https://app.aws.org/forum/forum.plAmerican Welding Society Forum - Technical Discussions15 Latest forum posts2024-02-29T14:26:02ZmwForumhttps://app.aws.org/forum/topic_show.pl?pid=288985Lamination - Welded Base PlateTimGary2024-02-29T12:55:19Z2024-02-29T12:55:19Z4 First, 0 tolerance for laminated plate in cyclic connections, period. Raw, uncut plate lamination scan inspections of materials to be used in cyclic connections make sense as an investment in scrap reduction. Meaning, if a lam scan is part of the receiving process, rejectable plates can be returned to the vendor without charge, as long as the material has not been cut or damaged by the receiver. When a plate does make it through to being cut before a lamination is detected, 0 tolerance means scrap the plate or at least laminated sections of the plate, so that material investment is lost. When it comes to 100% undoubted static connections, reality is that lamination is not really a problem, even though most weld codes will call for rejection. Any code restriction can be over ridden by the Responsible Technical Authority, most often the Design Engineer over the project. This carries a lot of risk for the signers of the necessary documentation, and may also require approval from the Customer's and/or End User's Engineer, so it's not often done. However, it does make business sense to use already purchased materials somewhere, rather than scrap, if it can be properly controlled. One way is to use it for temporary construction aids that shall not be included in salable product. Another way is to approve it's use for guaranteed static connections. Also, it can be used for weld training purposes. I guess the point is 0 tolerance for cyclic connections shouldn't have to mean 100% scrap of laminated materials.
Tim]]>
https://app.aws.org/forum/topic_show.pl?pid=288982Lamination - Welded Base PlateDistilled2024-02-27T19:28:13Z2024-02-27T19:28:13Z4https://app.aws.org/forum/topic_show.pl?pid=288981Lamination - Welded Base Platejwright6502024-02-26T12:26:24Z2024-02-26T12:26:24Z4https://app.aws.org/forum/topic_show.pl?pid=288980Lamination - Welded Base PlateJovi Zhu2024-02-26T07:56:36Z2024-02-28T03:00:43Z4
I appreciate your thoughts especially the thinking of whether the judgement is fair to the vendor.
"Zero Tolerance" from buyer is sometimes a cover of strict quality control with a core of "not capable or willing to bear any risk". From the seller's side the mill is not capable either to calculate and consider the service condition to convince and guarantee the serviceability of the plate to serve the customer.
Most commercially available structure steel plates are rolled and the inner imperfection will become planar lamination of different degree, however for the most cases this is not harmful since the service load are usually parallel to the lamination. (or I can even say it is even benifitial for some cases as the lamination increases the "surfaces" within the thickness to make the plate "stronger" same as why a wiresteel is stronger than a rod of the same size.)
ASTM A20 also gives some acceptance critera for "edge imperfection" but after further rolling or welding if laminar tear is detected, no one from the buyer's side wants to say it is acceptable.
This is a grey area where buyers are not paying for a perfect defect free melting process while sellers are still supplying commercial quality level plates.
Just some thoughts.]]>
https://app.aws.org/forum/topic_show.pl?pid=288979Lamination - Welded Base PlateDistilled2024-02-23T22:07:01Z2024-02-23T22:07:01Z4 I'm familiar with ASTM A435 and it's evaluation technique and acceptance criteria and I've read D1.1:2020's sections regarding mill induced discontinuities as well as the related commentary, but it is pretty specific to those visible in cut surfaces. I also understand the concern particularly with lamination type discontinuities which have a plane that is perpendicular to tension, such as in a t-joint. Specifically in my case we're dealing with base plate to pipe or tube connections; CJP welds using static loading design criteria.
So, the question is, has anyone seen or been involved with the development of accept/reject criteria where this condition exists at this type of connection? Is it even feasible to consider that some indication of a lamination is not detrimental in this type of joint and tension?
Thus far I've argued that there should be zero tolerance for lamination or de-lamination as it were, and my Engineering Team agrees and any plates having indications found during straight beam UT inspections near or at the weld root out to the center line of a bolt hole pattern are quickly rejected. We're not necessarily sizing the area of the indication or attempting to apply some level of reflected signal amplitude to determine the severity - zero tolerance - period.
On one hand I completely get it... on the other hand I'm not sure if we're being fair to our vendor or the mill. :) I've included a photo; 1-1/2" plate, indications consistent at approximately .730" to .760", but primarily we see several spots very very close to .750". There is a pretty consistent reflector throughout the plate, but in places I can peak at 30% to even 50% screen height with my back reflector at 100%. To me that is excessive, but should there be SOME tolerance for smaller indications??
I'd love to hear some feedback and fresh opinions on the topic. Thanks in advance.
Shoot - - can't figure out how to insert a photo.
Cheers.]]>
https://app.aws.org/forum/topic_show.pl?pid=288978T-Joint Gaps - Fillet WeldDistilled2024-02-23T21:46:51Z2024-02-23T21:46:51Z14https://app.aws.org/forum/topic_show.pl?pid=288939CAT D NDEHAFHARVARD2023-10-17T23:48:50Z2023-10-17T23:48:50Z0https://app.aws.org/forum/topic_show.pl?pid=288925weld symbol on drawing meaningJovi Zhu2023-10-08T12:21:54Z2023-10-08T12:21:54Z6 The boiler industry Codes/Standards gives requirement for joint preparation and some company has its own joint design manual with details more than what the AWS A 2.4 "V" symbol can stand for.
Tube/pipe butt welding in the industy does not need the "weld all around" symbols at all, as all welders know the whole girth must be welded.
Most manufacturers has their system using WPS (ASME I&IX and EN12952 makes this almost mandatory) or equivelant documents to specify the electrodes other than by drawing symbols. Some European companies list welding electrodes, preheat & interpass temp., heat treatment, etc. in a table on drawings for each joint number but not using welding symbols to specify.
It happens when you have to fabricate a replacing part for a very old boiler then such old drawing is found. It may be difficult to find the original designer to intepret but if the contractor has the due expertise in the industry (s)he may re-design it with judgement of the suitable welding requirement.
Good luck.]]>
https://app.aws.org/forum/topic_show.pl?pid=288924weld symbol on drawing meaningsandeepkumar632023-10-06T15:32:12Z2023-10-06T15:32:12Z6 The ultimate aim is to produce a quality weld and as long as you follow the best practices such as good weld preparation, root gap welded with TIG to create a good root fusion, there is no issue at all. As a Cr-Mo steel, you have to do the PWHT of this joint.
The weld-all-around symbol or also called Peripheral weld is used to represent a weld that encircles a group of interconnected joints. In simple weld, a Weld around Symbol shows a weld that is made all around the weld location. This symbol is in the form of a circle placed at the intersection of the arrow and reference lines. Reference:https://learnweldingsymbols.com/weld-all-around-symbol/]]>
https://app.aws.org/forum/topic_show.pl?pid=288892weld symbol on drawing meaningLawrence2023-09-08T12:02:00Z2023-09-08T12:02:00Z6 But perhaps the company that provided the drawings are aware of their 20th century standard detailing practices and can answer all your questions.]]>
https://app.aws.org/forum/topic_show.pl?pid=288891weld symbol on drawing meaningTimGary2023-09-07T11:48:55Z2023-09-07T11:48:55Z6
The most important part of the drawing is noted in the bottom left hand corner which states "If in doubt, ask." This means you need to direct questions to the entity that provides the drawing. Any guidance you receive from others may be misleading.
Tim]]>
https://app.aws.org/forum/topic_show.pl?pid=288890weld symbol on drawing meaningpradeep4u2023-09-07T05:12:08Z2023-09-07T05:12:08Z6
I am attaching another drawing and here also pipe to pipe welding has same symbols. Please throw light on it Regards Pradeep]]>
https://app.aws.org/forum/topic_show.pl?pid=288889weld symbol on drawing meaningTimGary2023-09-06T17:35:22Z2023-09-06T17:35:22Z6
If it were and AWS A2.4 welding symbol. the 5 to the symbol left would be the groove depth, the 40 to the right would be the weld length and the circle at the reference line and arrow junction would mean "weld all around". The dash ( - ) between the weld symbol and weld length (40) is not an AWS utilized symbol. The (E8013B2) may be an electrode designation, but an AWS A2.4 welding symbol could have that info in a tail at the end of the reference line, which is not included in your example. The D34 below the reference line is not an AWS designation. I see no designation on the drawing provided to state a weld or welding symbol specification or units of measurement. The sad truth is that every engineering office has its own opinions on welding symbols and whether or not to use standard AWS or ISO symbiology. This symbol does not fully match either, so the only one who can accurately define what is meant is the one who drew the symbol.
Tim]]>
https://app.aws.org/forum/topic_show.pl?pid=288888weld symbol on drawing meaningpradeep4u2023-09-05T12:19:14Z2023-09-05T12:19:14Z6
Please tell me the meaning of welding symbol in red circle in drawing attached]]>
https://app.aws.org/forum/topic_show.pl?pid=288886T-Joint Gaps - Fillet Weldjwright6502023-08-24T11:19:08Z2023-08-24T11:19:08Z14 D1.1:2015, Clause 5.21.4.2 Correction. Root openings greater than allowed in 5.21.4.1, but not greater than 3/4", whichever is less, may be corrected by welding to the acceptable dimensions prior to joining the parts by welding.
Next Clause speaks to doing this with the EOR's approval only.
Thanks again for bringing up this, the use of nonstandard terms get us in trouble sometimes, when everyone has a difference use of the term.]]>