Code interpretation

[sayee1]

Scope:
1. AWS D1.1: 2000 Table 4.5 addresses the PQR essential variable changes requiring WPS re-qualification for SMAW, SAW, GMAW, FCAW, & GTAW. Clause 4.7.1 states that changes beyond the limitations of PQR essential variables shown in Table 4.5 shall require re-qualification of the WPS.
2. Table 4.5 S.No. 32 states that “a change in groove type (e.g., single-V to Double-V). Qualification of any CJP groove weld qualifies for any groove detail complying with the requirements of 3.12 or 3.13)” as an essential variable. Table 4.5 S.No. 33 states that “a change in type of groove to a square groove and vice versa” is an essential variable.
3. Table 4.5 S.No. 32 states that “For the PQR groove area, an increase or decrease >25% in the number of passes” is an essential variable. Note 6 mentions that “If the production weld groove area differs from that of the PQR groove area, it is permissible to change the number of PQR passes in proportion to the area without requiring re-qualification”.
Purpose of enquiry:
Interpretation of the code requirement for the following cases.
1. There are two PQRs, one qualified with SMAW for 6G position, on an 8in. sch.80 pipe (as per table 4.2), and another qualified with FCAW for 6G position, on an 8in. sch.80 pipe (as per table 4.2).
2. There are two PQRs, one qualified with SMAW for 6GR position, on a test joint (as per Figure 4.27), and another qualified with FCAW for 6G position, on a 6 in. sch.120 pipe (as per table 4.2).
3. A PQR has been qualified with SMAW process on an 8 in. Sch.80 pipe using a single- V CJP as per Figure 4.24. For e.g. let the PQR have a groove area of 75mm2 and 25 passes with SMAW process.
4. A PQR has been qualified with SMAW process on an 8 in. Sch.80 pipe using a single- V CJP as per Figure 4.24.



Proposed reply:
1. Can the two PQRs be combined to make a WPS with SMAW root and hot pass and the remaining welding with FCAW such that the essential variables for both the SMAW and FCAW processes as per table 4.5 are maintained.
2. Can the two PQRs be combined to make a WPS with SMAW root and hot pass and the remaining welding with FCAW for a T-,K- Y-production joint such that the essential variables for both the SMAW and FCAW processes as per table 4.5 are maintained.


3.
a. Can the PQR be used to make a WPS for welding a Production single- V CJP joint for an 8in. Sch 80 pipe with 75mm2 area such that the number of passes is 32 such that all the other essential variables for the SMAW process as per table 4.5 is maintained.?
b. Can the PQR be used to make a WPS for welding a Production double- V CJP joint for a 50 mm thickness pipe such that the number of passes is 545 for a 1310 mm2 weld groove area such that all the other essential variables for the SMAW process as per table 4.5 is maintained.?
c. Can the PQR be used to make a WPS for welding a Production double-V CJP joint for a 50 mm thickness pipe such that the number of passes is 560 for a 1310 mm2 weld groove area such that all the other essential variables for the SMAW process as per table 4.5 is maintained.?
d. Can the PQR be used to make a WPS for welding a Production double bevel CJP joint for a 50 mm thickness pipe such that the number of passes is 272 for a 655 mm2 weld groove area such that all the other essential variables for the SMAW process as per table 4.5 is maintained.?
4.
a. Can the PQR be used to make a WPS for a production fillet weld with a single pass of maximum 6mm such that all the other essential variables for the SMAW process as per table 4.5 is maintained.?
b. Can the PQR be used to make a WPS for a production fillet weld with multiple pass of 8mm and over such that all the other essential variables for the SMAW process as per table 4.5 is maintained.?


Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
email: sayee_prasad@yahoo.com
The black holes of nature are the most perfect macroscopic objects there are in the universe: the only elements in their construction are our concepts of space and time.

 

[pipewelder1999]

I'll take a stab at it,

1)Yes however your minimum diameter will be 8" per Table 4.2. If the Test pipes had been 6" sch 120 and 8" schedule 80 then the minimum diameters would have been 4"

2) Yes, provided the 6gr coupon was 6" diameter else the minimum diameter would be restricted. Fig 4.27 only lists a minimum diameter.

3) a) No. You could increase the number of passes by up to 25% for the PQR Groove area. 32 is an increase greater than 25%

b) In the test setup you had .33 passes per mm^2 . You could increase that by 25% per note 5 up to .412 Passes per mm^2. The increase you note above is .416 passes per mm^2 which is above the allowable increase of up to 25%. NO

c) Same as above. The increase is greater than 25%. NO
d) Same as above . The increase is greater than 25%. NO

4) I'm still studying this

Anyway, thats what I could discover. I hope that you will correct me or advise me of any of the areas whare I may be off. My math stopped in the 9th grade so I may have made an error regarding the cross sectional area but I think its correct.

Gerald Austin
Iuka, Mississippi

http://www.weldinginspectionsvcs.com

 

[pipewelder1999]

REVISION to my above post.


1) YES. I misread the diameters and thought 0ne was 6"

Gerald Austin
Iuka, Mississippi

http://www.weldinginspectionsvcs.com