Large Diameter TKY joint with backgouging

Date 02-20-2013 19:26

6GR is the position of the joint. If this joint can be rolled or positioned in a manner where the welding can be done in a flat or horizontal position, then you may be able to wiggle out of the 6GR requirement. If the joint has to remain in position, then you may need that 6GR welder. The "R" is a restriction for the welder to work around during the welder qualification test on a 6G positioned joint and qualifies the welder for 6GR vs 6G. You can see these positions shown in Figure 4.4(D) and Figure 4.4(E).

By KDM Date 02-20-2013 20:04

Thanks for the speedy response jwright.
The main brace is flat, so its like a "K" on its back if you get me, I looked at the figures 4.4 D & E, but the configuration looks more like 2G and 3G to me.
Also my contractor is saying that tubes of the size we have can be treated as plate, is he pulling my chain?
I kinda want him to be right but I don't care too much as long as the weld is right and to code!

By jwright650 (*****)

Date 02-20-2013 20:13 Edited 02-20-2013 20:16

Maybe...is your pipe/tubing equal to or larger than 24" OD?[ EDIT* I see you said 7" dia in post#1] You can look at Table 4.10 for positions qualified depending on the test taken. But looking at the Table, it appears that only PJP TYK connection (not a CJP TYK) can be treated as plate (see Note c).

By welderbrent (*****)

Date 02-20-2013 20:19 Edited 02-20-2013 20:25

Along with John's great resonse you may want to look at Table 4.10 to see what they are qualified for after completing a particular test. Only the Pipe or Box tube 6GR test qualifies the welder for either pipe or box tube TKY CJP's. Notice the notes for corner weld macro-etch if box tube is used. Also, if the groove angles are less than 30° you may also need to see 4.12.4.2 and Figure 4.26 (And yet, those fall under the joints without backing section).

I think what your welders/contractor is thinking is that a welder qualified to 3G & 4G plate is qualified to weld pipe/box tube over 24". BUT not in TKY joints. So, The contractor is wrong and the client is right. Besides, the client gets what he wants most of the time, even if it exceeds the code, as long as it was specified in the Contract Documents, GSN, Job Specs, etc.

Oh, and WELCOME TO THE AWS WELDING FORUM!!

Have a Great Day, Brent

By welderbrent (*****)

Date 02-20-2013 20:41

They might argue that, but absolutely not. Welding a PJP from one side, then gouging it and welding a 'PJP' from the other side??? Is still a CJP TKY that requires the 6GR test for welders. :lol:

Have a Great Day, Brent

By 803056

Date 02-20-2013 22:04

I'm at a disadvantage being on the road without access to my copy of D1.1, but 6GR is a specific test required for open root CJP T, Y, and K tubular connections.

Check to see if I'm correct John and Brent. Look at the figure for the 6GR test configuration. It does not involve the use of a backing when making a CJP joint in tubular connections. A basic premise of D1.1 is that a prequalified CJP requires the use of backing or the second side is back gouged and welded to completion. In this case, the joint is back gouged and welded from the second side, so it qualifies as a prequalified joint assuming the joints are properly detailed. The welder can be tested on a standard butt joint with backing on plate or pipe because of the large diameter of the tubular connections involved.

Check my response, but I take the position the contractor can test his welders on plate with backing in both vertical and overhead using 1 inch plate. The welders are then qualified for all position, unlimited thickness, with backing or back gouged CJP groove welds, partial joint penetration groove welds, an all fillets. No 6GR required.

If the groove details are prequalified, the WPS is prequalified, thus the contractor is exempt from having to qualify the WPS using the 6GR coupons/position.

Best regards - Al

By welderbrent (*****)

Date 02-20-2013 22:38

I understand what you mean about the 6GR test Al but let's look at a couple of other things:
1) Clause 4 Part C- Performance Qualification; 4.18.1 Welders and Welding Operators. The qualified production welding positions for welders and welding operators shall be in conformance with Table 4.10.
2) When looking at Table 4.10 it has two columns for TYK Connections, one for 'Pipe' and one for 'Box Tube'. It then divides into two more columns for CJP's and PJP's under each of the others. The only test that qualifies for a CJP TYK regardless of backing or not is the 6GR per Figures 4.27 & 4.29.
3) Per footnotes the only other conditions are for angles less than 30° and box tube test must also consider the macroetch for the corners. (footnotes e, f, & g)

The only other considerations I made were as to plate qualifying for pipe over 24" in diameter. Footnote f also makes the same statement for using the box tube test that it qualifies for pipe over 24". So, basically, if you want your welder qualified for any CJP's in pipe or box tube in any configuration (TKY) with or without backing and/or backgouging you are required to use the standard 6GR test with pipe. If you use the box tube test you still won't accomplish qualification for pipe under 24" (not that that is an issue per this thread, my statement was to be qualified for all conditions).

I still take it to mean that their welders must be qualified to a 6GR test. In their case, either pipe or box tube would work.

My first thought was similar to yours but I don't believe that it will meet the code criteria. So, I guess it will be your turn to check it out when you have your book available. Meantime, if this OP is in any hurry for good counsel, I hope John and I have applied the code correctly.

Anybody else have any input?

Have a Great Day, Brent

By 803056

Date 02-21-2013 01:10 Edited 02-21-2013 01:13

I hate to respond to code questions without the code in front of me. There’s always a danger of shooting myself in the foot.

I do have a copy of the 2004 edition of D1.1. Generally it is recognized that text overrides a table or figure in the code. Again, remember I’m looking at the 2004 edition of D1.1, so the specific clause may be different. I am looking at clause 4.26 (4) and (5). They refer the user to figures 4.25 for qualifying the welder if the CJP T, Y, or K joint is made from one side with backing.

When the welder is qualified with backing, he is also qualified for welds make with back gouging.

There is an apparent conflict between the text and the table in the 2004 edition in that the text says the welder can be qualified for T, T, and K joints using a butt joint made with backing. However, the table listing the various positions qualified leads one to believe only the open root butt joint using different wall thicknesses is required (6GR). The text of the code states that the 6GR is permitted when the groove is not backed or back gouged.

Whether the welder qualifies with backing or whether he qualifies with the 6GR, the smallest dihedral angle for T, Y, and K joints is 30 degrees. Ithat is the case, T, Y, and Ks are covered even if a butt joint with backing is used to qualify the welder. It seems the problem is with the table listing the positions qualified.

I take the position that the table showing the limits of position qualified is in error.

I'll will look at this again when I get back to Connecticut, but that will be no sooner than early next week. I don't believe this poster wants to wait until next week for an answer. This is the type of question that should be submitted to the code committee for resolution. Especially if the most recent edition does not address the conflict that exists in the 2004 edition.

Gotta go.

Best regards - Al

By Shane Feder (****)

Date 02-21-2013 02:27

Hi guys,
Sorry Brent - I am with Al on this one.

4.27 CJP Groove Welds for Tubular Connections
Welder or welding operator qualification tests shall use the following details:

There is no weld detail for double sided welding so IMHO the nearest would be item (4). This would then allow welds to be backgouged in production.

(4) CJP groove T-, Y-, and K-Connections welded from one side with backing in pipe. Use Figure 4.24(B) in pipe of the appropriate diameter.

Figure 4.24(B) is a single vee with backing strip.
If you used pipe of appropriate diameter (7' - 2.1 mtrs) it would be as Al noted - almost the same as welding plate.

There is very little (if any) difference between welding large diameter piping in the 2G position with backing and welding plate in the 2G position with backing.

Then we go to Table 4.10.
If we go to Tubular - Groove - 2G then look in the Production Pipe Welding Qualified - T,Y,K connections - CJP column there is nothing listed, even though Clause 4.27 (4) clearly nominates it ?????

Then we go to Table 4.11
There is no mention at all of Figure 4.24 (a) or (b) for qualified thicknesses or diameters ????

(2) T-, Y-, and K-Connections.
This is from the Commentary
Because of the special skills required to successfully execute a CJP groove weld in tubular T-, Y-, and K connections,
the 6GR level of welder qualification for the process being used is always required (see 4.27).

IMHO there are no special skills required to weld a 7' diameter double sided weld in the 2G position,
Regards,
Shane

By welderbrent (*****)

Date 02-21-2013 12:02

Well, I'll throw some more wood on this fire looking at it from that aspect.

As the OP started to ask, it is just two PJP's if you want to excuse away the FACT that we are dealing with a TKY CJP and therefore the clauses previously posted are applicable.

Or, arguments I hear from shops that have many welders only qualified for fillets trying to tell me that a PJP is not a groove weld and is a fillet weld. Especially on skewed T joints. A slight skew is still a fillet but you reach a point where it becomes a PJP and is called out as such even on their shop drawings, but they try to get it welded out with guys only qualified for fillets.

So, my question, is it a CJP TKY falling under the above provisions or not?

Now, I do need to leave and get back up to my job and to my code book so I can check out Shane's references further and try to chase this down as to why we seem to have a discrepancy in the code. I have trouble believing this is that complicated. And, I am sure when Al gets a 2008 or 2010 book in hand the juices will start to flow. Until then, I may just be mudding the water I am attempting to throw on this fire instead of the wood that is being thrown on currently.

Have a Great Day, Brent

By Shane Feder (****)

Date 02-21-2013 12:24

Now we're talking.
What is a 14 mm deep penetration weld made from one side on a 25 mm plate ? - PJP
What is a 14 mm deep penetration weld made from both sides on a 25 mm plate ? - 2 x PJPs or 1 x CJP (by default) ?

Brent,
Understand where you are coming from regarding the Skewed T joints but they are dealt with in 3.9.3 and Clause 3.9 is titled "Fillet Weld Requirements".
Obviously as the angle gets greater they can turn into PJPs but I didn't investigate further,
Cheers,
Shane

By 803056

Date 02-21-2013 15:04

Skewed joints are neither a fillet weld nor are it a partial joint penetration groove weld. It is simply a welded skewed joint. There are a number of restrictions placed on the geometry and how the weld size is determined for a welded skew joint.

While the earlier editions of D1.1 used the term fillet welds in conjunction with skewed joints, you will notice in recent editions the use of the term "fillet weld" has disappeared when the dihedral angle between the adjacent members is less than 80 degrees (if I remember correctly).

As a matter of fact, in my opinion the fillet weld symbol is completely inappropriate for skewed joints. One basic premise of a fillet weld is that the weld be completely fused to the root. When the dihedral angle is less than 60 degrees, the Z-loss comes into play, i.e., we know there will be incomplete fusion. The concept of a fillet weld with fusion to the root is no longer expected, thus it is no longer a fillet weld.

What to do, what to do? Do I use a fillet weld symbol or a groove weld symbol? My response is that the standard welding symbols contained in AWS A2.4 simply does not accommodate the welded skewed joint. My recommendation is to sketch a cross section through the welded joint so the Z-loss can be shown and the required leg lengths can be detailed.

Throwing more wood on the fire, that's my task in life.

Best regards - Al

By welderbrent (*****)

Date 02-21-2013 16:50

I actually feel I have a pretty good understanding of the skewed, fillet, and PJP joints involved thus Al. My reason for the comparison was in how contractors try to get around restrictions on who is Qualified to weld a particular joint. And, in line with the ones in question, their own shop drawings detail all of them out good and when it gets to where they are a PJP they use the symbols for single bevel welds with bevel depth and weld size included and then include 'PJP' in the tail. They know when the engineer has designated it a PJP and yet try to get us to believe it is only a fillet weld.

Anyway, still haven't had a chance to take a more complete look at the references you and Shane have made in regard to the OP. Got to play in the snow and ice again this morning. Makes that 100 mile drive rather tense at times when I'm on the Interstate with .... idiots and truckers... sometimes one and the same.

Have a Great Day, Brent

By 803056

Date 02-21-2013 19:13

Drive safe!

Best regards - Al

By Shane Feder (****)

Date 02-22-2013 00:17

Al,
Will not disagree with you regarding skewed joints as you have probably forgotten more than I will ever know about D1.1.
However, I find statements like this in D1.1 very confusing
Table 4.11
Production Fillet Welds (T-Joint & Skewed)

2.3.3.6 Minimum Skewed T-Joint Weld Size. The
requirements of 2.3.2.8 shall apply.

2.3.2.8 Minimum Size. The minimum size fillet weld
shall not be smaller than the size required to transmit the
applied load nor that provided in 5.14.

Brent,
Does this interpretation help with your problem ?

Subject: Prequalified Skewed T-Joints
Code Edition: D1.1-79
Code Provision: Subsection 2.7.4, Figure 2.7.1
AWS Log: D 1 -85-026
Inquiry:
Response:
Are welds made in skewed T-joints, (e.g., Figure 2.7.1), where the groove angle is less than 60°,
accorded prequalified status?
Yes, Welds made in skewed T-joints, where the groove angle is less than 60°, are accorded prequalified
status provided that the welds are made with a prequalified joint welding procedure in
accordance with 5.1.1 and the welder is qualified for groove welding.

Regards,
Shane

By 803056

Date 02-22-2013 12:07

A word on using old interpretations, changes in the code's language may impact the original interpretation. Usually the code is revised to clarify, but there are time that might not be the case.

Al