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Up Topic American Welding Society Services / Certifications / D1.1 Weave width restriction??
- - By devo (***) Date 09-27-2012 02:22
I've searched the forum already, so please don't fuss, but I need an answer.  The Instructor I work under says that D1.1 had a revision this year that limits the bead width to 1-2x electrode diameter for stringers, and 3x electrode diameter for weave beads.  This seems to be quite restrictive, but what do I know???   So my question to you D1.1 gurus is ..... Is there a restriction on bead width?  I always heard(and read over and over on this forum) that D1.1 has nothing to say regarding bead width.   And how the hell could you make a 3/32" bead with 3/32" 7018 electrode?
Parent - - By aevald (*****) Date 09-27-2012 06:20
Hello devo, I'll bite and say that there is not restrictive language to support your instructors position. There has been exhaustive posting of both opinions and various code related language to describe and address this area. ASME has been discussed relative to this, API, CWB, ABS, D1.1 and any number of others. In most cases the actual codes are pretty much mum with regard to putting out limitations. Rather it has been more likely that WPS's, WPQR's and other supporting and dictative documents are where limitations might be seen. Many of those limitations might come from material types, uses, and other mechanical or metallurgical issues that would influence restrictive bead width language.

I am pretty sure others will reply and with much more finesse and detail than I have, yet I also believe they will essentially tell you the same thing. I will await the replies of others for further clarification. Good luck and best regards, Allan
Parent - - By devo (***) Date 09-27-2012 10:43
I've read the exhaustive postings you referred to, but the instructor I work under is getting his information from Carl Smith, who sits on the AWS education committee and is a regular contributor to the Fabricator magazine.  So it is coming from a very reliable source, I just wonder if somehow something is getting lost in translation.  Could he be referencing the maximum leg size of a single pass fillet?
Parent - - By Lawrence (*****) Date 09-27-2012 10:51
The only reliable source is the code book   :)

Just plop the code book in front of your chief and ask him to point it out to you so that you can share his golden nuggets of wisdom verbatum with your charges.

He will solve the problem himself  :)

Teachers can be taught... you just need to smack them across the nose with a 3" thick code book to do it.
Parent - - By js55 (*****) Date 09-27-2012 19:05
I'm with Lawrence. Don't drop names, show me.
Parent - By 99205 (***) Date 09-28-2012 03:27
Exactly, show me.  I try to take the diplomatic approach, just to save someone from unnecessary embarrassment.  "Could you show me that Clause in the code book, so that I can make notes for future reference."  I've had to do this again, recently.  I never fails to amaze me how many people have D1.1 memorized, kind of.
Parent - By pipes (**) Date 10-08-2012 17:45
HAHAHA! Smack 'em with a 3" code book.... I love it!
Parent - - By Superflux (****) Date 09-27-2012 12:33
Again I will give my QC Commandment #1
"Thou shalt NOT quote the code without the book open and reading from it!"

Could he be referencing the maximum leg size of a single pass fillet?
Now there's one I would really like to see; a fillet weld leg measured by "rod width". I think this is most likely measured in inches (fractions/decimals) or millimeters.
Parent - - By Superflux (****) Date 09-27-2012 12:40
how the hell could you make a 3/32" bead with 3/32" 7018 electrode?

According to the new Farm Code supplement, I believe it requires weld widths to be measured by rods with the flux on.
Just DO NOT let a savvy inspector try to shoot you down for undersized welds made with an E6013 by measuring it with 2 E7024s!:confused::evil:
Parent - By qcrobert (***) Date 09-27-2012 16:09
:lol::lol::lol:
Parent - By Lawrence (*****) Date 09-27-2012 14:34
Fillet schmillet!
- - By 803056 (*****) Date 09-27-2012 19:51
I have encountered "welding engineers" that spout rubbish, so why shouldn't the welding instructor tell the same fairy tales. The fundamental expressed is right up there with preheating to drive moisture out of the steel before welding.

Another comment that comes to mind spoken by a “welding engineer”; “We do not weld with GTAW, we only use “Heliarc”. Same individual; “We never weld autogenously, we make dry pass welds.”

Several years ago I had the pleasure of conducting a training course for a large fabricator in the Midwest. I spent time with 108 welders, both in the classroom reviewing theory and D1.1 as well as on the floor to improve welding skills. The question was raised which was better; a large single pass fillet weld or the same size fillet weld made with multiple stringers. I let the welders answer the question by welding samples in the vertical position, each with a 3/8 inch fillet weld. Then they had the pleasure of breaking the T-joint with a 10-pound sledge. We also compared the resulting angular distortion caused by the two methods. The results were unanimous, all 108 welders agreed on which technique produced the “better” results based on the number of blows required to cause the weld to fail. They also agreed on which technique resulted in the most angular distortion. The population size meant the experiment met all the requirements of a statistical experiment with a large population size. Good stuff. 

Best regards – Al
Parent - - By devo (***) Date 09-27-2012 20:53 Edited 09-27-2012 21:12
So which method did the 108 welders prefer??  The conventional wisdom says the weave will provide less distortion, whereas the grain refinement provided by the stringers gives a little better strength (although on A36 is there any difference?).  I am just the adjunct instructor, mostly teaching welding to folks who aren't in the welding program, but I still want to teach proper methods.  And although I've learned a bit about diplomacy when it comes to disagreeing with folks, I won't back down when I know I'm right.

P.S. Everyone knows that to make dry pass welds you need to drive the moisture out of it first.  Duh!:grin:
Parent - - By 803056 (*****) Date 09-27-2012 20:58
Well Devo, the definition of "better" comes into play.

I defined "better" as being the number of blows required to cause the weld to fail.

You stated the multiple pass technique should result in a "stronger" weld.

Before answering with the conclusions drawn by my 108 experienced welders, let me ask you a question: "What is the relationship between "strength" and "ductility"?

Ponder on this one a while before you provide me with your response.

Best regards - Al
Parent - - By devo (***) Date 09-27-2012 21:14
The stronger weld would probably break first, since there is typically an inverse relationship between strength and ductility.
Parent - - By 803056 (*****) Date 09-27-2012 21:17
You hit the nail on the head, so which characteristic would be preferable, strength or ductility?

Best regards - Al
Parent - - By devo (***) Date 09-27-2012 21:43
I'll take the ductile weld thanks.
Now to hijack my own thread...what is the mechanism responsible for the "mass effect" in tensile tests.  Given two tensile test specimens from the same material but of different cross sectional areas, the smaller one will break at a higher force than the larger one.  Why is this so?
Parent - - By 803056 (*****) Date 09-27-2012 21:51
Plastic flow and strain hardening occur more easily in smaller sections. In thin sections dislocations pile up more easily and resist further plastic deformation, i.e., strain harden.

Thicker sections behave in a brittle fashion when compared to thinner sections. In thick sections the dislocations pile up at the tip of the defect where failure is initiating, but they are localized and do not affect the cross section to the extent they do in a thin section. Thus strain hardening is not as effective when compared to the thin section.

Hey, that's my guess for the day.

Best regards - Al
Parent - - By devo (***) Date 09-27-2012 21:57
So a tensile specimen of infinitely small cross section is unbreakable right?  Maybe NASA could use a bunch of them to make their space elevator.
Parent - - By 803056 (*****) Date 09-28-2012 03:13 Edited 09-28-2012 03:38
You might be on to something.

It parallels the definition of an expert. An expert is someone that knows more and more about less and less until he knows everything about nothing.

Al
Parent - - By eekpod (****) Date 09-28-2012 19:38
getting this back on track...
I hate how some inspectors/ engineers, others who think they know it all spout out some kind of phrase with full authority and entitlement to the effect...."as I'm sure YOUR WELL AWARE the code only allows blah blah blah" and they give you that look like you better agree with me or you don't know what your talking about.

Basicallly, ask your instructor nicely what page and line so you will know it for the future.
good luck
Parent - - By 803056 (*****) Date 09-28-2012 19:44
Good advice. Never try to show up the instructor or the boss. That's called "job suicide".

Al
Parent - - By devo (***) Date 10-03-2012 01:25 Edited 12-10-2012 03:40
Update...it was all a misunderstanding.  What the CWI was explaining as a rule of thumb (weave width as it relates to electrode diameter) was misunderstood by the instructor to be in the D1.1 code.  That's what happens when you ask a question on voicemail and get the response by voicemail.  And before you all get the wrong idea and go bashing the instructor (Ron) or our resident expert (Mr. Smith), read his reply to my query....

     Mr. Yates, I didn't say the info was in the code. I don't quote the code often, but I do know where to look. I told Ron that it is recommended practice. (Rule of thumb) I would never allow my welders (I have supervised several) to exceed the recommendations that I gave to Ron.

If you are giving a guided bend test, you are lowering the passing possibilities by wider weaves or even wider welds for that matter. Take into consideration the yield and tensile strength of the electrode and you will realize that the poor old A-36 plate is already losing the "tug of war" battle. The average yield for an E-7018 electrode is around 58 to 65 KSI. The yield for the A 36 is around 36 to 38 KSI. The yield is reached for the electrode as soon as it solidfies. You may very often see the stretch marks in the HAZ before you begin to prepare the coupon for testing. If it were not for the ductility belonging to the A-36, the weld would fail as soon as it is made.

The codes will tell you what the maximum depth of weld made in one pass can be. For instance, the ASME Code allows a single pass weld with Sub Arc to be 1/2" thick. An .035" GMAW wire is allowed to produce a 1/4" weld in one pass.

The D1.1 Code does however, offer a suggestion and a mandate about the ratio of width to depth of a groove weld. The maximum (and minimum) size fillet weld that you refer to is based on the material thickness Not the amount of weave or electrode size!

As for your question about how to achieve a weld bead equal to the electrode diameter, the speed of travel will determine bead width. Also that is dependent upon the type of electrode. The E-7018 low hydrogen will produce a bead wider than its core diameter. If an E-6010 is deposited as it should be (with a whip and pause technique) one can nearly double the width of the electrode. I am aware of a company in Sistersville that welds small piping components and they make 3/32" welds with a 1/8" electrode all day long. Of course the pipe is turning on a positioner. Regulation of the travel angle also controls the bead width. The greater the travel angle in the drag direction, the smaller the bead may be produced. If a "push" angle is used, the bead will be wider.

In the case of GMAW, amps to volts ratio becomes a factor. The higher the voltage to amperage ratio, the wider and more shallow the bead becomes. If the amperage is on the high end of the ratio the bead will become tall and narrow.

My answer to the questions are to use good judgement in the production of a weld. The wider the bead, the more residual stress is built into the weld-so even before external stress is applied, the weld has aching muscles. A good inspector can differentiate the "hog weld" from a suitable weld. A good welding technician will not tolerate a bead that is unnecessarily wide. It will be sent back to the drawing board. If it extends about a sixteenth of an inch beyond the bevel, it will look and act OK.

These things have been argued and discussed for ages and I don't have a feeling that everyone will EVER agree. My advice is to go to an ASME code pipe shop to see what they do and go to an AISC approved structural shop to see what they do and follow suit. (The AISC uses AWS codes, D1.1, D 1.5, D 14.3, etc.)

Professor xxxxxxxxxxxxxxxxxxxxxx
AWS CWI, CWE, NDE Level III
AWS Education and Certification Chair

Sounds good to me...
Parent - - By 803056 (*****) Date 10-03-2012 04:06
There are a few things I can take issue with, including but not limited to a few references to code requirements.

The reference to the 1/2 inch layer thickness is not limited exclusively to SAW.

The width of a weave bead using low hydrogen SMAW electrode is not restricted by AWS D1.1, however, if the limiting size of a vertical single pass fillet weld is 1/2 inch, then the width of the weave is on the order of 5 times the maximum electrode diameter and more if smaller electrode diameters are used. The width of an individual weave bead deposited by SMAW is not limited, however the thickness of the layer is. We do differentiate between a weld bead and a weld layer. The width of a layer for FCAW and GMAW is limited by the requirement that a split layer be employed with the width of the previous weld layer exceeds some value.

I have welded many 1 inch thick test plates where the width of the cover layer was on the order of 1 1/4 inches. The cover and most intermediate layers were deposited as weave beads. I had no difficulty passing the requisite guided bend tests that are required to achieve 20% elongation.

Regarding angular distortion; when qualifying on a grooved plate, regardless of the electrode classification, welders that deposit numerous stringer beads to fill the groove invariably have more angular distortion then the welder that uses wide weaves.

It has been my experience that as demonstrated by fillet break tests, a single pass fillet weld, up to and including the largest single pass fillets permitted by AWS D1.1, invariably exhibit better ductility than multipass fillets of the same size.

Having expressed my opinion on the matters noted I see no reason not to use good judgment when teaching students how to weld. Any practice carried to extremes can produce less than desirable results. However, I cringe when someone uses the code to substantiate their position when the restriction is not in the code cited.

Best regards - Al
Parent - - By Lawrence (*****) Date 10-03-2012 12:55
When it comes to teaching there is a time for both opinion and fact.

The fact is that in the real world, our students may be called upon to do both weaves and stringers...

Why?  Because some projects have heat input restrictions and weaves take longer to get from point "A" to point "B"...  Some contractors prefer weaves over stringers or visa versa... It doesn't really matter why...  Both "may" be compliant in some cases.

So it just makes sense to teach both stringers and weaves with FCAW, SMAW and GMAW (short circuiting).

I expect my students to master both and inform them that there may be times when either may be required out there in the real world and sometimes it's dealers choice if the WPS is silent...... But if there is a limitation that it's an engineering level decision that will be reflected in the WPS and shall be obeyed.
Parent - By 803056 (*****) Date 10-03-2012 13:11
I agree that both techniques should be taught and mastered. My objection is citing the restrictions as being code requirements when in fact the requirement or restriction is nonexistent. A restriction may be imposed to ensure heat input criteria are met. That is usually addressed by the code(s) as a supplemental variable that apply only when notch toughness is a requirement, i.e., a special case. Even then, the code restriction is imposed on the heat input or interpass temperature, not the width of the weld bead.

As you noted, the employer uses the WPS  as the vehicle that provides specific information to the welder such as travel speed, arc voltage, amperage, wire feed speed, etc. Bead width is sometimes used to limit travel speed, but I often wonder if the bead width limitation is based on data or if it is simply a case of "that's how we always do it." I believe the latter is the case in most organizations.

Best regards - Al
Parent - - By Blaster (***) Date 10-03-2012 14:28
Heat input issues aside, I have seen vastly more vertical stick plates fail bend tests when run with stringers due to lack of fusion than I have seen fail from lack of fusion or slag inclusion when running weaves.  It seems many welders run a very low level of current in order to control the bead shape with stringers.
Parent - By 803056 (*****) Date 10-03-2012 14:30
So true; when restricting the discussion to carbon and low alloy steels.

Al
Parent - - By jwright650 (*****) Date 10-03-2012 15:00
I cut up a pretty 3G SMAW coupon several days ago and the backing bar actually fell off and I had to look around in the saw chip tray to find it. I sent it back to the welder so he could see what happened to his test sample and can adjust his technique for the lack of penetration into the backing strip.
Parent - - By 803056 (*****) Date 10-03-2012 19:10
So, did he use a weave or stringer technique?

Just asking.

Al
Parent - - By jwright650 (*****) Date 10-03-2012 19:19
that one was a weave.
Parent - By 803056 (*****) Date 10-03-2012 20:04
I had a similar situation with a 3/8 inch test plate that passed RT. When I picked up the plate I could see daylight between the backing bar and the test plate. I cut off the tacks at the very ends and the backing fell off. I guess there is no substitute for skill.

I still have that test plate in my collection. I use it for VT, PT, and MT demonstrations. I should use it for UT as well. The incomplete fusion is barely perceptible with VT and PT, but it shows up very nicely with MT.

Best regards - Al
Parent - By 46.00 (****) Date 10-03-2012 04:46
Don't sound so good to me...........
Up Topic American Welding Society Services / Certifications / D1.1 Weave width restriction??

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