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  1. johnnymist2003

    15MO3 PLATE MATERIAL

    Hi all, I am trying to find elevated yield and tensile strength properties for 15MO3 plate, for use in a PD 5500 vessel design. PD 5500 does not have stress values above 400 degC, my design temperature is 440 deg C. Thanks. John
  2. johnnymist2003

    Zinc and 300 series combination

    Hi all, I'm not a corrosion engineer, so forgive me if the terminology I use is incorrect. I have a 304 stainless steel stud bar passing through a hole in a galvanised carbon steel plate. I have been advised that to mix 304 ss and galvanised materials is not recommended as the zinc interacts...
  3. johnnymist2003

    Air test instead of hydrotest

    Hi all, for R&R, normally the vessels are refractory lined.You do not want to test using water as it will damage the refractory lining.In this instance, pneumatic test should be specified.Be aware that during the pneumetic test the stored energy due to the compressability of the air used for...
  4. johnnymist2003

    What is the main difference

    sk, it has to do with the process that is going on inside the vessel.Absorption and adsorption are two completely different mechanisms.I'm not a chemical engineer, so I can't explain the processes to you, but I do know that the vessels will be completely different in their internal structures...
  5. johnnymist2003

    O-lets in ASME VIII wall thickness calculation!

    Hi gbratis, 1) No, ASME does not exempt reinforcement calculations for o-let nozzles, except if they fall into the exemption categories as specified in UG-36 (c)(3). 2) In my experience, the weldoflanges, etc. are normally forged. Did you use the allowable stress values for the forging material...
  6. johnnymist2003

    vessel nozzle loading

    Hi, this issue of including pressure thrust on nozzles for WRC-107/297 analyses...If one takes a blanked manway nozzle, is it necessary to do WRC-107/297 nozzle load calculations?Certainly there is a pressure thrust on the blanked nozzle.This pressure thrust would create a substantial radial...
  7. johnnymist2003

    SA 234 WPB Pipe caps

    Hi all, PEHasan, I'd suggest that you approach your weld cap supplier for some dimensions of the weld caps.UG-32 design for 2:1 semi-ellipsoidal heads require the head shape to be truly ellipsoidal, or if manufactured using two radii then the crown radius must be 0.9D and knuckle 0.17D.Most...
  8. johnnymist2003

    BS 3059/5

    Hi Andy, thanks for the post. We actually managed to track down a copy of BS 3059/5:1958.The spec is : BS 3059/5 : Hot Finished Seamless Carbon Steel Boiler and Superheater Tubes.In the document the tensile strength is set at 27 tons/in^2 as a minimum, with a 35 ton/in^2 maximum.So, I have a...
  9. johnnymist2003

    BS 3059/5

    Hi all, I'm trying to find some mechanical and chemical properties for BS 3059/5 material (circa 1965).The material has since been replaced by an updated material specification, this much I know.The 1965 edition of BS 1515 I have does not list any modern equivalents, and the issues of BS 3059...
  10. johnnymist2003

    BS 1501-161 Gr.C

    Hi All, we are doing some retrofitting to a vessel manufactured from BS 1501-161 Gr.C material (1959). I think that this material is equivalent in terms of tensile and yield strength to BS 1501-161-430, however, I can't find any literature to confirm this. Can anyone confirm that I may use BS...
  11. johnnymist2003

    Stress Relief Vs. PWHT

    Hi all, we've all come across these confusing terms. At the company I worked at, we used the term "post forming heat treatment" and "post weld heat treatment". We used these because post forming heat treatment could be a stress relieve, or normalising (eg. on a dished end). We would then use...
  12. johnnymist2003

    HIC, SSC, SCC, HCL and HTHA

    Hi, first off, I am not a corrosion, nor materials engineer, but a vessel one.So forgive me if this post is useless. We are busy installing an air cooler with the following charcteristics. Design pressure 5590 kPag Design temperature 160 degC Wet sour service- H2 partial pressure 3730 kPaA H2S...
  13. johnnymist2003

    Reinforcement neer a Flat Head

    Hi Neil, sorry for the delay in the response to your question. Bear in mind that the shell is seeing circumferential stresses due to pressure (see UG-37, definition of tr), whereas the flat head is seeing bending stresses. I believe that it is the intent of the code that one should not "mix"...
  14. johnnymist2003

    PD 5500 clause 3.6.3.3.3

    Hi all, in PD 5500, cl 3.6.3.3.3(c) is stated: "Using a suitable stress analysis technique,....due to pressure p". What is a "suitable stress analysis technique"? Also, is there any way to reinforce / calculate the junction at the small end of the cone to avoid the 3.6.3.3.3 calculation? Ta. John
  15. johnnymist2003

    Reinforcement neer a Flat Head

    Hi, I assume that the flat head and cylinder are of the same material, and that the circumferential weld is near the flat head knuckle...Caluculate the maximum distance from the nozzle centreline to the start of the flat head knuckle (ie. the cylindrical portion). For area A1, take the...
  16. johnnymist2003

    Brinell Hardness

    Hi, if the tank is in HIC service, you could look at NACE MR 0175 or 0103 for guidance, though these are mainly for pressure retaining equipment (eg. vessels).I'm not a metallurgist, but hardness can be directly related to tensile strength, the higher the hardness, the higher the tensile...
  17. johnnymist2003

    UHX 13.5.9 and tube buckling

    Hi, These problems arise due to the different thermal expansions of the S/S and C/S, and the thermal expansion is dependant on the mean metal temperatures of the shell and tube sides of the exchanger. Have you confirmed that the mean metal temperatures are accurate (your process guys should be...
  18. johnnymist2003

    HEAT EXCHANGER DIMENSIONS

    Hi Picasa, designation should be "x"-"y" where x=shell inside diameter and y=tube straight length (for u-tubes up to the the bend tan line). John
  19. johnnymist2003

    U-TUBE TUBESHEET

    Picasa, refer to RCB-7.13 "The required effective tubesheet thickness for any type of heat exchanger shall be determined from the following paragraphs, for both tube side and shell side conditions, corroded or uncorroded, using whichever thickness is greater".In other words, one must check for...
  20. johnnymist2003

    SPLIT KEY RING IN FLOATING HEAD ASSEMBLY

    Picasa, I'll try to explain this as best I can, please reply with questions if you need clarity.The floating tubesheet is captured between the backing ring and the floating head flange. The outside diameter of the backing ring and the floating head flange is normally greater than the inside...
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