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Up Topic Welding Industry / Technical Discussions / Backing rings and retainers
- - By dlmann (**) Date 04-24-2005 09:51
None of our WPS's permit retainers. My question is, are backing rings and retainers the same thing? If they are different what is the purpose of a retainer?
Regards, Donnie Mann
Parent - - By MBSims (****) Date 04-25-2005 01:37
I don't have the official AWS definition of "retainer" handy, but I would consider it to be removable, such as ceramic backing or a copper shoe.
Parent - - By GRoberts (***) Date 04-25-2005 18:38
Believe it or not, AWS A3.0 - Standard welding terms and definitions does not define the word "retainer".
ASME is about the only place I see it used. ASME has a definition in QW/QB-492, as a "nonconsumable material, metallic, or nonmetallic, which is used to contain or shape molten weld metal."
Parent - - By JM_VRCIC (*) Date 07-24-2009 15:12
Right, I search for it in ASME IX in QW-492 in it appears. My question is this: I have to do a WPS for a starting project, and I am hesitating about the PQR is qualified without a backing for the F3, but do I consider the F3 as a retainer for the F4 or a backing? As I got the definition in QW-492, backing is only for the root pass, am I right? And retainers are to shape... that's my doubt. Any ASME Inspector can help me with this?

Thanks, and you are welcome to send me PM.
Parent - - By pipewelder_1999 (****) Date 07-24-2009 15:38
In either case for most processes using ASME Sec IX as the only governing code, Backing is a non-essential variable. Thus a flat plate welded from both sides or an open root could qualify a WPS wps with or without backing. Retainers and backing have to be ADDRESSED.

Understand that "good Practice", Project specifications, or other referenced codes of construction may add to this requirement. Just because it is or is not required by a code does not mean it is GOOD or BAD to control or restrict further.

In direct reference to your situation, in cases where it IS restricted, qualification WITHOUT backing often times allows production of joints WITH backing.

As far as What the backing is made of (Backing Type). It can be referred to as "Weld Metal", or I think just "Required".  Backing does apply only to the root pass however I have seen it referred to on fillet welded tee joints which confuses me. I have even seen documents rejected by very knowledgable people for not addressing backing for fillets but that is another subject.

Have a nice day.

Gerald Austin
www.weldingdata.com
Parent - By pipewelder_1999 (****) Date 07-24-2009 15:44
X-86-54
Question (2):  Must the actual composition of the
backing material used in the qualification of a
WPS be documented on the PQR?

Reply (2):  No.
Parent - By JM_VRCIC (*) Date 07-24-2009 15:57
Thanks a lot Gerald.
Parent - - By Bonniweldor (**) Date 04-27-2005 11:58
A ceramic backing would be considered a retainer, and which is not indeded to mix with the weld metal, though, under a SAW weld pool, I think there is a slag-metal type interaction with the ceramic backing (alumina appears to be the primary constituent).
Parent - By 803056 (*****) Date 07-24-2009 15:36
It is a nonessential variable per ASME Section IX for those processes where they are applicable. You can add it or delete it with the stroke of a couple of keys on your keyboard after you check the applicable construction code.

Best regards - Al
Up Topic Welding Industry / Technical Discussions / Backing rings and retainers

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