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[MW:31500] Re: ASME BPV Sec VIII div1 , UCS-68(b) - PWHT requirements

By Materials & Welding
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" 

On Saturday, 19 September 2020 at 09:01:21 UTC+5:30 MW wrote:
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)  

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