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Up Topic American Welding Society Services / AWS Learning & Education / Corner to Corner Joints (No overlap)
- - By Tyrone (***) Date 04-07-2004 14:12
Hiya,
I'm looking for the weld symbol to put on a drawing. I cannot find any examples in the AWS 2.4 relating to putting a single sided, (outside corner), weld symbol.

I've seen both fillet weld and single V-groove weld sybols used on various drawings.

Any reference documentation would be appreciated.

Thanks
Tyrone
Parent - - By ssbn727 (*****) Date 04-07-2004 14:54
Hi Tyrone!
Are you referring to a square groove weld symbol???

Respectfully,
SSBN727 Run silent... Run Deep!!!
Parent - - By Tyrone (***) Date 04-07-2004 15:42
Not a square groove, 727... the fit-up is corner to corner, where there is a 90 deg. shelf, (outside corner), to put in a weld.

If anyone wants a sketch, I can email you one. Contact me at chint@gdls.com
Thanks
Tyrone
Parent - - By thcqci (***) Date 04-07-2004 16:41
Do you desire a CJP joint? As suggested, it seems to me to be a joint with less strength than overlapping the corner and putting a groove in it. Groove would not develop full strength of plates due to geometry. Further it would not be a prequalified joint. See BTC-P4-xx or TC-U4x-xx in AWS D1.1. Joint could be either PJP or CJP. Suggest one of these or similar joints be chosen instead.
Parent - - By Tyrone (***) Date 04-07-2004 17:08
thcqci, thanks for the response, it got me thinking. Yes I need CJP since it is welded on one side only.

I am trying to design joints without prep. (reduce costs). 1/4" mild steel plates fitted together at 90 deg. I would agree to joints BTC-P4 or TC-U4 on plates over 3/8" thick, to avoid multi-pass welds on an outside corner.

I disagree that the corner joint weld will be not as strong as the plates. On the contrary, the weld metal (70, 000 psi yield weld wire) will be at least twice as strong as the mild steel plates.

Thanks for your insights
Tyrone

PS - Outside, single sided weld, corner to corner. Is it a groove weld or a fillet weld?

Parent - - By DGXL (***) Date 04-07-2004 17:37
Tyrone:
By definition (yours) this would be a fillet weld deposited on an outside corner joint. This can be performed with a full pen. fillet weld from the outside, but requires qualification in accordance with D1.1. I have qualified joints with this weld before, it's not too difficult. One note, positioning of the part is paramount to achieving the required penetration and code required weld profile.

I agree to disagree that the joint does not achieve "full strength". The direction of loading would determine the validity of that statement. Does this mean any corner joint does not develope "full strength"?

I do not agree that the welding electrode developes 70 ksi yield, the 70 is the minimum tensile strength of the electrode as noted in the applicable specification.
Parent - By Tyrone (***) Date 04-07-2004 18:00
DGXL,
I stand corrected. 70, 000 psi ultimate. Therefore, as long as the weld throat is equal or greater than the plate thickness, full strength is aquired.
"Does this mean any corner joint does not develope "full strength"? Not at all. Specifiying a minimum weld size means that overloading the joint (in any direction), will result in the parent material failing before the weld metal. There's bigger problems when that happens.

Thanks bud,
Tyrone
Parent - By ssbn727 (*****) Date 04-08-2004 03:06
Hi Tyrone!
Okay! Now that how you've clarified the joint geometry,I've got a better understanding of what you're looking for...

It seems that you've got the best advice from the rest of the "fellas" regarding your situation so, I only have a few questions for you...

What process and position are the welds dpeosited with for this or these joint(s)?
Do you know What filler material are you going to use for what specific composition of mild steel?
Finally, what is the intended purpose and in what type of application is this joint going to be used for? In other words, what type of loads will this structure be subjected to that would require CJP on an "outside corner single sided" joint to be welded from the outside only, just out of curiosity? I ask this because sometimes, saving time and money does'nt always work out in the end result - if you understand where I'm coming from...
Respectfully,
SSBN727 Run Silent... Run Deep!!!

P.S. send me a sketch, E-mail: hanklive39@hotmail.com
Parent - - By CHGuilford (****) Date 04-07-2004 16:52
I'm not sure of what you are describing but you don't HAVE to use a standard weld symbol if it doesn't really describe the joint. Instead, you could draw an arrow and reference line with a note to "SEE DETAIL...........". That is also valid method for showing welding symbols.

Chet Guilford
Parent - - By Tyrone (***) Date 04-07-2004 17:13
You are correct Chet. I have to draw the detail of the joint to show Production the joint configuration. I would like to have a weld symbol for prosperity.
Thanks
Tyrone
Parent - By jwright650 (*****) Date 04-08-2004 10:12
Is it possible to revise the joint at the corner to run one by and stop the other short to achieve a true corner joint which you could then use a prequalified CJP joint detail like the TC-U4a.
just a thought,
John Wright
Parent - - By pipewelder_1999 (****) Date 04-07-2004 21:38
By the definitions of both fillet welds and groove welds, either could be used. If you are going to require full penetartion, use a single vee groove symbol. Even though complete penetration can be achieved you will not get a full throat thickness at the joint. You will have an effective weld throat of .707 of the base metal thickness.

The joint could be backed with formed backing on the inside corner to allow the melt through to form a reinforcing fillet on the back side.

I may look in some other sources regarding the "overlap" of these terms and symbols.

Have a nice day

Gerald
Parent - - By thcqci (***) Date 04-08-2004 12:10
Tyrone, your post says you are welding from one side only. Unless I have always interpreted D1.1 wrong, you will need a backing to achieve a "welded from one side only" CJP weld as AWS does not recognize CJP welds without a backing. Without backing there must be a backgouge, etc. to sound metal and then deposit more weld metal.
Parent - - By Tyrone (***) Date 04-08-2004 13:31
Morning guys, had a great nite sleep thinking all about weld joints. Hahahaha.

You've all made valid points. I've re-done the calcs, (70, 000 ultimate....right), on this corner weld using effective throat. Structurally, the parts and weld will take the shear loading with a good safety margin.

I guess I won't specify CJP (no backing), but will get full penetration naturally anyway.

I have my heart set on this config. I'll probably specify a single sided fillet weld unless someone convinces me otherwise....

Thanks
Tyrone
Parent - - By DGXL (***) Date 04-08-2004 15:36
thqci:
You have not interpreted the code wrong, but there are exceptions. Check out D1.1:2002, section 4.12 (4.12.2/4.12.4) as an example.

Tyrone:
I mentioned above I have qualified a similar joint detail under D1.1 several times in the last few years. Corner joint, CJP - single pass fillet weld w/o backing. The test/acceptance criteria was cutomized for each application. The RDP in each case approved the joint/weld detail as well as the test/acceptance criteria that had to be developed for each weldment. The local building dept. plan check also had to approve these, which they did. The of the above weldements were subject to shear/compression.

Often I use the B2.1 specification for welds like this that do not comply with the code or specification normally used for a particular type of service. I enjoy projects off the beaten path that most of my competitors say cannnot be done.
Parent - - By bmaas1 (***) Date 04-08-2004 16:31
Is this exception only for tubular connections? I thought you could qualify for full pen while welding from one side with no backing or gouging.


Brian J. Maas
Parent - - By thcqci (***) Date 04-08-2004 20:46
I based my above stated opinion upon the verbiage in AWS D1.1 2004:

"3.12.1 Definition. Except as provided in 3.13.4 and Figure 3.4 (B-L1-S), groove welds without steel backing, welded from one side, and groove welds welded from both sides, but without backgouging, are considered PJP groove welds."

3.13.4 deals with tubular T-, K- and Y- joints in tubular connections. The above referenced exception would apply there with welding procedure qualification and welder qualification. B-L1-S is a SAW square butt weld with a 3/8"max. thickness. Since it is a pre-qualified joint, no procedure qualification required.

Thus, in my opinion, the above desired joint cannot be considered CJP unless backing is used or backgouging is performed.
Parent - - By thcqci (***) Date 04-13-2004 17:39
As I am reading my new D1.1:2004, 2.17.1 also allows one-sided groove welds of ..."(1) Secondary or nonstress carrying members; and (2) Corner joints parallel to the direction of calculated stress between components of built-up members." I would presume that these members must be outlined on the fabrication drawings and reviewed/approved by the SER.
Parent - - By jwright650 (*****) Date 04-13-2004 17:57
I saw that too. But did you notice that this "Part C" is for Nontubular Connections(cyclically loaded)? Why isn't this addressed back in "Part B", that is for Nontubular Connections(statically loaded)?
John Wright
Parent - - By swnorris (****) Date 05-11-2004 14:14
John,

My interpretation and understanding of this is that welds in a nontubular cyclically loaded structure are more subjected to notch potential and fatigue crack initiation than welds in a nontubular statically loaded structure. Notch potential and fatigue crack initiation possibilities have been reduced in nontubular cyclically loaded structures by specific requirements which may be allowed in static loads, but prohibited in cyclic loads, much like the reasons for the need for removal of backing or runoff tabs in cyclically loaded structures. As you probably know, statically loaded structures are subjected to very little load changes or movement, and cyclically loaded structures are subjected to recurring loads. These recurring loads significantly raise notch potential and the possibility of crack initiations. My problem here is that I can't get anyone to tell me whether a project we're fabricating is cyclically loaded or statically loaded, or they're not willing to pick up the phone and call someone who does know, so I have to treat it as worst case scenario. I hate to think that I waste shop labor on treating everything as cyclic, but I don't see where I have much choice. Since I am responsible for everything that goes out the back door, I have to cover my butt. I'm wondering as I write this, do any of you guys have the same problem?
Parent - - By jwright650 (*****) Date 05-11-2004 15:42
Scott,
I was just wondering why the Paragraphs in 2.17 listing "prohibited joints and welds" don't show up until you get to Part "C" dealing with cyclically loaded non-tubular connections. Are these only prohibited without qualifying to Section 4 only for cyclically loaded non-tubular connections or for all connections?

Do you take this to say then, that one sided joints without backing are OK without qualifying to Section 4, as long as they are not cyclically loaded non-tubular connections? In other words Prequalified?
Confused,
John Wright
Parent - - By swnorris (****) Date 05-11-2004 18:34
Hi John,

I interpret that the referral in 2.17.1 to one sided "groove welds made from one side without backing" is meant towards pjp, which is prequalified (3.3), but prohibited on nontubular cyclic loads unless it can be applied to either (1) secondary or nonstress carrying members, or (2) corner joints parallel to the direction of calculated stress..., as indicated in 2.17.1.
However, I think the referral to "made with backing other than steel, that has not been qualified in conformance with Section 4" indicates that if a different backing, such as copper or ceramics is used, and is applied to a nontubular connection in a cyclically loaded condition, and its application is for something other than (1) secondary or nonstress carrying members, or (2) corner joints parallel to the direction of calculated stress..., as described in 2.17.1, it is not prequalified, and therefore is subject to the requirements and qualification tests in Section 4.

After I finished with the above response, I looked back to my D1.1 2002 code and saw that all the words in paragraph 2.17.1 were underlined, which indicates changes from the previous code.

Then I looked at D1.1 2000 and found that Prohibited Joints and Welds were in 2.27, which states the following in 2.27.2 with regard to one sided groove welds:

Groove welds, made from one side only, are prohibited, if the welds are made:

(1) without any backing

(2) with backing, other than steel, that has not been qualified in accordance with section 4.

These prohibitions for groove welds made from one side only shall not apply to the following:

(a) Secondary or nonstress carrying members and shoes or other nonstressed appurtenances, and

(b) Corner joints parallel to the direction of calculated stress, between components of built up members designed primarily for axial stress.

I think that in D1.1 2004, in 2.17.1, the statement “made with backing other than steel, that has not been qualified in conformance with Section 4" is what's confusing. If you go back to the D1.1 2000 code, to 2.27.2, item (2), it is more clear and precise.

The groove welds that are prohibited by 2.17 do not perform well under cyclic loading, but are permitted in other applications. The exceptions indicated in 2.17.1 items (1) and (2) are because welds in secondary members are not subjected to cyclic stresses, however for loads subjected to cyclic activity, the unwelded side constitutes a stress raiser significance when fatigue loads are applied transversely to the joint, which is why it is imperative to remove backing in these applications.





Parent - By jwright650 (*****) Date 05-11-2004 19:57
I understand and agree with your method of thinking toward cyclically loaded conn's. I was hoping that D1.1 would have kept "prohibited joints" in a "general section" that would apply universally and then specify further at cyclically or non-cyclically loaded conn's.
John Wright
Up Topic American Welding Society Services / AWS Learning & Education / Corner to Corner Joints (No overlap)

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