Hi there.. I am confused with the definitions of "backing" in ASME Section IX and AWS D1.1.
As far as I can understand of AWS D1.1, a single vee joint with backgouging is not considered "with backing." Here's what I understand from the code:
Though 4.12.1 has put CJP with backgouging together with CJP with backing in the same paragraph, but if follow the detail shown in Fig. 4.25 (A), it's under CJP "without backing."
But for ASME Section IX, there is no clear indication or clarification from the code that whether a single vee joint with backgouging is consider "with backing" or "without backing."
Here are the definitions of "Backgouging" and "Backing" from ASME Section IX:
"backgouging--the removal of weld metal and base metal
from the weld root side of a welded joint to facilitate
complete fusion and complete joint penetration upon subsequent
welding from that side"
"backing -- a material placed at the root of a weld joint
for the purpose of supporting molten weld metal so as
to facilitate complete joint penetration. The material may
or may not fuse into the joint."
From what I understand from these definitions, only after backgouging then back weld is considered "with backing." Before that it's welding without backing. So, is this single vee joint considered "with backing" or "without backing" if the joint would to backgouging and back weld???
Any response is greatly appreciated. Thank you.
-Alex-
Alex, I agree with your confusion. I've been doing ASME IX WPS' for a long time and using the term "without backing" when back-gouging and rewelding the root however recently my Authorized Inspector made me change my terminology to with backing, so that's what I now place with a clarifier saying what was done.
Thank you for your response. I have been asking alot of ppl about this, including AI and AIS. They are all saying the same thing that even though the welder may initially weld without backing on one side then backgouge and back weld, it's still considered a welding with backing. Because the welder doesn't have to worry about how good is the root of the welding, so no matter what, the root will still be backgouged then back weld. Therefore, it's considered a welding with backing.
In the welder qualification and WPS backing variable, QW402.4, it states that double-welded groove welds are considered welding with backing. Often, for clarification on AWS documents, insted of check boxes for "with backing" and "without backing", I have 3 boxes similar to below, then there is no debate at least as to what the procedure is calling for.
Required (welded from one side) None (welded from both sides) None (welded from one side)
Thank you for your response also. Regarding to your reply, If it's a double-welded groove weld then yes, It's definitely considered a welding with backing. But i was confused about a Single Vee joint not a double-welded groove weld, plus the ASME and AWS codes did not clarify whether the backgouging is considered with backing or without backing.
Regardless of the orignal joint configuration, single or double Vee, U, J, etc. If it is back-gouged and re-welded it is a double-welded joint.
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