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Recent content by TomEun

  1. TomEun

    Galvanic Corrosion due to dissimilar Flange Joint in hydrocarbon service

    In addition to the good answers above, you may also need two-step assessment below. 1. Does this circuit require galvanic corrosion prevention? (Need to check fluid conductivity and dissolved oxygen-present and future) Please use Galvanic Potential Table/Curve under similar service condition...
  2. TomEun

    Degradation Mechanisms affecting Petrochemical and Chemical Industry

    The mechanism of Material Degradation is not simple because there are many issues from Mechanical (cyclic service, vibration, friction, overload), Process (upset conditions, wrong operation), Corrosion & Erosion design (with material selection)/prevention/monitoring/cleaning/fatigue corrosion...
  3. TomEun

    Interpretation of results - Charpy test

    All mechanical tests are subject to the following two categories. (i) Applicable standard test procedure (e.g., CVN Impact test: materials, heat treatment of base metal, test methods, test temperature, specimens-numbers/ directions/ locations/ machining/ subsize per base metal/PWHT/welding...
  4. TomEun

    Correct material for heating coil

    I believe you had already reviewed all candidate materials. Once you have selected a bare CS instead of ASS, DSS or Ti Alloys which are the most common materials in swimming pools, you may have to consider the followings continuously for the 10 years design life. - Corrosion Allowance: to be...
  5. TomEun

    Refinery Corrosion Textbook

    All references above are very useful to understand the qualitative data of materials and corrosion in refinery and petrochemical plants. API RP571, 3rd edition (March 2020) is the latest, however the contents are not remarkably changed compared to the 2nd edition. So, the 2nd edition is still...
  6. TomEun

    carbamate corrosion at moderate T & p?

    Here is a simple review for MOC in Urea plant. Several Urea licensors (Stamicarbon, Saipem, KBR, Uhde, Urea Casale, etc.) are often using specific materials (i.e., Safurex®, ASME Code Case 2295-2-UNS S32906, Alloy 2RE69, X2CrNiMoN 25 22 2 or Type 310MoLN) instead of conventional material (316L...
  7. TomEun

    Lean Amine - maximum recommended Chloride concentration to avoid ClSCC on heat exchanger tubes

    The threshold chloride content against pitting or SCC for stainless steels in amine solutions is higher than that in neutral seawater or acidic environment because the pH values in amine solution is normally 8.5 to 10.5 except the OVHD or reboiler of amine regenerator. 304L SS (chloride< 1000...
  8. TomEun

    UNS S17400 Material for Valve Stem

    NACE/ISO TG 299 committee (for MR0175/ISO15156) will continuously update the restriction on use of UNS S17400 for the next version because the premature failure of this material has been frequently reported. You may have to confirm whether the 17 bar (1700 kPa) is for system pressure or H2S...
  9. TomEun

    Mill tolerance for A672 Pipes

    You may have good answers from metengr and EdStainless. Here are some more information. In general, the thickness control of seamless pipes is more difficult than that of welded pipes (fabricated from plate materials). Therefore seamless pipes require more tolerance. Here is a general...
  10. TomEun

    Selection of Plate material

    You may have to consider the following three points (other than material cost). Basically the temperature condition should be clearly confirmed. 1. Graphitization If the 427C is based on the nommal operating condition, the material should be upgraded to Cr-Mo steel (e.g., 1-1.25Cr-0.5Mo steel)...
  11. TomEun

    TUBE &amp; PIPE DEFINITION

    As mentioned above, the most importance is the purpose. Pipe : mass transfer(The size can be larger to sustain the effective mass transfer.) Tube : heat transfer(The size should be smaller to sustain the effective heat transfer.) For instance, fired heater tubes (e..g, API 530/560) are...
  12. TomEun

    Is there standard comparable to MR0103 (Refining) that applies to Chemical Plants?

    Here is a general guide for wet H2S service (SSC). NACE MR0103 is for refinery processes which have wet H2S in the hydrocarbon. However the sulfide stress corrosion (SSC) can be occurred in other services including H2S and condensed water in the solution if the wet H2S corrosion reaction is...
  13. TomEun

    Elliptical head

    You may have to consider the following two cases. 1. Mechanical design (strength calculation) : If it is applicable to ASME Sec.VIII (or any other pressure vessel code), the required thickness of shell section (including the weld joint of 2:1 ellip. head to shell) shall be strength-calculated...
  14. TomEun

    PWHT cycles for C.S. test coupon

    No extra holding time for the future PWHTs of A516-70N is required because any precipitations (like Cr-Mo steels) of A516-70N (killed steel) and/or grain growth are not expected due to multiple PWHTs (under the low critical phase transformation temperature, around 715C for A516-70 and sound...
  15. TomEun

    Cryogenic &amp; High Pressure

    One of the reasons to select 321 SS instead of 304 SS is due to the different maximum working pressure (MWP) at elevated temperature (321 SS is higher than 304 SS). Please compare the MWPs for two metals in ASME B16.5. Thomas Eun

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