Welding Process

Date 04-04-2007 13:25

You could use combined WPS' if your contract or drawings allow it. If your WPS has GTAW for the root and say, SMAW for fills and cap, but you also have another WPS that covers SMAW root, fills, and cap, you could use that one. It all depends mainly on what your customer specs and drawings allow. Per ASME, combined WPS' are allowed, provided the essential variables for each WPS are followed. It would also depend on what your welder is qualified for.

By js55

Date 04-04-2007 14:41

Also, under ASME IX WPS's are backing irrelevent so SMAW could be used for the root if you have a PQR, but welder quals aren't. You may be able to do it procedure wise, but the welder may not be qualed for non backing with the F# he qualed with.

By Bill M

Date 04-04-2007 16:55

Just curious if the original GTAW WPS require a backing gas for the root pass?

By js55

Date 04-04-2007 17:05

If your essentially eliminating the GTAW WPS then you eliminate all variables associated with that process and WPS. Only the variables associated with the SMAW PQR/WPS would be applicable.

By Bill M

Date 04-04-2007 19:51

I understand that part, but my question is if the original procedure required a GTAW root with say an argon backing gas....would you allow the root to be welded with Stick 308L with no backing gas?

By new tito (***)

Date 04-04-2007 20:48

I would say that if you have a WPS for the 308 SMAW that does not require a backing gas, then yes, you would use it just like the WPS says...with 308 with no backing gas. I think that say, you have 2 procedures; 1) GTAW root and FCAW fill and cap; 2)SMAW (6010) root and (7018) fill and cap - you could use the SMAW 6010 for the root of a joint, just as it calls for in #2, and then use the FCAW for fills and cap in #1, as long as none of the essential variables are changed in either of the processes.

By Joseph P. Kane (****)

Date 04-04-2007 22:51

I may be missing the point here. You have a joint with a root pass "specified in the relevant ASME IX WPS as "GTAW"." . The approved WPS says GTAW?!?!?! How do you now justify changing the process at all?

By Shane Feder (****)

Date 04-05-2007 01:45

Turkmen,
If the welder has an SMAW welder qualification and all the essential variables are correct then it is acceptable providing you have a qualified WPS for SMAW root run.
If you have neither you are in a spot of bother,
Regards,
Shane

By CWI555

Date 04-05-2007 04:00

QW 200.4 (B) gives the specifics on this. Additional information can be found in QW 200.4 main paragraph.

Regards,
Gerald

By nosetackle (**)

Date 04-05-2007 05:27

my dear friend turkmen :)

According to your company's project specification all root passes should be done by GTAW,

sorry mate.

T,

By Turkmen TARI Date 04-05-2007 06:13 Edited 04-05-2007 06:19

I neither referred to a company nor to a project specification. I just asked if it is technically possible as per the Code and already got the answers.

Thanks for the replies.

Turkmen

By Lawrence (*****)

Date 04-05-2007 07:45

Turk

WPS = Project Specification

I hope you understand that the answer you got was a "No" you may not SMAW a root pass with your current paperwork.

The exception is that you may qualify another procedure by testing that includes an SMAW root. This exception assumes other contract languages do not forbid SMAW roots.

By js55

Date 04-05-2007 13:25

ASME does not segregate processes by pass, or variables by coupon. In other words, you run a coupon with say GTAW or SMAW. ASME does not distinguish variables that would prevent using the SMAW as a root pass. And backing gas is a non essential variable.
However, once again, this does not relieve the engineer from the responsibility of sound engineering judgment. In this case, being SS you would most likely have to add a metal backing such as a chill ring to support the SMAW process(backing also being anon essential variable). And there is also the issue of the HAZ to consider, and this is the critical point for SS. So therefore, as I would not recommend using the SMAW process for the root pass for this reason, there is nothing in ASME that prevents it.

By js55

Date 04-05-2007 13:41

I suppose I should add that were the alloy CS I would have no problem running SMAW as a root pass,(say if the PQR coupon was 1 1/2" with GTAW, SMAW and SAW and using 7018 with a chill ring, or for that matter even a ceramic backing with SAW), but SS presents a unique concern. And that is oxidation of the HAZ.