PWHT Maximum Material Thickness ASME VIII-1
PWHT Maximum Material Thickness ASME VIII-1
(OP)
Am I correct to make the assumption that the intent of UCS-56(d)(1) through (5) term "maximum material thickness"is intended to reference the "governing material thickness" as defined in UW-40(f)(1) through (6)?
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RE: PWHT Maximum Material Thickness ASME VIII-1
RE: PWHT Maximum Material Thickness ASME VIII-1
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RE: PWHT Maximum Material Thickness ASME VIII-1
Keep in mind that the PWHT requirements and terminology referenced in Subsection C, Part UCS-56 applies only to CS and low alloy materials, whereas, the information in Subsection B Part PW applies to any fusion welded construction, if applicable, and so local PWHT or furnace PWHT may be performed, and different terminology is used.
RE: PWHT Maximum Material Thickness ASME VIII-1
Other Subsection C material classes (Paragraphs and Tables) UHT-56, UNF-56, and UHA-32 use the "nominal thickness" term which I believe is appropriate.
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RE: PWHT Maximum Material Thickness ASME VIII-1
Thickness in UCS-56(d)(1) through (5) is the maximum head and shell plate thickness, which is different from the weld thickness defined in UW-40(f). UCS-56(d) is used to control thermal gradient during heating and cooling. UW-40(f) is for weld depth used to determin if a weld is to be heat treated.
For example, if a 2" thick shell can welded to a 1 1/2" thick shell can. You use 1 1/2" per UW-40(f) to decide PWHT is required; you will use 2" to calculate heating and cooling rate per UCS-56(d).
RE: PWHT Maximum Material Thickness ASME VIII-1
Interpretation: VIII-1-89-186
Subject: Section VIII, Division 1 (1989 Edition), Nominal Thickness Requirements to Comply with PWHT Procedures
Date Issued: April 3, 1990
File: BC90-305
Question: In using the attachment detail of Fig. UW-13.2 sketch (d) in Section VIII, Division 1, can the weld joint thickness of a shell to tubesheet attachment be considered the maximum metal thickness in determining the rate of heating and cooling for postweld heat treatment?
Reply: No. See UW-40(f)(5)(c).
So then, jamesl, is this interpretation wrong? or did the committee not answer the question?
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RE: PWHT Maximum Material Thickness ASME VIII-1
RE: PWHT Maximum Material Thickness ASME VIII-1
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RE: PWHT Maximum Material Thickness ASME VIII-1
Here is what UCS-56 (d) states before going into specific PWHT ramp requirements for controlling thickness of the shell, head, etc
The requirements in UCS-56 (d) 1-5 pertain to PWHT ramp rates based on what thickness is being exposed to PWHT. The maximum or controlling thickness could be nominal thickness as described in UW-40 or by the thickest portion of the shell undergoing PWHT.
RE: PWHT Maximum Material Thickness ASME VIII-1
Which edition of the code are you using? The wording in UCS-56(d) is now "the maximum metal thickness of the shell or head plate in inches", not "nominal thickness". If it is nominal thickness, I would agree that it refers to UW-40(f).
RE: PWHT Maximum Material Thickness ASME VIII-1
I think, as metengr has just explained, is that the maximum metal thickness is derived from UW-40(f) which considers the joint configuration as well as base material thickness and should be applied to entire vessel or part of a vessel being post weld heat treated in a furnace charge.
Can it be that significant? probably not, but, I think as you do, the terms should be consistent. Just in this thread alone, there is disagreement, who else needs clarification?
I think the term in UCS-56(d) paragraphs should be "nominal thickness" or at least "maximum nominal thickness" as defined in UW-40(f) for any item in a furnace charge.
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RE: PWHT Maximum Material Thickness ASME VIII-1
The code uses "the maximum metal thickness of the shell or head plate", not just "maximum metal thickness". Welds in nozzles thicker than shell or head plates will not be considered here. It is different from UW-40(f).
RE: PWHT Maximum Material Thickness ASME VIII-1
metengr says yes..you say no
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RE: PWHT Maximum Material Thickness ASME VIII-1
FAQ731-376: Eng-Tips.com Forum Policies A question properly stated is a question half solved.