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Recent content by dbsmith

  1. dbsmith

    Weld Mgmt Software

    Can anyone offer an opinion of the useability of the commercially available software for weld management? I'm planning on implementing weld management software this year. I work mainly with ASME Codes (Section I, VIII, IX, B31.1, B31.3) and NBIC. I do a limited amout of work with AWS D1.1 and...
  2. dbsmith

    Determining Valve Life

    Can anyone offer a rule of thumb to estimate the life cycle of steam valves? We are considering substituting A217 WC6 (1-1/4 Cr - 1/2 Mo) for A217 WC9 (2-1/4 Cr - 1/2 Mo) in a high pressure steam line in a combined cycle power plant, as a capital cost savings measure. I'm expecting that the WC6...
  3. dbsmith

    PMI Machine

    You need an optical emmission analyzer to read carbon values. One machine I am aware of that does this is Spectroport. You can find further info on their web site www.spectro-ai.com
  4. dbsmith

    Welding over thermal spray coating

    The vessel is not yet out of service. We are basing our assumption that the cracks extend only through the SS overlay based on previous UT and PT inspections. When the vessel is taken out of service during an upcoming shutdown, we can determine the exact extent of the repair needed, by chasing...
  5. dbsmith

    Welding over thermal spray coating

    Thanks for the insight. We are actually trying to avoid a weld repair to the base metal, and the subsequent PWHT cycle it would require. The application is on a high pressure chemical reactor ring joint flange. During extended service at 2200 psig @ 800 F, stress cracks have developed in the...
  6. dbsmith

    Welding over thermal spray coating

    Does anyone have experience welding over a thermal spray coating placed by HVOF (high-velocity oxy fuel) process? I need to do a weld metal build-up repair on 2-1/4 Chrome (SA387-F22) base metal that has been overlayed with 347 stainless. The weld metal build up will also be of 347 SS. I'm...
  7. dbsmith

    Stainless sensitisation

    Attack by polythionic acid is a consideration, and I believe the 321 was specified due to its resistence to SCC. The operating temperature will be 820 F, which is in the range that service related sensitization can occur. Since placing this post originally, I have obtained further information...
  8. dbsmith

    Stainless sensitisation

    The application is above ground piping carrying SO2 vapor. It is a relatively low pressure system, and not subject to cycling, so it is not likely to be affected by fatigue.
  9. dbsmith

    Stainless sensitisation

    Thank you both for the quick replies. I'll use this to try to help prevent the customer from throwing his money away.
  10. dbsmith

    Stainless sensitisation

    Can anyone explain the circumstances in which PWHT of 321 SS is appropriate? A customer has recently asked my shop to prepare a WPS for welding SA-312 TP321 pipe to itself and apply 1100 deg F PWHT for 1 hour. This seems like a recipie for carbide precipitation to me. The base metal thickness is...
  11. dbsmith

    P91 to SS Weld

    Thanks to all for the advice. The application is HRSG drains, and as bngreene noted, the weld is outside of the temperature range where P91 provides hi-temp strength and creep resistance. I'm not positive as to why 304L was specified - I suggested 304H, which usually takes PWHT better than L...
  12. dbsmith

    P91 to SS Weld

    Does anyone have experience joining SA335 Grade P91 to SA312 Type 304L stainless? In the absence of other advice, I plan to butter the P91 with ERNiCr3 filler metal and apply PWHT, then weld stainless to the buttered section again using ERNiCr3. Am I headed in the right direction? Thanks.
  13. dbsmith

    Completion of Partially Fabricated Vessel

    My shop is an ASME U Stamp holder. We have been asked to collect the components of a partially fabricated Section VIII vessel from a shop that has declared bankruptcy and complete the fabrication. The cylindrical shell sections are rolled and long-seam welded; the spun heads are welded to...
  14. dbsmith

    Hardness Testing in 1-1/4 Cr Piping

    Thanks for the info. I should have pointed out that the customer's requirement applies to any chrome alloy, and to carbon steel in "Aggressive Environmental Service" such as caustic.
  15. dbsmith

    Hardness Testing in 1-1/4 Cr Piping

    Thanks for the response. My premise is that the impression in the HAZ already indicates the effect that welding is having on the base metal. The material specification already provides a range for the base metal, so the test in the field is redundant.

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