Electrode storage

Date 04-14-2010 04:30

My experience is that the 50-pound and 10-pound holding ovens do not form a seal sufficient to exclude moisture from the surrounding air.

Warm air is less dense than cold air. There are fewer molecules of gas per cubic foot in warm air than there is in cold air. As the oven warms from a cold ambient temperature to a higher temperature the air expands to become less dense. Any excess air simply escapes the holding oven to maintain equilibrium with the atmospheric conditions outside the oven. If the air is not free to expand and escape, it will build up pressure much like a pressure cooker.

When power to the oven is interrupted for any reason it cools to ambient temperature. The air in the oven cools and becomes denser as the gas molecules become more closely packed. As the air becomes cool, it creates a vacuum inside the holding oven. The vacuum draws moisture-laden air into the holding oven to maintain equilibrium with the atmospheric pressure outside the oven. By drawing the moisture-laden air into the oven, the electrodes are exposed to the same (or nearly the same) amount of moisture as the surrounding environment. This is very noticeable in the winter. I make it a practice to open the cover of the 50-pound ovens about a half hour after the beginning of the shift. If the ovens were turned off overnight, the entrained moisture is evaporated from the electrode coverings and condenses on the inside of the cold cover. You can see the collectged moisture. "Do not pass go, do not collect $200.00, go directly to jail." At that point the rods are destroyed and discarded.

Best regards - Al

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

Date 04-14-2010 20:25

Al is right. Rod ovens (at least the usual ones you find in welding material shops) aren't 100% air tight. They'll draw some of the external air in when they cool down.
Now, why discard the electrodes? They can be restored by heating them according to the manufacturer's instructions that are usually printed in the box.
Giovanni S. Crisi
Sao Paulo - Brazil

By 803056

Date 04-14-2010 21:16

Hello Giovanni;

You are correct. If the shop has an electrode oven that will attain the required temperature, they can be rebaked the electrodes as long as the electrodes didn't get wet.

Therein lies the rub. Few shops have ovens that get hot enough to rebake the electrodes per AWS D1.1 requirements or the manufacturer's recommendations. Per AWS D1.1 the low hydrogen electrodes meeting the requirements of AWS A5.1 (E7018 type electrodes) have to be baked at temperatures between 500 and 800 degrees F. Electrodes that meet AWS A5.5 (E7018-X and those low hydrogen electrodes with tensile strengths greater than 70ksi) have to be baked at temperatures between 600 and 800 degrees F. As I mentioned, few shops have that capability. They definitely lack the capability to rebake the electrodes in the field on all but the largest of projects.
If they are working to an ASME construction code, well we remember what the letters in ASME stand for.
Military welding standards can be even more stringent than AWS D1.1.
AWS D1.5 has requirements similar to D1.1, but there are some differences with regards to the temperature. If they have exceeded the exposure limits, they have to be redried at 450 degrees F. If the container isn’t hermetically sealed, they have to be rebaked at 800 degrees F.

I am paraphrasing the requirements, so it would be prudent to read the requirements if working to one of these codes.

Best regards - Al

By Superflux (****)

Date 04-15-2010 01:51

Giovanni and Al,

Thanks for the Chem 132 refresher on gas properties and specifically diffusion. As mentioned, our 250# oven is not capable of rebake temps (450F max). Inside were 7018, 9018-B3, 9018-B9 and E309-16. Yes, this a B31.1 job. The moisture vent bung hole on the door probably would not meet the definition of "hermetically sealed".
I suggested they ship them off to an upcoming "Corn Squeezer" (Ethanol Plant) back east. But, they were tossed in the scrap metal bin along with other undocumented filler metals.

I was far more concerned with the open 50# box of 3/32" E6010 that was in the rod room! I coulda gotten a serious spanking from the powers that be over that!

By 803056

Date 04-15-2010 03:00

Covered electrodes that do not have to meet the requirements for low hydrogen covering do not have to be stored in ovens at elevated temperature. The high temperature will damage the flux covering. Electrodes such as E6010, E6011, E6013, E7014, E7024, etc. (those whose last digit is something other than 8), should be stored in a clean dry place. Some moisture in the covering is necessary to bind the covering to the wire core. The moisture disassociates to form atomic hydrogen in the arc, which produces a penetrating arc. There are circumstances where the increased penetration is desirable.

Best regards - Al

By ssbn727 (*****)

Date 04-15-2010 04:47

Hi Superflux,

Not to be judgmental or start an argument, but if anything like this happens to anyone again or for the first time, another alternative to tossing the electrodes in the trash would be to contact the closest career & technical center, union training center, or community college, and ask them to come to the site and pick them up so that the students could use them for practice instead... The company could even write it off as a tax deductible donation to an educational institution! ;)

This way the filler metal is put to good use after all! ;) Just a another thought on what to do with the electrodes. ;)

Respectfully,
Henry

By joe pirie (***)

Date 04-15-2010 05:14

That would work provided they keep it seperated from the good rod used to take qualification tests.
I know at Ua school in los angeles the students put all the unused rod back in the oven including that which
fell on the floor had soda spilled on etc. whenever I test there i always go to the weld supply and buy a small can of
lincoln excaliber or chemetron Atomic arc. The school buys the cheapest series of 7018 they can find. Believe me
theres a real big difference between lincoln 70 series and excalibur. Nothing like a little porosity from old rod
to ruin your day. Joe

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

Date 04-16-2010 00:27

Henry,
a question that has nothing to do with rod ovens. I've often seen in this Forum the terms: community college, vocational high school, technical school.
Not living in the USA I don't know the difference among them. Since you've used one of those terms, could you explain it to me? Thankyou.
Giovanni S. Crisi

By ssbn727 (*****)

Date 04-17-2010 04:06

Hi Giovanni!

(1) Community Colleges: A two year Associates Degree school which also offers both credit and non-credit courses for both post secondary and non-post-secondary students that must have at least a General Equivalency High School Diploma in order to be accepted along with being able to meet certain minimum aptitude standards which may differ from each state's own requirements. the post secondary courses lead to achieving an associates degree in the major students choose provided they take all of the required courses in order to satisfy the requirements for that specific course major, and some of the courses may not even be for example, welding related...

Some of the required courses may be required because the state education, or accreditation body requires the students to successfully complete those courses also in order to meet the minimum requirements for either the state education department, or the accreditation body to accept that the student has me thew requirements for either an Associates of Occupational Science(AOS), Associates of Applied Science(AAS), or an Associates of Specialized Technology (AST)... An AOS usually has the least minimum curriculum requirements to be met by the school, then the AST, followed by the AAS as being the Associates degree category requiring more difficult courses in the curriculum in order to meet it's requirements.

So the highest level Associates degree would be an AAS, followed by an AST, then the lowest being an AOS and usually the AAS has higher level math, English and other courses in order to meet the minimum requirements for issuance.

Now students can also enroll in courses that do not give credit hours as well as courses that do, but are taken in order to learn a skilled trade, arts and crafts kills, computers, certain languages courses, math courses, psychology, philosophy, etc. just because they are interested in them and want to know more about these skills or subjects on an introducory level, or to complete the necessary courses required in order to be eventually granted an associates degree of some type by completing what htey did not do earlier in their lives because of whatever reason, and as long as the credit they previously achieved will be accepted by the appropriate state education department or accreditation body if the school is a private school offering some, or all of the mentioned associate degree types.

Some community colleges offer courses where internships are granted to the student who achieve higher than average Grade Point Averages (GPA's), and can meet these requirements either at the start of their senior year, or after successfully completing their third semester with the minimum required GPA and have gained the confidence of their instructor that they will successfully complete such an internship. These internships offer the students real world exposure to working in their respective field of study in an entry level position so that when they complete their internship and graduate, they have an edge over the other students of what it's really like to be working in one of the many positions within their respective fields of study.

Finally some community colleges offer to the public, workforce development courses as well as specialized non-credit courses that do offer Continuing Education Units (CEU's) instead of credit hours that can be used in order ot achieve an associates degree... In other words, the CEU's do not count towards earning a degree, but do sometimes count towards maintaining a certification such as a CWI for example provided the courses have something to do related to the duties of being a CWI.

These courses may or may not lead to some sort of certification, yet they may also be designed in order to bring the student up to the level where the student would become prepared for certification... Also, some of these specialized courses are designed to meet the ever changing needs for local, or regional industries and businesses to remain diversified and competative gobally by providing courses to them so that they have a diverse, highly trained and talented pool of employees that are cross trained in various skills in order for the companies to successfully produce a wide variety of products and maintain, or achieve higher levels of quality simultaneously. So basically, that's how most community colleges operate and what they offer their respective communities in a nutshell... There's more, but if I continue to focus on community colleges, I will not cover vocational high schools or technical schools which are confusing enough to explain their differences as well as their similarities... So I'll end the explanation regarding community colleges now and move on to #2 Vocational High Schools.

(2) Vocational High Schools: I will edit later Giovanni! I'm not feeling too good today, so please bear with me, and I'll get back to you tomorrow hopefully.;)

Respectfully,
Henry

By JTMcC

Date 04-17-2010 19:00

In my state at least, the Community Colleges are partnering up with the Universities to offer 4 year degrees from the State University without the student having to move several hundred miles.
That is they take their university courses at thier local CC and can in some fields end up with a degree from a State University without having to relocate.
Works well for a lot of people, especially if they are past their late teens/early 20's and have a job, house, family, etc. Quite a few young students take advantage of it as well, say if they have a good job in thier chosen field or are saving $$ by living at home.

JTMcC.

By Joseph P. Kane (****)

Date 04-15-2010 15:12

ASME -- Always, Sometimes, Maybe, Except.

By 803056

Date 04-15-2010 15:23

You get the "Gold Star" Joe. Two more and you get extra time to play with the picture puzzles. ;)

How are you doing these days? I hope all is well.

Best regards - Al

By js55

Date 04-15-2010 17:02 Edited 04-15-2010 17:17

Correct me if I'm wrong but isn't an oven with a vent that has a place for the moisture to go better than a sealed oven in which the moisture would be retained in the oven atmosphere to condense upon the rod whenever the door is opened?
If you had a hermetically sealed oven you would defeat its purpose every time you opened the door by letting in moisture at a much faster rate (almost instantaneously) than a vent (acheiving equilibrium) and then trap it inside once the door is closed and have it there to condense in the event of a power failure.
Just some random thoughts. :)

By 803056

Date 04-15-2010 18:08

That's the idea and it works while the oven is in operation. The problem in this case was the oven was turned off or the power went out.

With the drop in the oven temperature, atmospheric air, with the accompaning moisture, is drawn into the oven exposing the electrodes to moisture- laden air.

The solution would entail making the ovens perfectly gas tight. It can be done, but at what cost?

Best regards - Al

By jwright650 (*****)

Date 04-15-2010 18:46 Edited 04-15-2010 18:49

I was visiting a small fabricator a while ago to help them develope a few welding procedures and develope a QC program. During the shop tour I noticed the rod oven had this neat device added where the vent was originally. I inquired about this and found that the previous owner had welded a small pipe fitting to a small piece of plate and bolted that assembly over the vent, then screwed a small thermometer into the pipe fitting essentially sealing the vent.

I was impressed by the ingenuity and the ignorance at the same moment....LOL

I told them it was a great idea, "but"... that vent was designed that way for a reason.
See, they thought it was great that they could check the rod oven temperature without having to open the door. It was one of those "can't see the forest for the trees" moments.

For those who didn't know where the vent is...here is a pic of one of ours...(old and dirty)

By eekpod

Date 04-15-2010 19:43

I dare ya to stick your finger in there!

By ziggy

Date 04-26-2010 23:59

Hi John-

Nice pics.

My understanding of the small port on the rod oven is for the purpose stated in D1.5 clause 12.6.5.5. I have not seen any other AWS code refer to the small port on the storage oven anywhere but in D1.5. But I live a pretty sheltered life so if there are any other code references to the port's purpose I would appreciate references.

Looking forward to another visit to Lynchburg VA!

Thanks John

ziggy

By jwright650 (*****)

Date 04-27-2010 11:08

ziggy,
Ha....you might be(are) right. So that fabricator with the thermometer permantly afixed through that port is a step ahead of the rest of us. They had their oven fixed that way BEFORE D1.5 even specified it(most of that paragraph is underlined)....LOL

That paragraph is new to me, thanks for sharing that!
I'm always learning something new on here. OK, that's my one new thing today...I can go back home and call it a day now...LOL

Love to have you visit Lynchburg again....let me know if you ever happen to be in town.

By js55

Date 04-15-2010 20:49

I'm still not understanding the advantage. I don't see how it matters or helps that an oven is air tight if your opening the door all of the time to access the rod. As soon as you open it you get atmospheric equilibrium and then with an air tight seal all you've done is seal in the moisture to where it can't escape. Each time you access rod you do it again. If you lose power you already have atmospheric moisture on the inside that will condense.
Now, for various detailed reasons I do believe that you will get more moisture exposure with a vented oven than a sealed oven in the event of a power failure, depending upon the time frame involved and the current temp and humidity levels, but is this difference significant. I have a tendency to think not.

By 803056

Date 04-15-2010 23:16 Edited 04-15-2010 23:18

The question is not whether it is advantageous to have a sealed oven or a vented oven. They have to be vented for the reason you point out.

The question is whether or not the holding ovens protect the electrodes once the power is interrupted. The short answer is “no.” The holding ovens the writer refers to in this post were 10 pounders. They have no seal. The 50 pounders have something that resembles a seal, but I have yet to see one that would actually seal out ambient air once they are turned off. Point of fact, I usually make sure the covers are not clamped shut when they are in operation for the reasons you pointed out, that is a sealed oven would simply contain any moisture introduced by whatever means.

I'm on you side of the fence in this discussion. My last sentence is misleading. My intent was that once the electrodes were dried (as is the case when they are removed from a fresh sealed can or once they have been rebaked, they would only be protected if the holding oven was sealed were the power to be turned off. I apologize for the poor articulation.

Best regards - Al

By Superflux (****)

Date 04-15-2010 23:52

Al,
the 6010 were not in the oven but in the cabinet in plain sight undeneath the oven. Since we have no WPS for this filler metal, it was not prudent to have them on site. The Materials manager disposed of them B4 I could make the recommendation to donate them to the local Tech School.

By 803056

Date 04-16-2010 00:15

Good call.

Al

By js55

Date 04-16-2010 12:26

Al,
I believe I understood you. Never known you to be in articulate. I just think this is a good discussion. The idea is worth exploring. I also believe there should be some room for engineering judgment in these cases as opposed to just discarding the rod.

By 803056

Date 04-16-2010 14:17 Edited 04-16-2010 15:17

AWS does not provide a lot of wiggle room. If the electrodes are not stored properly, if they are over exposed to atmospheric conditions, etc. the electrodes can be rebaked (once) provided the contractor has the necessary equipment.

There are test methods prescribed to determine the amount of moisture in the electrode covering. The tests could be employed if the electrodes have been exposed to atmospheric conditions, which is the case when the ovens are turned off for a period of time. However, I doubt few companies have the test equipment necessary to do the required tests. There may be a few larger shipyard engaged in work for the military that would have on-site testing capabilities.

The rebake option is viable and relatively cost effective if the quantity of electrodes can justify the cost of purchasing an oven for that purpose. If the contractor is working with high strength quenched and tempered steels such as ASTM A514 or A517 there are requirements for some low hydrogen electrodes to be baked at high temperature before use. Those contractors would have the proper ovens for rebaking.

ASME and API provide little direction in matters pertaining to welding, including electrode storage, drying, or rebaking. ASME and API operate under the premise that every contractor has a knowledgeable staff that has the wherewithal to make decisions on matters of design, welding, fabrication, etc. You are free to practice good or bad engineering judgment. You are on your own, good luck, cheerio!

No one likes to toss out welding electrode. That should be a last resort if there is a cost effective alternative. I like the idea of giving them to a welding school if they are still usable.

Best regards - Al

By Superflux (****)

Date 04-16-2010 23:59

Al,
Not only the 300 pounds (150#s in 9018 B3, and 9018 B9) in the oven, but another 500#s that were lacking MTR's from Lincoln were tossed. I had another 100# in my office segregated for donation to the Northern Wyoming Community College District. Shoot!!!, we have 20 "Rig Welders" that would have gladly hauled them off! and GIVEN ME 12 PACK for the priviledge.
Good thing all our Carpenter 20 is GTAW!

Sometimes the waste you see is disheartening.............

By js55

Date 04-19-2010 13:07

All I can say is WOW! :)

By north_fl_cwi (*)

Date 04-21-2010 17:06

Along with what you said, ASME also expects and will check during an audit of what your electrode storage plan is, and what your plan is to rebake or discard. And it has to be documented in your ASME QC Manual. We chose to discard rods in lieu of rebake. Much easier to track and document and prove. How do you prove how many times a rod has been rebaked? LOL.

By Superflux (****)

Date 04-22-2010 00:44

north_fl_cwi,
Excellent points! I haven't had to deal with moisture laden lo-hi in many years, but nothing is worse to run than re baked Lo-Hi. Code is THE CODE and we did the right thing by tossing the rods from the oven.

By welderette (**)

Date 04-22-2010 14:58

Always, Sometimes, Maybe, Except...That's great! However I am working on an ASME "mission", preparing for a Joint Review. Our AI reviewed our QC Manual, and the first criticism was that I had referenced D1.1 (Section 5.3.1, 5.3.2 through 5.3.2.4 and Table 5.1) in terms of the proper handling and storage etc. of Low Hydrogen electrodes.
I was informed that it "is not a good idea to reference AWS requirements in an ASME Manual." So I have been on a quest in the BPVC and B31.1 looking for an ASME equivalent,
to substitute for my poor choice. I cannot find anything,...so I must be looking in all the wrong places, even Section II Part C acknowledges AWS's specifications. Can someone point me in the right direction? Thank you, thank you.
Deb

By north_fl_cwi (*)

Date 04-22-2010 21:25

ASME Sec. II, SFA 5.1, Table A3 gives you storage conditions. Paragraphs A6.11 start to touch on what is required for lo-hy rods. You can find similar charts in other sections as well.

But what ASME is looking for in your QC manual is how "you" will document ordering, receiving, issuing, and using the rods. The AWS guideline is a pretty good start, just don't use the "AWS" reference. There is nothing that says you can't use the AWS guidelines as your guidelines without the reference.

Our manual states exactly how we receive them, issue them to the welders, track the usage, and what we do with rods once they have been out too long.

Your AI should have "sample" QC manuals and lend a hand helping you figure it out. Our AI is VERY good about helping us along with our manuals and audits.

By welderette (**)

Date 04-22-2010 23:30

Thank you for the reference, I'll surely change that. I should have looked further in the SFA 5.1 section. The AI ( whom I have not yet met ) had no issues with the manual content just didn't like AWS reference. The other changes were minor, but this one kinda surprized me. I have always thought about filler metals as based on AWS standards.
We are having our pre-review in a couple weeks, and as you might imagine, I am nervous about all of it.
So again thanks for your kind input,
Deb

By js55

Date 04-23-2010 12:13

An AWS reference in an ASME Manual is perfectly acceptable. In many instances AWS is the only organization that addresses something.
The problem however is that once you reference a document such as that you are now auditable for the whole thing. You have opened Pandora's box. If you don't comply with all of it you are in non compliance with your manual.
Most people do not want a survey team scrutinizing them to a full document such as that. I know I wouldn't.

By welderette (**)

Date 04-26-2010 13:40

js55,
now that is an idea that strikes terror into my heart! Can you be audited on the entire reference, or on the entire Code that you reference? In either case I can see
why I was told " it is not a good idea" thanks for the insight!
Deb

By js55

Date 04-26-2010 15:55

The short answer is yes, you can be audited on the entire document, but of course only for those things in your scope. For example, if you reference Section IX and don't do any brazing you will not be audited on the brazing sections in Section IX.
If you reference a document such as an AWS doc you can open yourself up for the entire document if you have a scope for that operation. For example referencing D10.10 for Local Heat treat. If you reference compliance with D10.10 and do local HT you will be responsible for compliance with all of it.
You can utilize restricting language such as stating you comply with certain sections, but its easier to just leave it out.
If you wish to reference another doc make sure you really need to do it that way.
In most cases this is not the case.
In many cases its laziness. I cannot count how many times a customer has referenced a document in their spec (gnerally its just copying and pasting) that I am supposed to comply with, and when I tell them what that would entail they often report they had no idea. The doc referenced was tossed in there to cover their azz without them realizing it had cost and delivery impact.

By MRWeldSoCal (***)

Date 07-03-2013 20:05

So Al..
How do you test electrodes to see if they are bad? bring baby oil with you everywhere you go? I mean I understand if an electrode is questionable to toss it, but if you are in a situation where no one knows do you test them yourself? toss them anyways?

By 3.2 Inspector (***)

Date 05-05-2010 06:41

How can you even think about having the electrodes in the caddies during the weekend?

3.2

By Superflux (****)

Date 05-06-2010 01:30

Well 3.2,
1) It has been done that away for a year prior to my arrival at this facility and on many other projects I've been on.
2) I'm curious as to why caddy storage is a bad idea . Electrode distribution is greatly expedited first thing in the morning by having them pre loaded. Most welders are using the same filler metal day
after day.
3) Can you direct me to ASME B31.1 where this is a code violation?
4) This power failure also affected the large bulk holding oven in which the majority of the "waste" occured.
5) Is this practice prohibited in the industry or codes you are affiliated with?

By north_fl_cwi (*)

Date 05-06-2010 12:21

I don't think you will find any specific paragraph in any code that prohibits it. But I will give you my reasoning for doing exactly what he said.

Generally, the large rod oven is the "controlled source" rods are drawn and logged from. Depending on the Code you are working by, some codes are as short as 2 hours maximum out of the oven up to I believe the most is 9 hours. #1 reason I know of is, no one monitors or logs the temperatures in the rod caddies. Also, once the electrode is originally drawn and logged from the controlled source, how do you really know if the welders are pulling the rods out of the rod caddy and not using them and then returning them to the caddy?

Basically, your current practice will most likely never present a problem. However, can you say with 100% confidence you have complete welding electrode issue control and have it properly documented?

By Superflux (****)

Date 05-07-2010 01:09

north_fl_cwi,

You make some excellent points. However, for the ensueing debate, by your comments then, rods should never be returned to the holding oven once issued since all the aforementioned practices could compromise the integrity of the electrodes.
And NO! I cannot say with 100% confidence on anything that leaves my sight. It becomes like the #1 rule like firearms. Never an empty camber until you clear it yourself.

Thank you for the input. Fortunately, I'm just a boiler monkey/field rat and gots me a MANAGER that can take the flack for all these pre-implemented/Grandfathered practices.

By north_fl_cwi (*)

Date 05-07-2010 12:30

This was brought up with an ASME audit here, and we could not come up with a good answer for the question. So, we wrote in our manual that electrodes are not to be returned to the oven once they are drawn out. Some people will say, this waste rods, my answer is, not if you plan your work out, and only issue enough to get the job done. If you are sending out 10 pounds of rods to install one 2" socket weld, then you need to revise your procedures/processes.

I think it's funny how codes are written to handle low hydrogen rods, and many test have been done in labs to prove WHY you have to handle them in the way they describe, but it is the welders in the field who think they know best, or they have any authority to do what they want when it comes to this matter. Typically, the answer when asked is, "this is how we have always done it". However, that doesn't make it right.