Good Day, Members
4.9.3.3 states, "The convex surface of the bend test specimen shall be visually examined for surface discontinuities". If the action of bending either causes or reveals a discontinuity on the side (not part of the convex surface) of the test coupon, in the weld area, and not mitigating from the edge. What criteria is used? This happens rarely but it has happened.
Ironmac15,
WELCOME TO THE AWS WELDING FORUM!!
I only have my D1.1:2008 in front of me at the moment and it references Clause 4.8.3.3 for your question but quotes the same.
The coupons should have been examined visually before cutting the coupons combined with an examination after cutting the coupons of the weld root and indications of incomplete fusion. From there you will bend it and the convex surface of the bend is the only concern per the criteria list
ed in 4.8.3.3 (or 4.9.3.3 if reference is according to another edition).
The only other time the side would be examined is dependant upon the other requirements of your testing, ie does it specify macro-etch, RT, or UT? Macro-etching would bring those indications to light BEFORE bending and reveal any discontinuities and rather they were rejectable.
If the test were properly observed during welding, the coupon visually inspected before bending, and all other things being fulfilled, the edge is not a consideration after the coupon is bent.
Have a Great Day, Brent
Brent has said it nicely.
When we come to the bends it is important to dicipline ourselves to consider only the areas the code requires us to look at.
Other areas are viewed prior to the guided bends.
Having said that. The exception I partake in is the following:
4.8.3.3 (3) Says the following:
" 1/4" the maximum corner crack,
except when that corner crack results from visible slag
inclusion or other fusion type discontinuity, then the
1/8" maximum shall apply"
My personal interpretation of this is to view the radius of the prepared coupon and the sides of the bend coupon, as often porosity or even lack of fusion at the beveled edge can be seen as the source of crack propagation.
Corner cracks that appear to initiate outside of the convex surface but travel into that convex surface are always suspecet in my opinion. (I take a conservative perspective on this issue)
I can think of no other case where it is aproprate to inspect outside of the convex surface.... Even if something appears on the inside radius that was not visible during the initial visual inspections... It's out of bounds .... Mentors I trust advised me on this particular topic years ago, when I was tempted to view things my own way.. (Thanks Al)
I totally agree Lawrence. And I should have explained further but as he had stated it did not come from the corner I left it alone. But, it should be examined pretty close to make sure it did not come from the corner and if something does appear in the corner then your quote applies completely.
Now, I also feel that when something in the side opens up, it appears that there must have been some lack of fusion going on. BUT, we can't really look at it unless we determine it originated from the corner.
Have a Great Day, Brent
ironmac15
Was your coupon put in the jig so the the weld is completely within the bent section?
I ask only becasue sometimes mine would shift and a small part might end up not completely in the bend, and if this were your case had it been positioned 100% it then might have been within the criteria to evaluate it.
just a thought.
I totally agree. Just to clarify, if a open discontinuity starts on the convex surface and wraps around to the side (corner crack) the inspector is to measure the entire crack....even down the side...not just the length of the crack on the convex surface. In other words, as soon as there is a corner crack the side is no longer "out of bounds" for that crack. Would you agree?
Pipes, the corner crack is only measured across the convex surface. Not down the side.
PWC
No kidding? Wow...I'm glad I asked. I thought you measured the entire length of the crack.
By 803056 
Date 12-08-2012 18:35
Edited 12-09-2012 16:24
D1.1 is no different than any other welding standard. It delineates the minimum requirements that must be met to be compliant with the standard.
"If the defect is small enough to be ground out, the bent sample is good enough." That's a quote from a mechanical contractor that was qualifying his welders in-house. The individual quoted was the shop foreman/janitor that was also assigned the task of qualifying the contractor's new hires.
In my thirty years of testing welders and welding procedures the case noted above was the most egregious, but I cannot say it was the only case of “how not to qualify welders” I have encountered. I wasbeen on one project where the contractor was testing welders in the position he called "Chinese vertical". The test coupon was positioned at 45 degrees and the welder welded in the overhead position. This one position qualified the welder for all positions for AWS D1.1 as well as ASME Section IX according to the contractor.
In other cases I have seen instances where the company handed the welder several sets of coupons. The welder was told to weld them and hand in the best one for evaluation. There was no mention of what process should be used, what position the coupons were to be welded in, or what electrode should be used.
Is this an argument that welders should only be tested by third party laboratories? No, I have seen where the laboratories used the wrong bend diameter (one of the labs was an ATF and the other an accredited lab). I've seen welder qualifications issued by AWS that didn't list whether the welder took the test with or without backing and the certification made no distinction. There are enough rocks to be thrown and the numbers of glass houses are plentiful enough to last until all of us are dead and buried.
The bottom line is that each of us should strive to test welders within the requirements of the applicable welding standard. That isn't to say the codes are never ambiguous or murky with regards to the tests administered or the proper evaluations but it is what we must work with. However, the welding standards delineates the minimum requirements that must be met. The tests described in the AWS D1 structural welding codes are the mandatory tests that must be passed. Not all the standard tests meet the conditions of prequalification, but they are the tests the structural welding committee has agreed to use. The contractor is free to administer supplemental (additional) tests where increased degrees of difficulty can be imposed; the acceptance criteria can be made more stringent, or other obstacles can be imposed as determined necessary by the contractor. If the contractor wants the welder to take the test hanging upside down with one arm tied behind his back, so be it. The contractor can also dictate what tools can be used to clean and prepare the joint when the welding standard doesn't include any restrictions. It is fitting that the contractor be afforded the lattitude when the welder is tested, after all, it is the contractor that is responsible for the quality of the work produced by the weld, not the third party testing laboratory.
In my humble opinion it would be prudent for the Engineer to review the WPS used for welder performance qualification as well as the actual welder performance test reports before allowing an individual to weld on a project. There is no reason that responsibility cannot be delegated to an individual that has the appropriate training and experience to perform those tasks if the Engineer is not comfortable reviewing the welding documentation . Since the structural welding codes have assigned the responsibility for testing welders and assigning properly qualified welders to perform the production welding to the contractor, it would be prudent to include a requirement that the review and approval of all welding documents by the Engineer is mandatory in the project specification. If the Engineer then identifies a deficiency, corrective measures can be taken before the project gets underway. Better yet, test each welder on the job site using the equipment that will be used on the job site. The test can be a simple T-Fillet Break test. A test consisting of one weld pass in the position required for production. Break the weld and examine it. What could be simpler and more cost effective?
I know, I know, the contractor’s will cry, wring their hands together while whining that it will drive up the cost of the work and could possibly delay delivery or completion. I say that is a small price to pay in consideration of the cost of cutting out bad welds to correct deficiencies caused by the use of unqualified welders.
Best regards - Al
