ASME BPV Sec VIII div1 , UCS-68(b) - PWHT requirements

[Raghuram Bathula]

Can you please provide your interpretation for the following requirements of UCS-68(b)
Vessel MDMT - 48 °C , PWHT - not required

In accordance with para UCS-68(b) PWHT is required except for Category A and B joints with 100% RT, lightly loaded attachments and seal welds only.
and it is silent on category C , D welds and other attachments.

Question: does this mean PWHT is required for Category C and D, even though it is exempted for Category A and B welds? then vessel will undergo local PWHT
In my opinion we should not interpret this way and look for only what is code specifies (i.e. if Category A and B or other welds as specified is exempted entire vessel is exempted)  

[MW]

If a weld joint has a coincident ratio higher then 0,35 then the same need to be PWHT with the following exemptions from PWHT (even if coincident ratio is higher than 0.35):   

Category A and B joints which respect the condition indicated in UCS-68(b)(1) - e.g. 100%RT.

Lightly loaded attachments (<25% stress value) which respect the condition indicated in UCS-68(b)(2)(-a) 

Seal welds (tube to tube sheet)

 It does not exempt from PWHT the category “C” and “D” joints , and fillet welds (except as defined as “lightly loaded attachments” 

[govindan krishnamoorthy]

Since the Code is specifically indicated exemption only  for Category A and B joints. ( I checked for ASME INTREPRATION sheet not found any specific on this query).

Hence , this does not give provisions to take exemption credit for other categories which doesn't indicated in the code specifically. 

Plz provide if u have any latest interpretation if any for further discussion. 

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From: material...@googlegroups.com <material...@googlegroups.com> on behalf of MW <raghura...@gmail.com>
Sent: Wednesday, 23 September 2020, 11:06
To: Materials & Welding
Subject: [MW:31500] Re: ASME BPV Sec VIII div1 , UCS-68(b) - PWHT requirements

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[George Dilintas]

Yes C and D welds are not exempted. most probably because a geometrical discontinuity is always associated with a C and D weld.

There is also an interpretation relevant to UCS-68(b):

Standard Designation:	BPV Section VIII Div 1
	Edition/Addenda:
	Para./Fig./Table No:
	Subject Description:	Section VIII, Division 1 (1998 Edition, 1999 Addenda); UCS-68(b)
	Date Issued:	01/14/2000
	Record Number:	BC99-597
	Interpretation Number :	VIII-1-98-99
	Question(s) and Reply(ies):	Question: Do the requirements of UCS-68(b) in Section VIII, Division 1 apply to tube-to-tubesheet welds? Reply: Yes.

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Dr. Georgios Dilintas,

Dipl. Ing. In Aeronautic and Space Engineering

Ph.D in Mechanics of Solids - Computational Mechanics

A.I.S, A.N.I, IRCA Lead Auditor

Welding, Stress Analysis, Corrosion, QA/QC, Failure Analysis, Risk Analysis

[israr]

Dear Team,

I have done stress relieving of dish ends, Material P1 and kept temperature 590 degree to 600 degree, is it acceptable.

Pls. provide some reference, if not acceptable let me know if again we have to do the stress relieving.  

[Pravin Kurade]

Yes as per UCS 56 it is acceptable 

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