Welders ?!? (Aluminum)

murdomack

I too used to think that QA and QC was bit of a waste of time, especially when most competent welders/fabricators knew what to do anyway, when they are properly trained and time-served.

But after spending the better part of the last 10~15 years surveying boats and inspecting errors/cracks/warranty issues approx 90% are caused by manufacturing errors. Of these most of them fell into "basic procedures", ie laziness and structure being welded by uncoded welders, simply "we know what we're doing". So I've now seen the otherside of the argument.

Most of the welders/fabricators have no problem in being constantly checked and monitored, since we all must be part of a continuous education and training, otherwise we stagnant and hence become complacent. It is these welders/fabricators that cause the problems and have an extreme resistance to any form of QA. They do not feel the need to justify their 'skills' to anyone they have "been in the industry for years, can't tell me".

Ive seen the results of their work, it ain't pretty. It has costs many tens of thousands of pounds to repair. Sloppy standards leads to sloppy workmanship. I've got more photographic evidence of "sloppy workmanship" by the "you can't tell me types" than you can shake a stick at...still, i hear the same chorus of "you can't tell me"...as they get down graded from doing real structural work.

Since most of "these" welders only weld small boats, which until recently were not required to comply or weren't classed approved anyway. To weld a Class vessel, major structure, one needs a class cert, a valid one, current and clearly stating the parameters of the cert and hence their ability and compliance.

If someone has been doing their own work in a shed as such (years ago), for pleasure boats, standards didn't exist for them so they had no need to take any. As such they grew up in an environment where they are never questioned nor asked to comply with Class standards. Today it is different, things are changing, all for the good too.

Any welder/fabricator who constructs real major structure to Class, commercial standards require full Class certs. If you haven't got it/passed, you're not allowed to weld. All you can do is non-essential welding such as tabs. However, there is a loop hole in the rules. Fillet welds for most class, only requires a visual inspection, providing there is a decent QA system in the yard. As such these "I can weld you can't tell me types", are then allowed to do 'major' work by the back door, since frames, longitudinals girders etc, are all fillet welds!

LR are now trying to plug this gap. Even though no "formally" international standard exists for NDT'ing fillet welds with a set of pass/fail criteria, LR are now taking a slightly different line. Fracture testing is now being introduced for fillet welding major structure.

So the standards of compliance are changing and also those that "you can't tell me" will not be allowed anywhere near major structure, unless they can prove what they bleat.

Oh, my old mate used to work for Dubois around 15 years ago..i'll ask him, if he can remember. Which boat was it you said you can design the structure for?

 

Ad Hoc

You imply that I think that QA/QC is a waste of time. Nothing could be further from the truth. In fact, I say in my post that "I am all in favour QA".

There is no doubt in my mind that some weld inspectors are only welders who see QA/QC as an escape from the hood and spend most of their time trying to establish a reputation. The best, and the most effective inspectors, that I have met have been engaged in welding supervision and/or welder training. These guys already know what is right and wrong and use the manuals to back up their judgement. The "escapees" on the other hand use the manuals to make their judgement.

My story about the paint inspector was to show that there are people in inspection who are prepared to show how rather than to reject.

In a large industrial/shipyard setting it makes sense to have departmental set-ups but working in small units in the back of beyond, it is necessary to have hands-on from everyone to ensure that the same quality standard is adhered to.

 

Ad Hoc

I am surprised that you say that you do not do any testing on structural fillet welds. In our industry every weld is 100% visual, butt welds can be 10% or 100% Rad. depending on the service. Full penn structural steel welds are 100% UT and all fillets are 100% mpi or dye-pen in the case of alloys.

It looks like your Class certificates are worthless if, as you say above, they have left a gap whereby any Tom, Dick or Harry can do the fillets. Fillet welds are no less important than any other, in fact they are more so in cases, so this ommision reflects badly on Class's integrity. Like I said earlier, they spend too much time concentratring on the manual and not enough on the welding.

 

murdomack

The current state of affairs is that only visual inspection is required on fillet welds. It is 100% inspection, but visual only. The welder does not need to, in general, comply with any standard to weld fillet welds to be granted permission to weld structural work of fillet welds; but a surveyor may require a butt weld pass, but their discretion!

LR are the only class, that i know of so far, that are introducing their own QA for welders welding up a vessel built to LR Class. But all that happens is that the welder will take a fillet test, if passed, off they go. After that, it is back to just pure visual inspection. There is no formal acceptance criterion for fillet welds, even basic NDT as you have noted it is difficult. Because which standard and can you get 100% quantitative results?...NDT of fillet welds can give a good indication, but there is no real pass/fail as with butt welds.

Dye-pen etc all very good. Can highlight cracks, if it 'looks like' there may be one, just to confirm etc etc...but again, this is at the sole discretion of the surveyor....however, as we know...what lies beneath may not be that pretty, even if it looks good!

 

I theres some crap welders out there , nearly all non time served . Theres even more crap inspectors who have been on a 6 month course for basic welding inspection then bluff there way in to a job then start pontificating to expierienced tradesmen about the rights and wrongs of welding.

 

In our industry, structural welds are checked visually by the inspector and then he requests the ndt. There will be some form of ndt on every structural weld. Of course practically all our structural work is in steel, but we sometimes have work in other metals and it is generally dye penn that is used where MPI would apply to steel. With steel the MPI shows up any defect and unless the legs are extra long it would be hard to cover up bad welding given the electrodes (7018) are very unforgiving.

Any defects found are recorded as repairs against the welder. Our best welders are normally on the pipework but it is sometimes the case that good pipe welders fail the test for structural as they cannot do the root with the 7016's or 7018's. No welder is allowed to do structural fillet welds until he can pass the structural test.

I remember, back in the 60's, ndt people using ultra-violet lamps for crack detection on stainless steel fillets on pipe flanges. I haven't seen this used in our trade since but it showed up a crack as clear as day. I think they used red and green fluids but I can't remember exactly, maybe the rays made them appear in these colours. I'm pretty sure that there must be a modern technique that would test an aluminium fillet, albeit they may be a bit expensive and time consuming.

 

murdomack

"... I'm pretty sure that there must be a modern technique that would test an aluminium fillet.."

yes, there are plenty. But the results are never really consistent and the presence of the web often affects the results, which is why no real formal criterion exists, because it is no quantitative enough. It is good but inconsistent too.

In your industry, vast sums of money (I assume) are given to the NDT of fillet welds. These resources are generally not available tin the ally industry. If a structure is designed well, there are plenty of load paths and hence sufficient structural redundancy. If a crack begins, it is more of an inconvenience, than a major catastrophe. (Loss of life owing to a crack, is currently zero, in my industry high-speed craft, commercial).

So when put into those terms, one can understand why the resources devoted to establishing a formal internationally accepted consistent NDT fillet test for ally welds doesn't exits.

The closest that "joe bloggs" welder comes to, is if the yard he/she is employed at, has poor or little attention to QA, then its off the street do a quick weld test for yard "QA" acceptance, if looks ok, then off to a quick test, a visual examination of the fracture surface, after the fillet has been 'knock' over. This test result is shown to Class, who looks at the QA procedure, if all ok..off they go!! But even this is not always done.

In quality shipyards it is very rare this happens, as they will insist on quality welders and only allow structural welders, ie those that have passed butt down hand test, to do the structural fillets. Overhead welders will be left to do the major work. "joe blogg's" can only do minor and non-structural work.

But sloppy yards or yards which are suddenly under pressure to finish, can and do allow very inexperienced welders perform many structural welds, why, because there is no formally agreed method of testing and hence implementing a set of pass/fail criteria.

And as lumpy said above, if these yards have crappy inspectors, owing to not being time served (i've meet plenty), then the quality and sloppy standards are even worse.

Any form of QA testing is like a red flag to a bull to an "ive been in this industry for 40 years mate, can't tell me.." types. They've never been properly tested against any formal standard and made to do this consistently every couple of years. As such they are used to their own little world and no one will budge them from their myopic view of quality and welding.

 

as for that picture posted by whoosh...i wont even comment on the extremely poor structural detailing on the structure, ....shocking!

 

Yes, you're right. Coincidentally I was just googling for "fillet ndt aluminiun" when I saw your post. This is what I was looking at. I haven't read it all but table 8.1 will show you that this Norwegian Offshore spec (1997) calls for Dye-penn on aluminium fillets as well.

http://www.standard.no/PageFiles/1192/M-102.pdf

They also suggest production testing as the work progresses. This is in line with what Whoosh mentions in his last post (break tests). I'll need to speak with our QA manager and check what our spec says when I go back.

 

quite clearly ad ho, you are in denial, so I delete all the posts I can, you are not worth considering in my industry I am here to asssit people, youa r ehere to piss hard working achievers off

 

murdomack

As you noted those are for Offshore, again. Not commercial HSC ally craft. Also those reg's are only how to do the NDT in accordance with international standards, such as EN44, it is a formal QA procedure. It does not provide pass/fail criteria.

As i've noted break tests are done (#82) by good quality yards in compliance with the QA...Class generally require this as some form of minimum too. BUT, it is not 100% cast in stone, it should be, but it isn't. However, Class are slowly closing these loops holes. Also once the fillet welds have been done....unless it looks like *****, that is it. Unlike your Offshore industry which requires 100% testing there is no such requirement in the commercial HSC industry. There is no NDT testing of fillet welds at all. Because there is no Internationally accepted pass/fail for NDT of ally fillet welds.


Ive noticed that shockingly poor structural detailing picture by whoosh has gone....should have left for those to see how not to do structural detailing, fine example of what not to do.

Which boat was it at Dubois?...i was chatting to my mate yesterday who worked there around 15 years ago....give me the name and i'll check it out.

 

ok yes you are correct

 

murdomack.

Just as an example, here are 2 pages.
1) from Alcan's Ally and the Sea, great all round reference book.
2) From DNVs HSLC rules.

Both show that X-rays are never done on fillet welds. And also the welds are only visually accepted and only over certain percentage of the vessel anyway. As I said your standards are very different from those that are in my field, commercial aluminum vessels.

 

I have no knowledge of welding but I was involved in a robotic tooling development program for cutting, welding and weld inspection small (50 mm dia, 2 mm thick) pipes in nuclear reactors. The tools had to access the cut/weld location from inside the pipes. The chosen method was butt-welded TIG, I don't remember all the details but the computer-controlled weld speed was a few mm/sec and pulsed current was employed. I well remember the weld demonstration, the nicest per-grinding weld I have ever seen completed in about 2 minutes. The (French) guys who set up the welding parameters nailed it first time! Remarkably little heat transferred down the pipe, which was an exotic low-neutron capture cross section alloy including Niobium.

The program never got to the weld-inspection phase, too much political interference, but we were going to use a coombination of ultrasonics and eddy current. I always wondered why I was selected as the lead for the weld inspection tool: perhaps it was my utter lack of training or knowledge in either welding or weld inspection. Not much use to you folk but a little light relief perhaps! Thanks for the memory.

 

Terry
thanks
I remember the Hobart co was invoved?
Most on this forum can not ID with Hobart because they were swallowed by Miller, who were swallowed by Michegan Machine tool
now they have these handy man machines in the great name, probably made in China
Countries such as Fr, De, Ru, Norway USA who have nuclear power are always going to push the frontiers of welding As far as that goes nobody in this including myself understands a thing about it I guess the closest is the oil industry Mac speaks of
Some of this stuff trickes down to us mere workers