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Up Topic Welding Industry / Inspection & Qualification / use of structural bridge tacks on A106 pipe
- - By Flash Date 02-07-2008 09:10
Hi All

I have a question for you all that undertake inspections, particularly on pipe spools using tig
what is your opinion (or code interpretation from B31.3) on pipefitters using 5mm or 6mm structural grade round bar to tack spools together, eg. put the round bar in the prep and tack each side (some pipefitters call them bullets or bridge tacks), then the welders cut them out during the welding operation

is this preferrable to root tacks to the qualified procedure

what is the basis or justification for your decision

R
Flash
www.technoweld.com.au
Parent - - By chall (***) Date 02-07-2008 13:40
If the material is allowed by B31.3 than I would not have a problem with it.  If the material specification and grade is unknown, I would not allow the practice.

Charles
Parent - - By Joey (***) Date 02-07-2008 14:26
shouldn't be a problem for carbon steel materials (A36 / A106) as long as you will remove it during welding.

but be carefull, those welder paid per meter will use it as slugging to speed their work, specially for those weld joints not required RT/UT.

Regards
Joey
Parent - By js55 (*****) Date 02-07-2008 15:07
Bridge tacks like that are very common. Especially in B31.3 where GMAW-S roots are performed and in B31.1 where you prefer not to have your fitters break down J lips, or where you have heavy walls where processes other than GTAW can be used to increase productivity at the fit stage by higher deposition rates.
Parent - - By Flash Date 02-07-2008 20:13
HI Joey
this was my greatest fear, they make such nice filler metal to some operators
R
Flash
www.technoweld.com.au
Parent - - By Flash Date 02-07-2008 20:15
PS thanks for the feedback
Flash
Parent - By Shane Feder (****) Date 02-08-2008 08:23
Hi Flash,
We did many thousands of welds with "bullets" on the LNG trains in Karratha, carbon, stainless and ITCS with no problems. The pipefitter had to take his isometric drawing (with WPS noted on it) to the store and they signed out the correct round bar. The unused portion was signed back in at end of shift or end of pipe-setup, whichever came first. Every butt had to be visually inspected before the pipewelder left the area so it was quite easy to count the bullets removed from the butt on completion.
Admittedly, most of the work was 100% RT but even on the 5% and 20% lines it would be a very brave (or very stupid) welder who would weld over a bullet if he didn't know whether it was going to be bombed or not.
Regards,
Shane
Parent - - By Joey (***) Date 02-08-2008 17:14
Flash,

Alternatively, you may request for consumable insert ring for making critical welds, they are placed in the root of the weld joint when the joint is tacked up. The rings are available in different sizes and different analysis to match the pipe composition and size (class 1 to 5). We used GTAW to fuse the ring into the root of the joint for C/S materials. 

Regards
Joey
Parent - - By Flash Date 02-09-2008 01:58
Thanks again for the input guys
Shane, what you described seems a lot of extra control to ensure the right material went in the right place

Shane how did you go with the follow up for IIW / WTIA Inspection quals
R
Flash
www.technoweld.com.au
Parent - - By Shane Feder (****) Date 02-09-2008 04:30
Hi Flash,
Still working up in the Philippines so haven't had a chance to look into it.
Once I finish here I will be back to New Caledonia for 6 months or so, will have to look into it when I get back to Oz,
Regards,
Shane
Parent - - By CWI555 (*****) Date 02-09-2008 04:44
Need to hook me up on that philippine work shane.

Regards,
Gerald
Parent - By Shane Feder (****) Date 02-09-2008 09:09
It's a hard life Gerald but someone has to do it. LOL !!!
Up Topic Welding Industry / Inspection & Qualification / use of structural bridge tacks on A106 pipe

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