Square groove butt weld. full pen ?

By briandbenton Date 09-17-2013 11:28

I have a box truss in the shop with all square groove welds noted on drawings. a square groove butt joint with no dimensions needs no edge preparation and is usually in thinner materials, right? I have had inspectors tell me that if no details are given with the symbol then that denotes full pen. I did not think that applied to square groove butt joints with no prep. I thought that applied to an empty line and <CJP in the tail. Anyway, my main concern is that these box trusses are made of 1/4 and 1/2 angle. We are building them for another shop and they are telling me that all welds have to be U.T`ed. In my experience beveling or backgouging will have to be done to pass U.T. especially with 1/2 inch angle. My owner asked me about the symbols and we bid them with no edge prep, and no notes on U.T. on drawings. The drawings had several errors on them and we are waiting on conformation of several questions. (splice plates on angles instead of coping the support angle) Can anyone clarify If the simple square groove butt symbol has to be prepaired for a full pen(when no dimensions are given).http://www.aws.org/mwf/epx.png

By jwright650 (*****)

Date 09-17-2013 11:45

At a minimum the detailer should have put a root opening dimension on the welding symbol when specifying a square groove. This gives the welder/fitter some guidance to make sure the root is wide enough for access to the bottom of the groove. Is this work being done to a welding code? Reason that I ask is AWS D1.1:2010 shows (for pre-qualified welding procedures) a 3/8" Max basemetal thickness for GMAW and FCAW welding processes(1/4" max for SMAW)...this is with backing.(B-L1a) For a square groove without backing(B-L1b), this joint does require back gouging to achieve full pentration. You can weld up to 5/8" base material using Submerged Arc(SAW).
Details on these joints are in Fig 3.4 if using AWS D1.1.

By briandbenton Date 09-17-2013 12:13

Thank you for the response. Yes this is to D1.1 standards. The whole 9 yards; american mtrl. and consumables, inspection from D1.1-6.7 ect. The box trusses are columns for an electrical substation. I saw the max 3/8 max in code book, but was told if no dim. were given it implied full pen.(to prepare accordingly) I was going to argue, but i am going up against an outside inspector with 30 + years experience and wanted to get my facts straight. Welding is FCAW, but I will ask for a WPS from the other shop on how they want it done. They are supplying material and NDT. So if no root opening is shown, and no backing on 1/2 inch, that is not a pre-qualified procedure. With no root opening, backgouging is required, correct?(B-L1s)(B-L1b-GF) Even for 3/8, and what about 1/4? Thank you again for the help!

By jwright650 (*****)

Date 09-17-2013 12:16

Yes, backgouging is required even on 1/4". So you are splicing a piece of angle? Are you planning to weld the inside profile, flip over and grind the outside (or gouge) back to the weld that you placed on the inside?

By briandbenton Date 09-17-2013 12:27

Yes the print shows splice plates where they terminated support angles at the toe of the main corner angles. These welds would be in the vertical or horizontal position unless flipped on end.(38' high) If they show full pen, I will be back gouging/grinding, but with the basic symbol they gave me,(just the double square groove) I did not plan it into the job.

By jwright650 (*****)

Date 09-17-2013 13:26

>I will be back gouging/grinding, but with the basic symbol they gave me,(snip) I did not plan it into the job.

LOL...been there, done that, bought the T-shirt

By briandbenton Date 09-17-2013 14:05

They are coming to check my progress! Ha! Hope they bring new Drawings so my boss can discuss the new bid with their boss. Situation Normal!
Thanks again for the Info and helphttp://www.aws.org/mwf/epx.png

By 803056

Date 09-17-2013 14:29 Edited 09-17-2013 14:33

This is a cut from AWS A2.4. As indicated by the sketch, a symbol with no dimensions is a CJP.

D1.1:2010, Clause 2.3.5.3 second paragraph states the weld indicated by a welding symbol without dimensions or CJP in the tail must develop the strength of the adjacent base metal in tension and shear.

In the absence of a weld size listed by the welding symbol, it is prudent to make the weld CJP. The absence of a weld size ds not grant the welder or the contractor to do as they please.

When in doubt, direct a question to the Engineer for clarification. Everyone knows the consequences of the word "assume."

Al

NoDepthNoSizeSpecified17-Sept-2013.jpg (38k)

By jwright650 (*****)

Date 09-17-2013 14:44

Al brings up a good point about the lack of a depth of bevel, (only for a prepared groove) or weld size shown in the welding symbol...although it doesn't help your current situation, it is something to file away for future reference.

By briandbenton Date 09-17-2013 16:13 Edited 09-17-2013 16:15

Thank you for the clarification. Looks like they are going to the engineers on several points including the welds. The truss is poorly designed (support angles terminating at the toe of main angles without a cope to tie into the other leg of the main angle on most of the connections) Seems to me that everything should tie in together. But i'm just a supervisor with a little bit of inspection background. The references help alot, I look everything up when i can figure out how to find it. On the figure from my print it doesnt show a bevel groove>< only square groove []. Same difference?
Thanks again to All!

By briandbenton Date 09-17-2013 16:49

OK. If they give me the square groove butt weld symbol on 1/2 inch angle ( too big for prequal wps) with no root opening. Is that an incorrect drawing, or do i just need to know that backgouging will be needed? Do they only give that symbol when thinner materials are joined, and the penetration of the weld will be sufficient. (no edge prep needed in square groove weld) Or should they show another groove weld, and or root gap that would be sufficient for 1/2 inch? Especially if all 125 angles on this box truss will be U.T.'ed?

By 803056

Date 09-17-2013 19:19 Edited 09-17-2013 19:27

Brian;

Is the drawing a structural drawing, i.e., not a fabrication drawing, by chance?

Contract drawings do not need to be completely detailed. It is left to the fabricator to add the missing details to produce the required weld. The Engineer can simply show the location of the weld, leaving out details such as the type of groove, groove angle, root opening etc. The level of detail can be as simple as a reference line with the leader and arrow.

The absence of details gives the fabricator the opportunity to detail the joint using the groove details that optimizes the equipment they have available.

Grooved joints that do not indicate the weld is partial joint penetration are by default required to match the strength of the adjoining members in shear and tensile when D1.1 is the governing document. For all practical purposes, they are complete joint penetration. I don't know that the same requirements regarding strength is true for a joint that is fillet welded.

Best regards - Al