. Metalguy

    Cracking of 5120H material output shafts (automotive) during straightening operation

    Is it possible to straighten after tempering? I think straightening before is asking for cracks. How much movement are you correcting? A Rc61 surface won't take much movement at all. Have you correlated the cracking vs amount of straightening needed? "You see, wire telegraph is like a very...
  8. Metalguy

    How to safely contain a fall of heavy equipment?

    Cardboard honeycomb. "You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein
  9. Metalguy

    Under Ground Water Pipes Connectors

    How is the pipe itself protected? "You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat."...
  10. Metalguy

    Galling of Wear Rings on Centrifugal Pump

    Try Nitronic 60 or equiv., depending on your cl- level, etc. "You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only...
  11. Metalguy

    Main reason of PWHT by carbon steels.

    No on the first question. If you mean the likelihood of HAZ cracking w/o pre or post weld HT, then yes. "You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals...
  12. Metalguy

    Main reason of PWHT by carbon steels.

    CE isn't used to determine the max. hardness a steel can reach. It is a measure of hardenability, which means how deep/thick that steel is capable of being hardened. It is related to the time a steel takes for austenite to transform by diffusion to pearlite. The higher the CE, the less time...
  13. Metalguy

    Main reason of PWHT by carbon steels.

    "Carbon steel" has a wide range of compositions that apply to your questions. There's low, med and high C, along with lots of small amounts of elements that can affect hardenability. Even the allowable variations of some elements in low alloy steels can make a big difference. So yes, a PWHT...
  14. Metalguy

    Installation of 304L stainless steel pipe

    You have to get a lot of info about the water and flow conditions. Is the water in a closed loop? Is it treated? With what? Wet lagging with a lot of cl- will probably ruin that pipe at that temp. Hopefully whoever designed it knew what they were doing. "You see, wire telegraph is like a...
  15. Metalguy

    Installation of 304L stainless steel pipe

    Too many unknowns. What is flowing? Chloride content? Constant flow? Temp? Cl- of lagging? For now, do not let the initial fill water to stay stagnant in the pipe w/o lots of high-flowrate flushing. "You see, wire telegraph is like a very long cat. You pull his tail in New York and his...
  16. Metalguy

    A335-P22

    With the 2 1/4 % Cr and 1% Mo, P22 is a fairly deep hardening steel--far deeper than the same C level of a plain carbon steel. If it's flame/thermal cut cold, the surrounding metal will most probably pull heat away from the HAZ fast enough that martensite will form. You don't need to be...
  17. Metalguy

    A335-P22

    You'd run the risk of making untempered martensite next to the cut, which is quite brittle and crack-prone. It's possible the weld prep might not remove all such cracking, and possibly cause a rejected weld or worse if postwelding NDE doesn't find it. "You see, wire telegraph is like a very...
  18. Metalguy

    316SS piping for hydrogen gas service

    You are correct. If you want to passivate, you can pump a citric acid solution thru the installed piping--beside using the traditional nitric and nitric/HF mixes. The citric acid must be heated, but it's a lot safer than the others. "You see, wire telegraph is like a very long cat. You pull...
  19. Metalguy

    Case Hardening and Carbon Content

    I think you guess right. Tell the lab next time. "You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is...
  20. Metalguy

    316SS piping for hydrogen gas service

    Should be OK. Atomic H, usually generated by corrosion, will pass right thru both 316 and a passive layer, but you shouldn't have any. Your 316 will already have a very thin passive layer. 316 is better than 304 because the higher Ni makes the austenite more stable during any cold-working...

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