CWI or Certified Welder input needed.

[LomitaWelder]

Last Friday I took my AWS D1.1 limited thickness certification test. It didn't go to well. When the test facilitator cut my test piece into sections for bending the weld got blown apart due to a piece of slag between the backing plate and test plate. I understand that it is because the slag is nonmetallic it explodes from the cutting torch heating it up like a rock.
The facilitator was nice enough to let me come back this week and retest without recharging me.
My question is...Can I request that the test piece be cut with an abrasive blade rather than with a cutting torch?
I have looked in the D1.1 book and find nothing outlined in the qualification section that says I can or cannot use an abrasive blade rather than a cutting torch to cut out the bend segments.
Anybody know where I can find the answer to this so I can show the test facilitator so I don't look like I'm trying to get him to bend the rules. He was a good guy so I don't want to offend him or look like a know it all j*ck*ss.

[Go1lum]

If i remember right any cutting methods can be used. I have used plasma, saw, line burner, shear.

[LomitaWelder]

Go1lum do you by chance know where I can find this in writing or is the case that there is nothing specified on how the test specimen can be cut so it can be cut by any means?

[LomitaWelder]

Does anyone have an Idea where I might BEGIN to look?
Bueller?
Bueller?
Bueller?

[Go1lum]

I couldn't find anything in the code book about it. I would imagine as long as you stuck to the code and took the test specimans out of the plate i don't think it matters how you cut them.

[LomitaWelder]

Thank you Go1lum

[Dipper Welder64]

Lomitawelder

You stated it was a 3/8 test plate that had the slag inclusion, so it sounds like no matter how you cut the coupons it most likely would have failed. Instead of trying to beat the system try to spend some time correcting what could be causing the inclusion.

[LomitaWelder]

Dipper, I have no intentions of trying to beat the system. The slag was between the backing plate and the test plate. In a real world situation this would not compromise the integrity of the weld. As I understand the backing plate needs to be removed before bending the coupon. We didn't get to that point because the coupon became destroyed.

[LomitaWelder]

By the way Dipper I appreciate the positive feedback. I thought this was a forum to help each other not put each other down.

[tanglediver]

I think that will depend on the machinery available at your particular testing facility. We always cut our practice coupons on a track burner for ourselves. However, for actual testing, they always used a band saw, unless of course as is sometimes the case, the bandsaw goes down for mechanical reasons. I cut these practice pieces on the track burner.


I am in agreement with Dipper Welder64, your focus needs to be on your welding technique. The root pass is THE most important, ESPECIALLY in the coupon zones! Preheat those plates, clean absolutely everything after every pass. Don't over heat, take a 15 minute break after each few passes. Relax.

[Hammack_Welding]

I may be wrong, but it sounds to me like if you had slag inclusion between the backing plate and the coupon then you must not have burned the root out completely. The few test I took where a backing was used we were to burn the root thru into the backing plate. It sounds like you bridged the root on the two edges of the coupons thus allowing slag to fill in the middle. IF that is the case the weld would have broken even if the backing was removed. Not trying to knock you at all but it sounds like a defective weld. I think the entire intention of the test is that if it is welded properly then it would not matter what it was cut with, but without seeing it I couldn't say for sure.

[lotechman]

It sounds bogus to me. The backing bar can be washed off with a torch but it is tricky. Unless you use a washing tip it is very easy to cut into the weld metal whether there is a inclusion or not. If you had a failure while you were cutting the strips then indeed you could have had slag or cold lap. If you cut the strips with the backing bar on I would expect problems if the strips were cut too quickly or the backing bar was not tight to the test plate underside.
The best way I have seen is to set the test plate on a milling machine and machine off the backing bar then cut the strips. In the end you have to do it "his way".

[TEK]

Originally Posted by tanglediver

I am in agreement with Dipper Welder64,(and tanglediver) your focus needs to be on your welding t

X2....or 3...

In the real world, your back plate needs to be tight enough to the plate, and your root passes burned in enough, that there is NO slag inclusions at all. That will bust a UT or X-RAY every time. Even if they take the back plate off for bending purposes, it dont mean a thing. Real deal? Make it tight on fit up and dont get ANY slag inclusions. I'm no CWI but I have passed hundreds of UT and/or X-ray tests. Been there, Done that, got the scars......

[drivethruboy54]

i agree that you most likely have slag inclusions in your root. Im nto sure the order you are preparing the test, but here is how i do mine

Weld it up, have the caps inspected.

Air arc or scarf off the backing strip first. grind it down and polish it off with a flap wheel. CWI inspects it again to check for wagon wheels (slag running up both sides of the root)

Cut your test samples

If it welded properly without any slag there will be no problems with the cutting toch.

You havent said what your using to weld the test? 7018, 211, 232, 233?

[LomitaWelder]

Drivethruboy, I am using a 7018 1/8 rod vertical up and overhead.
The reason I came to the conclusion that the slag was between the the plates is because that is what the test facilitator came to the conclusion to.
I agree with the method of cutting up the coupon and will ask him if he will allow me to do it this way.

[Dipper Welder64]

Lomita in 1993 I was L.a. certified for structural steel semi auto and manual unlimited as well as light gauge. I've been in the game alot longer and ment no disrespect except I do feel just as stated by others that the plate would have failed anyway, due to slag inclusion. So you can take it for what it's worth or you can beat yourself up untill you get the picture! again it was ment to help not run you in the ground. By the way as Hammack mention about fusion to backup bar, flip it over and you can see if you have good fusion from the burn mark on backing strip.

[LomitaWelder]

Dipper my apologies. I am under alot of pressure and I took your advise wrong because it wasnt what I WANTED to hear.

[worldsgreatestwelder]

He is cutting it with a torch because it is quick offer to cut it your self as he was nice enough to retest at no charge offer to cut the coupons your self


Issue solved

Jimmy

[drivethruboy54]

like other have said TIGHT FIT. Make sure there is no gap between the edges of the base metal and your back up strip. My guess is thats what your biggest problem is. what amperage are you running? ac or dcrp?

[Dirty_d]

If your saying its due to the torch, prep the plate via grinder. It sounds to me that you had an inclusion in the root of the weld due to bad welding not the torch. I have seen many people fail tests that were due to root inclusions. On 3/8" material preheat is not needed. Prep the backer with a grinder and the face of the groove too. When the dude goes to bend your test ask if he puts a radius on the test piece. I believe he is alllowed to put a 1/8'' radius. This will prevent any stress risers leading into a crack. There are other things that can prevent welds failing that are due to set up and plate lay out.

[LomitaWelder]

I just got back from taking my test again and this time I passed on my second attempt.

The reason I failed last time is now apparent to me. After showing the facilitator the technique he told me that it was the reason for the inclusions that caused the torch to blow the weld out. The facilitator explained to me that I was "bridging" and it was trapping slag behind the weld.

I THOUGHT that if I cleaned the slag off the weld with a fine tooth comb (dental scraping off every tiny piece) I would be fine. This is not true.

The tecnique I used to pass was to weld a root pass with penetration only on the backing plate and allowing the molten pool to flow onto no more than a 16th of the test plates. Then I laid 2 stringer beads (one on each side of the root pass) to tie the test plate into the root pass and backing plate. When the backing plate came off there were no inclusions.

The facilitator explained that alot of his students seem to use bridging because they have a problem making a uniform stringer bead.

By the way, after I found the technique to fix the problem I decided not to ask for the coupons to be cut by a method other than a cutting torch but without me even asking he cut them with a band saw.

I just want to say one more time to digger sorry I accted like an a**h@le when you told me what something I didn't want to hear.

Maybe I should start to listen to my wife then?...naaaah

Also thank you to EVERYONE who gave their input.

[worldsgreatestwelder]

Congratulations.

well done

[David R]

First, congrats on passing your test. I found this in the Bible. The procedure handbook of arc welding by Lincoln. Page 11.4-5 "These edges may be flame cut or may or may not be machined."

David

[DSW]

LomitaWelder Congrats on passing your test. Thanks also for passing along what you learned and why it happened. Nice to see what real world problems can cause and how to solve them. My previous instructor was very good at telling you what you can and can not get away with, and why. Unfortunately he had a stroke and the new instructor is mostly " just play with the heat and settings and you'll figure it out". I guess it's one way to learn, but I'd prefer to skip the simple mistakes and move on to some other ones.

[gaustin]

It is my opinion that :

Slag between the backing strip and the plate is not a rejectable condition provided the root is flush with the back of the plate and all edges of the plate are fused with the weld metal.

Having the backing strip with a gap between it and the plate can cause difficulty in oxyfuel cutting period. Laminated materials are hard to cut with a torch. The layer underneath does not receive the heat from conduction and may not be to kindling temperature when the COLD oxygen hits it. Any slag compouds the problem.

Having the backing strip pulled tightly against the plates will help reduce the chances of trapping slag but the most important part is that it allows you to put the root in without getting internal undercut on the back side or bridging as you mentioned above.

When I perform certification tests for plate tests I usually remove the backing 1st, then cut the bends.

Another condition to watch for is a slight bevel on the back side either from cleaning the back with a grinder or slight bending from being sheared. In some cases this can be heard to interpret on film and raises questions on bend tests.

Here are some illustrations that are related to backing strip stand off and RT . These are from here http://weldingdata.com/slag_nonfusion.htm

The 1st three all result in a similar image on a radiograph.







The condition below that is just slag that has rolled behind the edge of the plate would not be visible on the radiograph as a "slag inclusion"





Gerald