I have what looks to be a HAZ tear on a 3/8" guided bend coupon... Don't see these defects often with Hot Rolled A36. I do hundreds of these and this defect is unique. Have done several dozen tests from this "heat" and nothing similar.
.045 E71T-1
Co2 100%
325 ipm
25.5 volts
Overhead position
Stringer Beads
500 degree interpass
No quench
Correct roll direction
It really looks to me that the tear is at least 1/16" away from the edge of the cover pass bead, well into the HAZ.
Visuals were good.. No undercut at all.
Root bend perfect
Reserve 3rd coupon was bent "face" and displayed similar defect.
Any ideas?
Lawrence
Looks Ugly for sure.
The only thing that comes to mind is the direction of rolling of the material.
Good Luck
Marshall
Same here, I've only seen this when the rolling direction of the plate is transverse to the bend direction.
Hello Lawrence, that is definitely an odd one. Obviously, two things go against the logic of this example, the direction of rolling is correct and you have done other tests using the same "heat/material" and not had similar results.
Is this an actual qualification test? or possibly is this material that has been salvaged from pieces reused from a previous practice test. Here's my logic; if a practice test had been done using this material or if beads had been run on the surface of this piece and then those beads had been ground flush to the surface and the pieces then used for this test specimen you might end up with the type of tears that I see in your photo. That's the best I could do for an explanation with the information you have provided. I will be awaiting any additional information you might have to share with the forum. Best regards, Allan
Allan,
It was a student practice test. We do have a procedure to recycle for retests because I can't afford to chuck that much A36. But they are of course "supposed to" use the unwelded ends rather than beveling out the weld that got looked out... With 60 students scampering around it's possible that the second test was prepared improperly. I did ask but he "said" it was a fresh piece..
Usually when other welds are present they elongate differently when bent and it's visible on the surface inspection..
(how we catch cheaters fixing root passes eh Allan?)
I think I'll polish and etch the sample tomorrow... That should tell me one way or another if there are other beads that were blended down present outside the weld area.
Hello Lawrence, I would definitely agree with the polish and etch approach, that would certainly tell whether those indications were possibly the result of any previous welds. I also know about materials preservation, we operate on donated scrap at our school so we try very hard to "recycle" as much material as possible whenever we can. Best regards, Allan
I do alot of begging for stainless.
But I'm not going to let my Dean know you operate on scrap... Oh Hell no. :)
BTW Allan... We have a new college president.. Dr. Tom Eckert... He prefers to be called just "Tom." The guy came from Washington, where he was a president of one of your community colleges... Are you familliar with the guy? I have another meeting with him at the end of the month about a possible grant/expansion project... Any hints would be appreciated :)
Hello Lawrence, off the top of my head the name doesn't ring a bell. I would be interested to know which college he hails from, knowing that, I can likely give you a bit of intel. There are 34 community/vocational/technical colleges in Washington state, but not all of them have welding programs. I might just Google his name and see where he comes from. Hope everything is going well for you folks, we're facing some serious state budget issues that will likely impact us pretty heavily this year. Best regards, Allan
I've seen something like that one time before. I am not saying this is what it is, but:
The material was continuous casting, hot rolled then coiled.
The tear came from to low of a temperature during the coiling process. It was determined that the particular segment in question had cooled to much by the time it got to the coiling operation. If this is the case, there should be more of it in the stock you have left.
Suggest some Shearwave to investigate that possibility.
How wide was the cap on that? I've seen this a few times with a wide cap.
It was 3/8 plate with a 45 degree included angle and a 1/4 inch root opening
The cover was three stringers. Very typical. No extra passes to cover undercut.
So not a wide cap.
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