Problem With Cracking

Date 02-22-2014 17:55

Hello Brent, that does seem a bit odd, especially for that particular wire. Now for some questions: are they using the proper stick-out? is there any pre-heat being instituted? how old is the wire and is it being properly stored to prevent moisture pickup? is the wire speed high enough that they are getting a full coverage of slag after the completion of the weld?

Now I'll elaborate a bit on my questions: with the stick-out it is critical that they are using a long enough stick-out, this provides proper preheating of the fluxes contained in the wire and allows for efficient and proper action by them on the resulting weld deposit. As to preheat, I realize that 1" is right on the cusp of what is considered for needing/requiring preheat, yet it certainly could help, especially if the ambient temperature is relatively low. With regard to wire storage, if not properly stored/kept dry it will certainly pickup moisture which can certainly present problems with the weld deposit. Depending upon manufacturing technique(I can't remember how Lincoln makes theirs) seamed wires have the least moisture resistance, lapped wires are next, and finally there is a type of wire that is essentially "seamless", these types are generally considered the most moisture resistant. As to my final statement, I have noticed that if my wire speed is on the low side for a particular voltage that I will not get complete slag coverage of the weld deposit and it will appear as if "islands" of slag are present along the length of the run of the bead with exposed areas of weld bead with no slag coverage. Sometimes this sort of condition will exhibit "worm tracks", surface only.

Brent, I realize that you likely have experience with all of these things, yet for others who might be reading maybe this can be of assistance to them. I will be interested to hear of others thoughts on this issue. Keep us posted. Good luck and best regards, Allan

By welderbrent (*****)

Date 02-22-2014 18:18

Hello Allan, good to hear from you.

For the 1/16 the book says 1". I'm going to try to get him to pull that back maybe a little more and crowd about 1 1/4".

Wire feed seems fine especially when considered with the slag coverage. It really looks great until you clean the slag off, which comes off quite nice also.

Wire spool was brand new, just arrived from supplier yesterday and was put on the machine this morning when I got there.

Pre-heat, sun had the parts to over 50° F when we started and air ambient was about 45°F but moving up quickly, should be over 65° here today. Thought about that too and was considering having them warm it BUT, we ran the root, had only a small crack about 1" long in the center of the 12" run, ground it out, reran it, no problem. Now, we have that heat in the parts. Ran the first filler pass, crack. Ground it out, only surface deep. Ran the next pass, crack. We left it so I can get pics Monday morning and call the supplier to get their technical advice and maybe get the Lincoln guys in on it as well.

I'm also going to bring my mag yoke so we can MT after grinding to make sure it isn't just filling the crack so it isn't visible anymore.

Don't worry about any pride, I'm beside myself here with this. I don't care what my personal experience as a welder and/or inspector is, I can't figure it out. I don't mind filling in any gaps if anyone has more questions. There is nothing too trivial when trying to get to the bottom of a problem. So, it isn't just for others, it always helps me to have an outside perspective ask me questions.

Have a Great Day, Brent

PS, wish we had some of your rain and snow down here. This is looking pretty bad. One of the driest winters I've seen down here.

By 46.00

Date 02-22-2014 22:20

Brent, I have a couple of thoughts but a picture would be good. Stick out as mentioned has caused me quite a few problems, it is quite a critical variable with this process. Never used NR 233 just 232 and 211. You have stated slag coverage was fine so aevald comments about slag islands, which is another thing I'm familiar with shouldn't be a problem in your case.

One thing that you stated in you post which rang a couple of bells was "and running to keep the bead as narrow and thick as possible." Have you considered the depth to width ratio and centerline cracking? I'm not sure of the terminology you use in the US but this could be a major factor.

Last couple of outside the box thoughts, and these are long shot's but I have come across them before, it's not unheard of to come across a bad batch of wire. Also you could try drying the wire slightly, we used to store our NR wires in a container with a high powered lamp to keep moisture and damp away overnight.

By welderbrent (*****)

Date 02-22-2014 23:15

Thanks Glyn,

Yes, notice post on down a little. The ratio is of concern and I believe a lowering of the voltage will assist there.

The suggestion of drying is a possibility but remember, we are in AZ and the temps have been fair and humidity low. No moisture here. But, maybe enough to be absorbed into the wire even though it was fresh. That is a good thought.

Have a Great Day, Brent

By Blaster (***)

Date 02-22-2014 19:17 Edited 02-22-2014 19:21

I have a fair bit of experience with E71T-8 wires, but only with a few roles of NR 233. In any case the only time I have seen cracking in T-8s is when a narrow groove angle is combined with high restraint... and normally with a concave weld face.

By kcd616

Date 02-22-2014 20:11

if the same roll or batch, bad wire.
love lincoln filler metal, but have got bad wire and rod from them
hope this helps
sincerely,
Kent

By welderbrent (*****)

Date 02-22-2014 22:11

Okay, I'm going to take a stab at something here:

First, thanks Kent, that is always a possibility, especially in our area where it may have sat on the suppliers shelf for who knows how long because there probably isn't a lot of call for it in our area. (knowing the shops here, who they got it from, the work normally available, etc) So even though it is a new roll to the contractor doesn't mean it is new. And, I have gotten bad supplies from many suppliers through the years. No one is exempt.

But, sounds like they may be running into an issue that could be a combination of things. Thank you all of you for responding. If the voltage is too high, though within the parameters suggested by Lincoln, would account for a wider, concave profile with too shallow of through thickness that could start the conditions leading to this cracking.

Next, while within joint configurations, the groove is pretty tight. The 1" plate at a 90° to the other member gives it a fair amount of the rigidity mentioned, restrained from moving.

So, we have a stacked deck. A restrained part due to it's thickness, with heat on the high side resulting in a slightly concave weld bead with too shallow of thickness. So when we move slightly to the side of center and it is even thinner it wants to crack as cooling/shrinking because it is not strong enough to overcome the strain.

I will see if we can remedy those conditions Monday morning and let you know what we find.

Have a Great Day, Brent

By Milton Gravitt (***)

Date 02-23-2014 00:34

Brent like you said it could be a number of things. What about how are you restraining your test plate. That could be part of the problem also. Just a thought.

M.G.

By welderbrent (*****)

Date 02-23-2014 02:10

Not a test plate. It's a support piece for a canopy. 1/2 X 12" X about 12' plates, 4 of them with one about 6" wide making a web between two like a fabricated WF. They are using the NR 233 to weld the parts together. The joint in question is for the CJP's from the base plate to the vertical parts. The base plate is 1" X about 18" X 24". The weld is cracking. They welded several with 7018 with no problems. The steel is all A-36.

I am really getting convinced it is in the welding parameters. But, due to the configuration, to answer your question, the restraint is because of the thickness of the plate compared to the other plates and then there is a 6X6X3/8 HSS welded to the other side of the 1" plate which would give it a small amount of added rigidity in the area where this weld is being made.

Have a Great Day, Brent

By kcd616

Date 02-23-2014 04:04

idea
if 7018 works good
go with 7028 and just get it done and out the door
cost is more for smaw but it is done and to code
hope this helps
sincerely,
Kent

By Dualie

Date 02-23-2014 04:17

In my exsperiance welders have a much easier time making sound acceptable welds when running the wire at the bottom end of the operating parameters. Running the T-8 wires to hot and to fast just leaves the door open for all matter of things to happen.

By welderbrent (*****)

Date 02-23-2014 13:48

Comments noted Dualie and Kent.

Dualie, it wasn't clicking until people started responding to this thread but I agree. Need to keep it down. I believe I need to look at specs on the wire as well, but I think that is why I see most guys using the NR 232 not the 233. Just enough difference in the alloy content to make it easier to use in these situations.

Thanks for the replies everyone.

Have a Great Day, Brent

By Lawrence (*****)

Date 02-24-2014 14:09 Edited 02-24-2014 14:41

I like running both Lincoln and ESAB T-8 electrode wires ! Especially out of position... Way better than T11's in my opinion.

They are designed to run better in the upper WFS range "in my opinion" But the voltage range I've found is best at the lowest value the manufacturer recommends without spatter occuring...

I've also found that a split root pass done with stringers is more effective than a wider root-pass that might have some side to side movement. Split roots take a slightly larger gap/opening sometimes, but if you can accomodate it and not be bothered with a little extra overall weld volume, it may solve your issue without any further fuss.

Edit:
The split root technique is the answer to many problems related to single bevel CJP issues.

Check Contact Tip to Work Extension? Self Shielded FCAW is pretty sensitive here... Worm tracks are the typical result of this being wrong, but maybe cracks too?.......... Still betting on split-root for a fix.

Last thoughts: with 211 and 232 most operators like to run vertical with the gun pointed downhand about 15 degrees... NR233 the same slight drag, but some operators find that closer to perpendicular works for them a little better... I said this wrong the fist time...
The Current vs WFS on 233 is much different than 211, I think due to a thinner strip that is rolled.... But if a reduction of WFS on the root can provide a slightly more narrow stringer while still giving enough punch to fuse to the backing and still comply with your WPS... This might help also.....

http://www.lincolnelectric.com/assets/global/Products/Consumable_Flux-CoredWires-Self-Shielded-Innershield-InnershieldNR-208-H/c32400.pdf

Last last.... I've also experienced NR233 to be more sensitive to arc blow and have seen it punch holes clean through base metal in very little time..... You don't mention this, but it has been an issue for me on a number of occations.

Attachment: Vert233.pdf (54k)

By jwright650 (*****)

Date 02-24-2014 21:02

>Check Contact Tip to Work Extension? Self Shielded FCAW is pretty sensitive here... Worm tracks are the typical result of this being wrong, but maybe cracks too?.......... Still betting on split-root for a fix.

I've found too fast a travel speed combined with high voltage and can contribute to worm tracks on the cap hid just under the slag.
Back at my old shop, I had suddenly noticed that worm tracks were appearing under the slag, on the cap of the bead, and after some investigation, I found some welders had turned up the voltage so they could travel faster to make up for slacking off. I suppose the faster travel speed froze the weld quicker and trapped that gas before it could totally escape to the atmosphere.

By welderbrent (*****)

Date 02-25-2014 00:06

Just for the record here John,

To the best of this old man's visual abilities it is definitely a 'crack' not worm tracks. But, wondering how much of a connection there may be?

I'm going to take my MT yoke out there tomorrow, they weren't ready for me today, and see if they go deeper than surface. Now, I know the limitations of the yoke, but these seem to disappear when grinding just slightly into the weld. So, we were going to do MT after the surface is cleaned off a few thou and see if the crack is still there just hidden by metal pushed into it during the grinding.

Forgot to take pics today since I didn't stay around.

Have a Great Day, Brent

By jwright650 (*****)

Date 02-25-2014 00:33

Just adding to Lawrence's comments on worm tracks....sorry about the confusion.

By welderbrent (*****)

Date 02-25-2014 02:13

No, that's fine John, I just wanted to make sure everyone knew what I had. Even Lawrence through it in as a '?' as to if there may be some connection.

Frankly, I think this has been a pretty helpful conversation. Lots of good input that I really appreciate. Has given me a couple of things to look at.

Working swing/grave until 3 am down in the valley of the sun worshippers, catch a couple winks, then go see what we can come up with on this topic for a job close to home before I head back down the hill again.

Have a Great Day, Brent

By welderbrent (*****)

Date 02-24-2014 18:07

Thanks Al and Lawrence, great additional info. The operating parameters will really help narrow this down. From what you two are saying, as well as confirming the direction others were headed, they definitely need to lower the voltage. I actually had the WFS down to about that range by the time I left the job the other day. Had not checked the volts to see where he was running that at the end. Kept lowering it as well but I'm pretty sure we weren't that low yet. The welder was wanting to run it at the top side of all recommended manufacturer's specs trying to make good time.

Have a Great Day, Brent

By JTMcC

Date 02-25-2014 01:36

Just my opinion but, proper 233 wire on proper structural grades will not do this.
Thousands and thousands of tons of 232 history now without cracking problems.
I'd be suspicious of the batch of wire and (less) suspicious of the batch of parent metal. And not rely on MTR's.
I've seen untold tons of 232 run at and above the upper ends of the recomended spec with nary a crack in sight, maybe other hicups but not cracks. Something is wrong here but you knew that already.

Not to sound all stupid, but how often do they replace their tips? As an old timer said years ago in a Chevron refinery (and he solved a major problem for Bechtel in doing so), "change your tip boys, twice a day if you need it or not, it's your only electrical contact in the system". That after about a half million $ in 203Ni weld repairs (and accompanying schedule hits) on a refinery addition.

By welderbrent (*****)

Date 02-25-2014 02:08

Nothing being presented as constructive comments ever sounds "stupid" JT. I appreciate your input, I know it comes from a great deal of experience.

Good point about the tips, but, they had just bought this wire and had not even been set up for 1/16" until then. Had been running .045 NR 211. So, the liner is new, the rolls are new, the tip is new, the nozzle -though not really needed since there is no gas, is new.

While I am still inclined to give it a go with lower voltage and adjusting the WFS I am becoming more convinced that it may indeed be the roll of wire. So much trouble for such a little project.

Another example though of why they have TPI on jobs. While they aren't bad guys to work with, they weren't going to treat this as it should be. Customer would have ended up with who knows what in these joints.

Have a Great Day, Brent

By Lawrence (*****)

Date 02-25-2014 12:35

I visited the Lincoln factory last summer... What a place !

They draw enough .045 ER70s-6 every day to wrap the whole planet !!!!!! Every day !

Sorry for the sideways post... :)

By Dualie

Date 02-26-2014 02:29

Agreed an amazing place, I really dug the QC lab where they were doing charpy Vnotch tests.

By Tyrone

Date 02-26-2014 12:23

I agree with the factory being an amazing place. The capacity of the weld lab is eye opening.
Another thing that was eye opening, was how they pay the workers per piece part completed. It's really fostered a cut-throat environment.
Tyrone

By Lawrence (*****)

Date 02-26-2014 13:32

Tyrone,

I observed the opposite.

The piece part model (books are written about it) has produced a workplace at Lincoln where people have very long careers. Nobody quits.

They only way to get good piece-part numbers is to work together. Everybody must work hard, nobody can be lazy (or it shows).

Lincoln makes it's own circuit boards! Right in Ohio..... Almost nobody in U.S. manufacturing does that.

If their hard work cuts the throat of the competition? It's hard to care.

By 46.00

Date 02-26-2014 21:43

What is 'Piece Part Model'?

By welderbrent (*****)

Date 02-26-2014 23:56

Model being the way they predict and calculate how much time and expenses are involved in development.

Piece part being the way they pay a team for a completed part according to the model.

Thus, the engineers and computer says it should take 'x' man hours to complete the project with 'y' amount of materials and expenses. No matter the number of people on the team they must work together to make it in under that and thus make more money per hour. Most of the time, fewer parts means less money. Sometimes there is a base line salary, other times it is 100% piece work.

It has it's pros and cons. Mostly revolving around the people on your team. Losers, lazy, poor craftsmanship, types usually won't last long. The team won't put up with it. When they have any say so. And they often do. Unions hate them. Productive people like them. That's a blanket statement but mostly true.

Have a Great Day, Brent

By 46.00

Date 02-27-2014 10:46

Thanks, we have similar set-ups over here as well.

By Tyrone

Date 02-27-2014 11:58

It might have been my impression, but the tour guide made it sound like if you weren't pushing out quality parts, the downstream peers would be all over you. The guide said it's not for everyone becase the pressure can get pretty intense. I think the "average" guy probably can't meet the pieces per shift requirement. Good for Lincoln for making it work. It must have taken them years to find the right people and establish standard hours for every part.
Lincoln makes it's own circuit boards? Wow. Would never have guessed that.
Tyrone

By js55

Date 02-27-2014 14:04

I've seen the Lincoln plant as well. What impressed me more than anything was the shear size of it. I've also been to Appleton WI, Florence SC, and Newton NC. They were all impressive in their own way.