Low hydrogen Moisture

Date 05-15-2009 15:57

http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=61032

I posted some pictures of an experiement in this thread...lots of good info also posted within this thread...but the pics are worth a thousand words.

By Lawrence (*****)

Date 05-15-2009 16:04

Better pack a lunch before you engage that thread

By jwright650 (*****)

Date 05-15-2009 16:33

At least pop some popcorn and get 20oz Pepsi;)

By MRWeldSoCal (***)

Date 06-25-2013 16:07

Holy Crap it tooke me two days to get through all that information on those threads

By jwright650 (*****)

Date 06-25-2013 18:56

By G.S.Crisi (****)

Date 05-18-2009 20:57

Lincoln (www.lincolnelectric.com) and ESAB (www.esab.com) explain exactly how to storage and take care of E 7018 low hydrogen electrodes, and the reasons for it. Apart from searching information on their sites, you can give them a phone call and ask for a printed catalog on covered electrodes. There's plenty of useful information in their catalogs.
Giovanni S. Crisi
Sao Paulo - Brazil

By 522029

Date 05-18-2009 21:19

Just so everyone knows, there are lots of FREE catalogs and informative booklets at the Lincoln website posted by Mr. Crisi.
I believe you are limited to ten publications per request. Some are mailed to you and some are downloadable in pdf format.

Also, Lincoln does not blast you with unwanted junk mail. They only send what you request.

Hope this helps
Griff

By 803056

Date 05-21-2009 15:24 Edited 05-23-2009 20:16

I tried my best not to jump in on this thread, but at long last I couldn't resist!

I completed a project several months back where the welders did not have a hot box on the project. I was informed by the project supervisor of the problem when he called and asked the question, "Al, you insisted on the welders storing their E309-15 electrodes in the hot box. Does the same requirement apply to their E7018?"

I responded that the same requirement applies and the details are spelled out in the WPS that covers the welding of structural steel. He pulled out the WPS and said, "You're right, its listed as a requirement in the footnotes addressing electrode storage. You better come out here and check what they are doing."

So, I showed up the next morning to qualify the welder. I bumped into him on the ground and asked him what electrode he wanted to use for the test. The question was asked so I had a reason to check the electrodes without being too obvious. He opened the side door of the truck and said he was going to use 1/8 diameter rod, so I grabbed a hand full of 1/8 E7018 and told him I would carry them up to the working deck. He grabbed the rest of his tools and off we go!

I asked him to grab a couple of pieces of backing bar. He looked at me and said, "I thought I was going to do a fillet weld test?"

I replied, "Yes, you are, but first we're going to test the electrodes you were using yesterday."

He gave me a funny look, but did what I asked. He welded a short bead on the backing and we quenched it in water, dried it, knocked off the slag and submerged it in the baby oil. Many of you already know what the expected outcome was; it gave off a cloud of tiny bubbles of hydrogen gas. The welder's eyes nearly popped out of his head and his lower jaw nearly left a dent in his chest!

"But, those weren't the rods we used yesterday! We used the rods in the hot box over there!" he said rather excitedly.

I was already informed that they had bought a hot box to the site in the late afternoon when the project supervisor made them read the WPS. So, I told the welder to repeat the process using one of the rods from the hot box knowing full well what the outcome would be, but still I had to appear to be somewhat empathic with his plight.

Think about it; electrodes that have been exposed to the humid environment for several days are placed into a holding oven with a rubber seal around the top. The oven is plugged in and the cover closed and secured tight. The rods are heated to 250 degrees F overnight, but there is no place for the moisture to escape! The moisture is still contained by the closed oven! To top it off, the temperature required to "rebake" the electrodes is 600 degrees F, not 250. Add even if the rods were baked at 600 degrees, I find it hard to believe all the moisture could be driven from the flux because of the chemical bonding that may have taken place between the flux covering and the moisture present. That's another thread for another day. Our good friend and welding expert Stephan can help us with that one!

Back to the story. We repeated the experiment with the rods withdrawn from the hot box and still the bubbles of hydrogen evolved freely when the sample was submerged in the baby oil. Now panic was setting in. Even the project supervisor was shocked that the rods stored overnight in the hot box gave off so much hydrogen.

"Where did you learn this stuff? I've been welding or around welding my entire career and I've never seen anything like this before!" he said.

I told him I would expect a Millwright to know this type of stuff. What can I say, I have to break everyone's xalls once in a while. He doesn't get mad, he gets even (when he gets a chance). That's when he tagged me with the nickname - "Welding Nazi". Payback!

So, now the contractor gets really nervous and says he's going out to buy some fresh wire. I said, "Where are you going to buy rod on a Saturday?"

He said he was going to go to "Home Depot" if the welding supplier isn't open.

I told the project supervisor the wire from "Home Depot" won't pass either. He asked why not. They are not in sealed cans was my response, "They come in cardboard boxes and that isn't sufficient to exclude moisture over long periods of time." I said.

Sure enough, the welding supplier was closed and they found some 1/8 diameter electrodes at "Home Depot". To top it off, the plastic wrapper was torn in one corner. I gave the project supervisor a wink and said "Let's see how this works out."

The welder welded the piece of backing bar, dipped it in water, wiped it dry, and knocked off the slag. Then he gently placed it in the baby oil and waited. I don't think he took a breath for fresh air during the entire time!

Slowly at first and then faster and faster, pop, pop, pop, again hundreds and then thousands of little hydrogen bubbles began to appear!

"Now what?" asked the welding foreman.

Anyway, I thought you might get a kick out of that little story.

Best regards - Al

By DaveBoyer (*****)

Date 05-22-2009 03:52

"You can always tell a welder, but you can't tell him much"

That is why You have to SHOW them.

By 803056

Date 05-22-2009 12:51

So true, so true, but once they see it, they never forget it.

Happy Memorial Day!

Best regards - Al

By JTMcC

Date 05-22-2009 16:56 Edited 05-22-2009 17:31

I don't work very often in the structural world, maybe once every couple of years. But when we do we keep our consumables properly while people working around us sometimes do, but many times don't.
So feel free to correct me if I'm wrong but wouldn't it be just this simple to correct: put language in the contract documents that say something to the effect: "consumable storage and handling not in conformance with XYZ code/standard/etc will result in rejection of all welds made with those consumables solely at the contractors expense"??? Put all schedule damage on him as well, plus the replacement cost of any structural member that has to be replaced.

I would think that would make contractors sit up and take notice, and conform. Maybe I'm missing something here though. And of course you'd have to have engineering (or someone in a position to include the spec) on board but that should be easy?
I would like it as it would level the playing field a bit when I'm quoting work against others who save by cutting these corners that we're not willing to cut.

In our piping world, contractors wouldn't even think of playing games with comsumables or a procedure, but inspection wouldn't batt an eye at calling every weld a cut out either.

JTMcC.

edit: I realize the statement would be redundant when the docs already say welding will be done "in accordance with XYZ code", but I still think it might grab the attention of contractors who are cheating on handling consumables.

By 803056

Date 05-22-2009 21:09

The language is in the code for the most part, but the problem is now and always has been that some contractors are gamblers at heart. They figure if they get away with "it" the majority of the time, they're ahead of the game. Getting caught is a cost of doing business. It doesn't matter if "it" is having the right permits, certifications, electrode storage, etc., the fines levied, the cost of rework, etc. are simply costs of doing business.

I had one contractor say to me, "Al, at any one time I have 10 jobs going. The chances are that you will only inspect one of them. I can afford you."

At that point, the general contractor and the owner looked at each other and the owner told the erector his services were no longer needed.

Then you hit the sore spot in making reference to the engineer. On most projects the inspector has little authority regarding who is permitted to weld, what gets repaired or replaced, etc. Ultimately the inspector reports his observations to the EOR and it is the EOR that has to have the nerve to insist the work be corrected, the welders be properly certified, etc.

The inspector can do little more than continue to log the nonconformances, voice his concerns and do the job he/she is being paid to perform. As long as the EOR signs off on the nonconforming work, the building officials will sit there fat, dumb, and happy. Fortunately, the majority of the engineers I work with do support me in getting bad work corrected. However, there is always a minority that were in the lower tier of the graduating class and don't ever "get it" and they never will. When I encounter those types of engineers I simply move on to better things and make sure my name isn't associated with them.

Rarely will an individual inspector find support by leap frogging over the EOR. In one case I had the "State Building Official" ask me, "How many buildings actually fail Al?"

When I started naming the buildings that did collapse he said, "Al, that was a rhetorical question. I don't need a response."

I don't want to sound cynical. Most contractors strive to do their level best, most engineers insist on quality work, and there are many fine inspectors acting as the engineer's eyes on the job site, each one trying to ensure the owner gets what he pays for. Unfortunately it is the minority that leave a lasting impression with everyone.

Best regards - Al

By welderbrent (*****)

Date 05-23-2009 00:27 Edited 05-23-2009 00:32

Al has hit it with great accuracy. Firstpass, I'm glad you are asking for information. I think the first posters have adequately covered that.

Why buy rod ovens, take extra time controlling rod distribution, educating the workers as to proper handling procedures, etc. when you can save all that time and money and take a vacation at the customers expense? With any luck the building won't come down until after the warantee period or some natural catastrophy extreme enough that they won't even check for improper building practices by the contractor. Just one of those 'extenuating circumstances'.

I wish we could actually insist on proper education for all welders and especially their employers. But no, it's bad enough they have to be certified and have all these WPS's and other 'worthless papers' like proof they have been welding since they were certified.

On the other hand, where do you draw the line on what people need to know to do their job? Do we teach engineers to weld and do equipment and building repairs before they can get certified as an engineer? Do we teach welders metallurgy and stresses and engineering principles before they can weld on a commercial structure?

But even without going to these extremes, there is so much that can be taught in a short time that is very needed if people really want to be "professionals" and be qualified to do their jobs.

Now days we have a bunch of shake and bake welders. Go to a trade school and...wham...bam...thank you...I'm a certified welder. I've said it a lot and proved it more than once. I can take almost any one who has been welding for a couple months and get them certified. Yes, it is that easy. They ran the plates. But were they even good welders let alone experienced professionals able to understand the principles involved to accomplish the job to code? They need to have at least the important basics of an education beyond being able to run a decent bead.

Being a professional used to involve schooling, apprenticeship, more education, practice, work, training, all under a "Master" of one's chosen Craft/Trade. You had to prove your ability to do a job right before you were given the privilege of responsibility for your own work.

Most of these people today cannot even properly name the tools and/or equipment they are using, let alone the welding processes in use. And we are 'TRUSTING' them to put up high rise buildings, dams, pressure vessels, homes, etc. And they won't even store and use 7018 rod correctly. Shame on the Building Officials, Inspectors, Employers, and Professional Welders.

Sorry I have gone on so long. I'm tired of the total lack of skill amongst my "peers". There are many who are good, concerned, educated, trained, professionals. There are many more who are not. Beginning welders should not be on critical jobs, even if they can pass a certification test. There is much more to this 'Profession' than that.

Have a Great Day, Brent

By 803056

Date 05-23-2009 11:51

Brent, you hit the nail squarely on the head. Training, learning, and experience are critical components to being a professional.

The apprenticeship programs offered by the building trades are a key component to maintaining a skilled workforce. It is unfortunate that many owners don't understand the value of hiring companies that have or participate in apprenticeship programs for young people entering the trades.

How many "Young Bucks" have we encountered in the field that have just finished a ten week welding course, bought a pickup truck and a machine and now they are "contractors". They have never seen the "code" let alone know what's between the front and back covers. I guess we should look at it as "job security". It just too bad that the owner gets hosed by getting substandard work if there isn't a qualified inspector to ride herd over the "young-uns".

I guess that's why the Navy insists on formal training and a written examination for any welder that wants to weld on Navy contracts. I just finished teaching a forty hour class for a company on the East coast. Even the welders with twenty years of experienced were amazed at what they didn't know before completing the class. The format of the examination is similar to the format of the CWI examination; a closed book section, an open book section (they use 4 Navy standards), and a hands-on section over the course of 6 hours. I do believe many of them are actually surprised at the amount of information they retain and they all have a little more strut in their stride after passing the examinations.

The bottom line is that we, as CWIs, SCWIs, and professional welders, have a responsibility to ensure the welders on the job do it right and when possible and where possible, pass on some of the knowledge we have acquired. Let's face it, none of us have learned all that we know on our own. We've all had mentors that pushed, poked, and prodded us to learn more by hands-on experience, reading, and attending seminars or school.

I've had several mentors. As a youngster, an older gentleman took time out of his work schedule on Saturday mornings to teach me the basics of welding. Then when I became an Ironworker apprentice two Journeymen became my mentors and did what they could to make me a better welder. One of them had a brother that was a Professor of Metallurgy at WPI in Worcester, MA, he would answer our many welding questions in great detail. He was a resource that we no doubt greatly abused. Then an engineer challenged me to take the CWI examinations. His remark was that if I thought I knew so much about welding, I should have no trouble passing the test. I passed and I still work with him on a regular basis. One of my clients took me under his wing and introduced me to NDT. Since their business centered around providing NDT training, he was kind enough to offer me the opportunity to attend NDT classes. That became another facet of my education. With the gentle prodding of my mentors I attended college at night. Over the course of several decades I earned college degrees that complimented what I learned by working for a living. I didn't "do it" on my own. I had plenty of help along the way.

I can only hope that I can be as generous with my time as those gentlemen were. I hope someone says, "I learned a lot working along side Al." That would be a great compliment.

We all have the opportunity and responsibility to "train the young-uns". After all someone took the time to educate us.

Happy Memorial Day and remember all those that have sacrificed so much protecting our country.

Best regards - Al

By MRWeldSoCal (***)

Date 06-25-2013 21:35

Well Al I hardly know you but damn have you bumped my education up a massive ammount. I started the same way almost. Welded in High school a bit, saw a tig welder at 300 amps and it blew my mind. I never looked back. I started welding for a career immediately after highschool, I am 28 now. I had an amazing teacher here in Fullerton CA. He really inspired me to take it all to the next level. He was the kind of person who could answer and teach you with easy, MUCH LIKE YOU. I check this forum every day at work to read and look for your answers cause it makes making sense easier. If that makes sense haha. I was also challenged to become a CWI by my teacher, but also cause I wanted to understand the science of welding more. I got my degree in Manufacturing from taking night school over the course of say 7 years. Little by little. I had help though, My teacher, and head of the department for the college took me in under his wing and began to take me on ride alongs, train me in how to read a code book. IT has come full circle back to me. Im actually going to back to school now to get another degree because I want more and more. I have wanted to be a teacher for the last 4 years or so cause I am a very good welder and have great patience and teaching skills with most welding processes. As luck would have it a spot opened up at the very school I began at 10 years ago and I start my first paid teaching semesterthis coming fall. So here is a young gun who made it, and hoping to inspire more young guns to find their passion and break the limit to their own knowledge.

Cheers!
-Jordan Maxwell

By 803056

Date 06-26-2013 12:43

Jordan;

That is great news.

You now know that acquiring knowledge is a long draw out process. You can attend the School of Hard Knocks where the lessons learned are slow and expensive in terms of time and money. I include money because many of the lessons are as a result of making a mistake and learning how to do it correctly, which often includes the cost of repairs. If not the School of Hard Knocks, there is always learning from the mistakes made by others which are recorded in books. However, even that takes time and money, but it is usually less expensive and quicker than the alternative.

No matter which route one choses, we all need mentors that are willing to share their experiences and point us in the right direction. Many people are willing to act as mentors if the person being mentored is willing to listen and learn.

Like you, I've had several mentors over the years and I am thankful they were willing to invest their time and experience in me. There are very few of us that can do it on our own. Even those individuals that self proclaim they did it on their own are full of hot air.

I hope you do as your instructors did, share your experience and education with all those students that attend your classes. Not all of them will be sponges thirsting for knowledge, but there will be plenty that will listen and learn.

Good luck - Al

By JTMcC

Date 05-23-2009 16:06

Well 803056, I guess if engineering and the owner aren't on board you're just stuck with it.
Of course if they DO get on board, they hold the hammer, and can make it right very easily.
I'm glad the majority of what we do is in areas where what you describe would mean large amounts of money changing hands, and contractors goin out of business. It makes life easier when everyone is held to the same standard. It makes it a LOT easier to quote work.

JTMcC.

By 803056

Date 05-23-2009 19:54 Edited 05-23-2009 20:29

A well written project specification can work wonders if it is enforced.

I am in a fortunate position in that regards. One of the engineers I work with usually asks for my input when developing the project specification for the section on structural steel. A few of the items we require are copies of their quality control manual, welding procedures, welder performance test records, and sample inspection reports as part of their bidding package, i.e., their bid isn't accepted without proper documentation. We typical include the statement that all rework and reinspections are at the expense of the contractor. We always require shop inspections, that is we don't exempt AISC certified fabricators from third party inspections. However, we insist that the fabricator's QC perform their inspections and file written reports as per their approved QC program before the third party inspector (that would be me) buys off on the work. Visual inspection is specified as 100% and it must be performed by the fabricator. The owner's representative/third party inspector compares their findings with the fabricator's inspection reports. If there is a major disparity, the fabricator has to have their work inspected by a different third party before the owner's representative (again, that would be me) accepts the work. We make sure the fabricator knows and understands they are responsible for their work and the owner's inspector/representative is on the job to provide quality assurance, not quality control. This ensures the fabricator implements good QC or they pay the added cost of a third party to provide those functions. That typically gets their attention very early in the project. Nothing speaks louder than the all mighty "Green Back".

One of the goals is to provide a level playing field and the other is to ensure the owner gets a quality product that meets the applicable codes. Everyone has an equal opportunity to bid the work as long as they comply with the project specifications.

I think I am straying from the original question, so I'll stop my ramblings.

We never did actually say how "LoHi" electrodes should be stored or conditioned. Sorry about that. In a nutshell, the electrodes purchased in a hermetically sealed tin (can) should be placed in an electric holding oven set at a temperature no lower than 250 degrees F. Electrodes purchased in other containers should be conditioned by baking them at a temperature between 600 and 800 degrees F for one hour before being used. The maximum exposure time for E7018 should be limited to 4 hours (out of the oven) unless moisture resisting covering (flux) is used. By the way, the oven has to stay on all the time. Electrodes exposed for time in excess of 4 hours need to be reconditioned in an oven set to 600 to 800 degrees F for one hour and they can only be reconditioned once. Electrodes exposed less than 4 hours can be reconditioned (one time only) at 250 degrees F (min) for eight hours.

I know some people will say that the cardboard box with a plastic wrapper is considered to be hermetically sealed, but my experience indicates otherwise. Play it safe, buy the rods in sealed cans. Plastic is not impermeable to moisture from what I've seen. I tend to be conservative. It works for me.

Best regards - Al

The attachment shows the results of a test performed using fresh E7018 removed from a cardboard container sealed with plastic wrap. It doesn't appear to be "low hydrogen" considering the cloud of bubbles rising from the weld bead in the photograph. Admittedly, the test wasn't done under laboratory conditions, but when tested with an electrode that has been properly stored or removed from a fresh sealed tin, this sample is not in the same league.

Attachment: HydrogenPlumeE7018fromCardboardContainerMay2008.pdf (88k)

By kipman

Date 05-24-2009 15:31

As an additional cautionary note to what Al has written, I will add that you also have to be careful with vacuum pack electrodes. If the pack is a tight bundle the vacuum is secure, but if the electrodes can move around inside the pack this means the packaging has been punctured or otherwise breached and definitely should not be used right out of the pack - they should be baked first.
Mankenberg

By 803056

Date 05-24-2009 16:15

Good point.

Al

By Paladin (***)

Date 05-26-2009 01:18 Edited 05-26-2009 01:40

803056 wrote:
"He welded a short bead on the backing and we quenched it in water, dried it, knocked off the slag and submerged it in the baby oil. Many of you already know what the expected outcome was; it gave off a cloud of tiny bubbles of hydrogen gas."

I hate to show my ignorance but here goes. Why baby oil? Will it work with other fluids? How long will it vent hydrogen? Will it vent hydrogen if cooled slowly? Where is the hydrogen coming form? Is the metal porous? Sounds like a good parlor trick to me.

I believe in following procedures when called for. I am with you there. But I have welded up stuff with 7018's that were not kept in ovens. Bet I'm not the only one. I'm wondering what the difference is in weld strength in Lo Hy and High Hy rods are?

From Lincoln at this link http://www.lincolnelectric.com/knowledge/articles/content/fillermetals.asp

(snip)
Can Hydrogen Affect Mechanical Properties?

The influence of hydrogen can be observed in mechanical testing; however, its effects on the test results are limited. A high hydrogen content in a tensile specimen can produce "fish-eyes" on the fracture surface as seen in Figure 1.

Additionally, the presence of hydrogen can reduce ductility (as expressed by elongation and reduction in area). Hydrogen, however, does not typically influence the impact toughness, ultimate tensile strength or yield strength results. It is only in severe cases that it can influence the ultimate tensile strength.

Since low hydrogen SMAW electrodes like E7018 are also required to have a minimum specified level of Charpy V-notch (CVN) impact energy, low hydrogen is sometimes equated with a minimum CVN level. This has led some people to specify low hydrogen when the real desire is for notch toughness. The better approach is to specify notch toughness requirements since there is no automatic link between low diffusible hydrogen content in the weld and CVN values. Actually, some deposits with high hydrogen levels can deliver relatively high levels of notch toughness. For example, the E6010 classification (non-low hydrogen, 30-50 mL/100g) has a minimum CVN requirement of 20 ft-lbs at minus 20°F.
(snip)

A little ductility may be lost. We hope to make welds that don't fracture so fish-eyes should not be much of a big deal.
So in the real word, what is the practical difference in 7018's stored properly and 7018's that are not as well kept?

By 803056

Date 05-26-2009 11:16

I'm short on time this morning, so I have to keep the answer short and to the point.

Hydrogen can promote cracking under the proper conditions, i.e., brittle microstructures, rapid cooling and high restraint.

Carbon equivalency is the sum effects of various alloying consituents added to iron to enhance steel's performance. As the CE increases so does the potential for hardening when cooled rapidly from austenizing temperatures, i.e., above 1330 degrees F. This can easily happen when tack welds or root passes are deposited without the benefit of preheat. The rapid cooling (quenching) and high CE promotes the formation of martensite, a high hardness, low ductility microstructure, that is associated with delayed hydrogen cracking.

Even low carbon steels can experience delayed hydrogen cracking under the proper circumstances. I've had samples welded (intentionally) with LoHi electrodes that were not stored properly show numerous small cracks even though there were no obvious discontinuities that would produce the type of cracks observed. Then a second sample, welded with good LoHi electrodes, bent with no problems. Coincidence or luck of the draw?

Sorry for the short version, but I have to leave the office to meet a client.

I hope my short description helps.

Best regards - Al

By Superflux (****)

Date 05-26-2009 16:55

803056,

From my reading and involvement with Catastrophies, most disasters seem to be the result of the compounding of the effects of independent failures, independent of each other would probably not lead to collapses, explosions, etc. but the chain reaction of "insignificant" errors is what leads to seeing your facility on the evening news up in flames!

This why we as professionals, whether making the sparks or pushing the paperwork must strive to limit those flaws whenever and wherever we can.

Never seen the baby oil trick...sounds impressive...BUT !!! by quenching in water, are you not introducing H2O and H2 into the metal? seems an AIR "quench" would be a better control of the H2 variable.

not being critical, just curious.

regards, john

By Lawrence (*****)

Date 05-26-2009 17:42 Edited 05-26-2009 18:01

Many of the Hydrogen designators and controls for SMAW and FCAW electrodes came through research from inspection of catastrophic failures of buildings and bridges related to the Northridge and Loma Preata earthquakes in California. Those disasters provided evidence and data from failures of newer (relatively) buildings that were constructed in compliance with various builiding and bridge codes.. The evidence discovered was obviously compelling enough to cause regulators (AWS, FEMA, mil-spec, etc) to produce stricter controls on hydrogen in fluxes in both production of the electrodes and storage.

So Paladin's excellent question about "practical differences" between properly and improperly controlled electrodes can be answered by looking at those failures.

As far as the baby oil trick.... As long as the control electrode that has been properly stored is also water quenched, the example seems to have relevence in my opinion. Keeping in mind this is a training exercise to help people understand there is a "difference" between properly and improperly controled electrodes.

Interesting reading
http://www.mwsco.com/kb/kb_frameset.asp?ArticleID=76
http://files.aws.org/wj/2007/02/wj200702/wj0207-28.pdf
http://www.jflf.org/pdfs/papers/fabguide.pdf

By Superflux (****)

Date 05-26-2009 18:52

Thanks Lawrence, those links are great.

Baby oil. Cool!
Now, I can't wait to get home and try this out.
The unenlightened, myself included, are always in need of graphic examples to aid in understanding what the engineers have already proven.
On the other-hand...Hey it weren't for flashy info-mercials I'd never wasted my money on the "Magic Bullet"!

By JTMcC

Date 05-26-2009 19:35

Lawrence can you point me to some information on these catastrophic failures?
I know there were a lot of damaged connections but I don't believe any semi modern WSMF buildings collapsed.
I haven't heard or read of any steel bridge collapses, several elevated concrete freeways did suffer catastrophic failures though.
Any information would be helpfull.

JTMcC.

By Lawrence (*****)

Date 05-26-2009 19:56 Edited 05-26-2009 19:58

JT... Prolly I could be more clear

When a building or bridge go down even in an earthquake I tend to think of that as a catastrophic failure... Even the best designs and adherance to spec will crumble if the good Lord shakes hard enough... But when these things happen now a days.. Engineers can do analysis on everything.. Construction from various generations can be contrasted, engineering design, weldments etc. can be looked at and improvements in design and control can be found. So did the bridges and buildings catistrophically fail only because of bad welds? I dunno... But there is lots of data available about those fallen bridges and buildings and how the welds and weldments did not perform as designed and some of those reasons were tied into process control related stress risers.

After the Northridge and Loma Preata quakes just about every highway bridge in the state was reenforced, even those built just a few years before the quakes..

Here is some info that talks about the Northridge and Kobe findings.
http://authors.library.caltech.edu/5014/1/HOUes97.pdf

Just a page or two from another
http://books.google.com/books?id=Aaa5sUHmN7cC&pg=PA185&lpg=PA185&dq=weld+failures+Kobe+earthquake&source=bl&ots=76idrqz4o4&sig=RY1yS_RpFro-XBh8AGbCxXjKZuo&hl=en&ei=7EUcSrCYFIzCMbiRqZkP&sa=X&oi=book_result&ct=result&resnum=4

http://authors.library.caltech.edu/5014/1/HOUes97.pdf

I think I recall some articles in the Welding Journal too.. But right now it's just easier to google some info.

By JTMcC

Date 05-26-2009 21:10 Edited 05-26-2009 21:27

No. I think it's clear to everybody that collapse = catastrophic failure.
But I've read in several reports that no WSFM building (where the hundreds of damaged connections have been found) collapsed. Several state that no building failure, and no casualties are attributable to the damage done to welded connections.
I certainly haven't read everything in print on the Northridge weld failures but I've read all that I've come across. All have stated that in spite of individual welded and welded/bolted connection failures the buildings stood.
I don't have time to read the links you posted right now. Do they (or do you have other info) specifically state that any building or steel bridge actually collapsed due to weld failures? That was (sorta) my original question.
Most of the concrete bridges were refitted before Northridge, and they performed pretty well. Elevated freeways failed at a much higher rate than bridges.

JTMcC

OK I got a break and looked at those links, I've seen them before and I don't see where they attribute a structural collapse to the failed connections in any modern structure.
I still have never heard of a catastrophic failure in Northridge that was caused by those now world famous poor welds. I've seen a lot of statements that none occured.
So if anyone has evidence to the contrary I'd like to see it, I know quite a few people who work in bridge, foundation and building construction in the area (and have myself on a small scale) and it's a topic of interest to me.

JTMcC

By Paladin (***)

Date 05-28-2009 03:37

About that baby oil trick. Due to not enough time, and or patience, and or initiative I don't read every word of every thread or check out every link. But I did go back and to the second post of this thread and clicked on the link jwright650 provided.
http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=61032

Wow! Go there if you need something to read for an hour or two. Lot's of good information. Some of it a little too good for me. Anyway, the baby oil trick is discussed there quite a bit, if you missed it first time around.

By MRWeldSoCal (***)

Date 06-24-2013 21:23

AL-
So far away from this thread Holy Moly I have been caught up in these! im about 3/4 the way through the other one and then got side tracked to this one. Amazing detail and awesome Experiment.. My question is what happend to the job? the one you mentioned above? If all the rods were exposed and had hydrogen did they cut them out? if you are an inspector on that kinda of job or in that situation what do you do? have them cut everything out?

cheers to your insight!

-J

By 803056

Date 06-25-2013 13:39

As a matter of fact the Engineer did require the contractor to excavate all the welds made with the suspect electrodes.

The goal was to remove any questionable welds, but also the goal was to make sure the contractor didn't repeat the mistake on the remaining portions of the project. Nothing gets the contractor's attention like money flowing freely from their pocket to get their undivided attention.

The cost of repairing a weld is several times more than the cost of the initial weld. It is a lesson that no contractor likes to repeat.

Best regards - Al

By Len Andersen (***)

Date 07-06-2009 19:10

Ladies and Gentlemen:
My work in welding research is wet underwater welding and welding in damp environments. Hydrogen cracks are a factor that has been a concern of mine for thirty years with five patents addressing it. A large amount of knowledge about dry rod practice was obtained in the building of ships for the Second World War. Pursuant to "learning”, there was loss of live. I am a graduate engineer CWI. As a welder, your career can get interesting if in court your weld is the one associated with loss. At present, I am working for the New York City Department of Transportation (NYCDOT) Division of Bridges.
   Sincerely
   Len Andersen CWI
   212-839-6599
   www.lenandersen.com
Leonard Morgensen Andersen
Construction Project Manager
New York City Department of Transportation (NYCDOT)
Division of Bridges
55 Water Street – 5 th Floor WS-05-3F
New York, New York 10041
landersen@dot.nyc.gov

By jwright650 (*****)

Date 07-06-2009 19:25

So there you are...we have been patiently waiting for you.....here is a thread started by you some time ago...http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=11651;hl=