Table 4.5 Essential Variable Confusion

Date 05-22-2012 01:10 Edited 05-22-2012 01:12

There are many old posts that discuss qualified weld procedure groove angle qualification range but most do not specifically address my situation.

My situation is:
I already possess a previously qualified D1.1 weld procedure.
Process is GMAW.
Material is ASTM A710.
Original PQR used a 3/4-inch plate, CJP V-groove butt weld with backing strip and 3/16 root opening, included angle of 75 degrees.

Our new production weld requires three type of welds:
1. simple fillets.
2. CJP double bevel TC-U5-GF welds, specifed bevel angles of 45 degrees.
3. CJP single bevel corner weld similar to TC-U4a-GF, specified bevel angle of 45 degrees (no backing bar but backed by a fillet on the opposite side).

My confusion comes from PQR Table 4.5 essential variable #31 which says my old PQR is good for any other CJP groove detail conforming to 3.13 (for which both new production welds will do so) BUT Table 4.5 essential variable #33 indicates that my original PQR bevel angle of 75 degrees far exceeds the permitted "as fit-up tolerance" of either TC-U5-GF or TC-U4a-GF which is only + 10 degrees/-5 degrees.

Please help to decide if essential variable #31 allows me to immediately go into production or does essential variable #33 force me to qualify two new procedures?

Thank you

By 803056

Date 05-22-2012 03:46

Hello Tom;

Is anyone watching your operation?

Get it done before someone catches you! If the inspector is bird dogging you, buy him a coffee and give the sports page and git it done while he's busy reading.

Let's get serious. You have a WPS that was qualified by testing. The PQR records the groove angle that is greater that what is typically used by a prequalified WPS, but wait, Table 4.5 says you are still qualified to weld and prequalified joint detail per clauses 3.12 and 3.13 which leads you to the joint details shown in figures 3.3 and 3.4. (Reference D1.1: 2010, Table 4.6, item 31)

Check your base metal. You listed ASTM A710, but you didn't list the grade. That may makes a difference in the range of base metals you can weld if you are not welding a prequalified base metal listed in Table 3.1 (in other words A710 Grade A class 1 or 3 as found in Table 4.9).

I may be missing something, but hey, the advice is worth every penny you paid.

Best regards - Al

By tom cooper (**)

Date 05-22-2012 11:05

Hi Al and thanks for your valued opinion.

The alloy used during the original PQR testing was A710 Class A grade 1, listed in Table 4.9, the same as will be used in the upcoming production.

If you think the original weld procedure configured with a wide 75 degree bevel ( needed at the time to address restricted accessibilty problems, or so I am told) is permitted for use on the 45 degree bevel groove joints, than what is the intent of Table 4.9 essential element #33, i.e., decrease in groove angle beyond the tolerance cited in clause 3.13 ??