Soaking time of production welds according to QW 407.2

[Fernandiux]

Gentlemen,
Our welding engineer is trying to increase the PWHT soaking time on production welds by 1.8 because some Inspector´s request.
Now a 3in. weld shall be PWHT at 1100 °F for 2.25 x 1.8 = 4.05 hrs instead of 2.25 hrs. per UCS-56-1.
From what I can read on the book and this forum that 80% of aggregate times at temperature is for test procedure qualification and not for production welds.

Any comment will be welcome.

Best regards,

 

[SectionIX]

PWHT time and temperature apply equally for PQR qualification and production welding. With respect to the 80% aggregate times at temperature reference from ASME IX, QW 407.2, most test coupons receive a PWHT in accordance with ASME Section VIII, Division I UCS-56 to insure mechanical properties are acceptable for destructive testing.

With the belief that you were referencing ASME Section VIII, Division I, Table UCS-56-1 (P 1 materials), there is nothing to prohibit additional soak time. You didn't mention the welding process, but in general, a change in the post weld heat treatment temperature and time range (ASME IX, QW 407.2) is a supplemental essential variable that would require the WPS be re-qualified to this new soak time if impact testing is required.

Is it possible your Welding Engineer is looking to perform the PWHT at a lower temperature for a longer time?



Excerpt from ASME Section VIII, Division I, UCD 56 (b)

(b) Except where prohibited in Tables UCS-56-1
through UCS-56-11, holding temperatures and/or holding
times in excess of the minimum values given in Tables
UCS-56-1 through UCS-56-11 may be used. Intermediate
postweld heat treatments need not conform to the requirements
of Tables UCS-56-1 through UCS-56-11. The
holding time at temperature as specified in Tables
UCS-56-1 through UCS-56-11 need not be continuous. It
may be an accumulation of time of multiple postweld heat
treatment cycles.

 

[DekDee]

Section IX,
My interpretation of OP is it is same temp but extended soak time.

Fernandiux,
Where is the inspector getting the 1.8 figure from ?
What was time and temperature of your PQR coupon ?
Cheers,
DD

 

[Fernandiux]

Thank you Gentlemen,
The extended soaking time is coming from the Inspector´s interpretation of QW 407.2, the test coupon for PQR was 1 ½” thickness and PWHT at 1260 °F for 2.5 hours. No impact test is required and the welding process is SAW.

Regards,

 

[DVWE]

If there is no impact testing required, QW-407.2 does not apply as mentioned above. See also QW-254

 

[Fernandiux]

From what I read on your posts, the welding engineer shouldn't extend soaking time on Production welds, Time and Temperature shall comply with ASME section VIII UCS 56-1 and PQR.

Any though?

Best regards,

 

[bpv66]

Something doesn't seem to add up. Why would the PQR be heat treated at 1260F if it were P1 material (P1 = 1100F minimum)? Also, I find it unlikely that a 3" thick production weld of P1 material doesn't require impact testing. MDMT of 3" thick Curve D material is around 10F (SA-516-70, normalized). It would be nice to have some additional information.

With all of that being said, the bottom line is that QW-407.2 does not apply if production impact testing is not required.

 

[Duwe6]

Sounds like a Sect IX misinterpretation. IX has nothing to do with the PWHT requirements of production welds. You are required to use the Design Code rules, typically Sect I or VIII. Excess 'soak time' is excess -- a waste of time and money. [might want to ask your Welding Engineer if the Inspector is planning to pay for the excess work]. Any ASME minimum soak time is ALREADY conservative, and somewhat excessive [by design]. Adding to that is silly.

 

[weldstan]

The Section IX requirement applies to the maximum time at temperature, not the minimum time at temperature as required by ASME VIII for production welds when impact testing is required.