Process Essential Variable

By - Date 07-01-2000 01:40

Per AWS D1.1, a PQR is qualified for T-, Y-, K- joints with open root / full penetration. A dual process is utilized with SMAW (E8010-G for the root bead and hot pass) and FCAW-G (dual shield) E81T1-Ni1 is used to complete the fill and cap. A WPS is written using these processes.
Is it permissable to omit the SMAW process and utilize FCAW-G only to complete the entire weld.
I've reviewed 4.7 and Table 4.5 and in D1.1 98 Edition and do not read were it specifically outlaws the omition.

By JFALK

Date 07-03-2000 03:59

1. Unless I have read your post incorrectly...there is no pre-qualified open root procedure according to AWS D 1.1.

2.Any change in the essential varible will require a new PQR. A change or deletion of a process is considered an essential varible change.

Not good news but this is what I believe to be correct. At home...don't have "the book" here. Will be happy to assist later this week.

By - Date 07-05-2000 17:47

Thanks for the reply!

1. This applies to a PQR that was run on Norsec 360 tube steel 16" and API-2H Plate. It was qualified by performing the requirements of D1.1 Section IV, Figures 4.27 & 4.28.
The reason this procedure had to be qualified was that the Norsec 360 is unlisted per D1.1. Otherwise, a WPS could have been written from the "prequalified requirements" per 4.12.4 & 3.13.4. Note that the figures and tables make reference to "root opening".
From my review of these sections, I conclude that AWS has provided prequalified parameters for one to write an open root WPS.

2. The PQR and welder qualifications included both of the aforementioned processes. The only essential variable I find that applies in this case is "the omission of backing for FCAW" per Tables 4.5 (35) and 4.10 (7). The initial passes with E8010-G (SMAW) provide backing for the FCAW.
Can you tell me were the code specifies that a change or deletion of a process is an essential variable?
I'm dealing with some hard-headed individuals that insist on black and white verification.

Please review these sections and let me know what you think.

Thanks, JK

By JFALK

Date 07-05-2000 19:44

!! There never seems to be black and white when dealing with AWS D1.1!!
Since you have outlined the situation and people that you are dealing with...have you pre-qualifyed the joint by RT or UT? Compared to the "labor" of sorting this problem out this would give substantial data to support the process development and cost is very reasonable!!
This would be very "black and white". No pun intended!

I did not read your post well. My review of "prequalified" open root was based on 3.13.3 (2) and I missed T, K and Y.

I still believe, however, based on table 4.5 that a deletion of a process from the WPS would require requalification. Table 4.5 applies essential varibles to singular process welds. This instance would , in essence change items 1,2,3 of 3.6.

Hope I have helped. D1.1 is complex and I network with others often.