D1.8 Wire exposure for DC welding

Date 05-14-2014 18:45

To give you a precise answer we would need to know the manufacturer and wire. The reason being is that some manufacturers such as Lincoln have performed supplemental testing for extended exposure limits in accordance with Annex E of AWS D1.8 and can provide documentation to that effect. In this case of Lincoln wires those limits can span seventy two hours up to eight weeks.
In the absence of this supplemental testing then the code minimum of seventy two hours would apply.
I would start with an internet search and or ask your filler metal supplier.

Ramon

By jwright650 (*****)

Date 05-15-2014 18:05

My question would be why purchase a 600# drum to be used on a D1.8 project?.... vs 30# or 60# rolls that can placed into an oven when welding is not taking place to limit the accumulated exposure time. Save that 600# drum for other projects where accumulated exposure is not quite as critical.

By 803056

Date 05-16-2014 02:45

Good point John.

Al

By kcd616

Date 05-17-2014 05:27

Al,
good point
600 lbs. drum
What is this project?????????????
some guys here might like the work and paycheck
Kent

By js55

Date 05-19-2014 13:06

What kind of wire?
I do not have in memory the requirements to D1.8, but if its solid wire its a who cares. Solid wire is about as low a hydrogen as you can get.

By ssbn727 (*****)

Date 05-19-2014 15:56

That depends on the dew point.

Respectfully,
Henry

By js55

Date 05-19-2014 16:15

Henry,
I2R heating ensures that dew point does not matter.

By SCOTTN

Date 05-19-2014 19:58

Rich I,

Are there any demand critical welds on the job? I don't have access to a D1.8 at my current employer, but if I remember correctly, the 72 hr exposure limit is applicable for demand critical welds.

By js55

Date 05-19-2014 20:23

But exposure limits only apply to fluxed processes and electrodes.

By SCOTTN

Date 05-19-2014 20:44

If I remember correctly, certain welds in an SLRS can be designated by the engineer as demand critical welds and they must meet even higher standards as defined in AWS D1.8.

By js55

Date 05-19-2014 20:46

Scott,
Its been so long since I've looked at D1.8. I am just going on basics. However, I would be interested if someone had a sound metallurgical argument for maintaining solid fillers in an oven.

By SCOTTN

Date 05-19-2014 20:52

It's been a while for me as well. I'm going to research some things in my library and see what I can find. I haven't had access to a D1.8 since September of last year.

By js55

Date 05-19-2014 21:05

I have the current version but I'd have to blow the dust off of it. :smile:

By Rich I Date 05-19-2014 22:19

There are several DC welds on this project along with 14 X 500 wide flange columns.

By ssbn727 (*****)

Date 05-20-2014 08:53 Edited 05-20-2014 09:00

I'm not referring to the wire filler specifically although, AWS A5.18 and A5.28 must be met @ minimum...
What I am referring to is the Dew point in the gas shielding which is definitely an important consideration when GMA Welding and is for the most part one of the least of considerations when formulating the proper "ingredients to a recipe" to use for GMAW... In fact the only time it is seriously considered prior to the actual commencement of welding operations is when the EOR specifies it...

For example: in AWS D1.3 Structural Welding Code—Sheet Steel-1. General Provisions Scope - 1.4.6.2 Shielding Media.
A gas or gas mixture used for shielding in GMAW, FCAW, when required, or GTAW, shall be of a welding grade having a dew point of –40°F (–40°C) or lower. When requested by the Engineer, the gas manufacturer shall furnish certification that the gas or gas mixture meets the procurement specification and will meet the dew point requirement.

The other consideration of moisture control is when using uncoated filler wire which will for the most part be more suspect to acquiring moisture when exposed in relatively high humidity environments also....

In emphasizing moisture control as opposed to baking the filler metal so you don't have an argument with me concerning the possibility or just the rationale for drying used GMAW wire rolls in an oven... What I'm alluding to is something like an old refrigerator with a working light bulb configured sort of like what Al describes when he stores stuff to protect from excessive humidity... :surprised:

This is from Arcelor Mittal:

"How to Control Hydrogen in Electrodes and Gases
As with low hydrogen covered electrodes, excessive hydrogen from electrodes or gases used for gas metal arc or flux cored arc welding can cause heat-affected-zone or weld-metal cracking. Hydrogen from electrodes comes from contaminants, such as drawing compounds or grease, trapped on the electrode surface.

In addition, for flux cored electrodes, hydrogen can come from any moisture retained or absorbed by the core materials. When gas metal arc or flux cored arc welding electrodes deposit weld metal containing greater than 5 ml/100 gm diffusible hydrogen, there is a possibility of cracking in welds of many alloy steels including the “T-1” steels. To avoid this possibility, the electrodes should be procured with the electrode manufacturer’s guarantee that the total diffusible hydrogen content of the deposit is not more than 5 ml/100 gm.
Shielding gases for gas metal arc or flux cored arc welding of many alloy steels including the “T-1” Steels should be welding quality low-moisture-content gases
{dew point: -40oF or lower} to minimize the possibility of heat-affected-zone and weld-metal cracking...

Summary of Rule 1
1. For shielded metal arc welding, use only low hydrogen electrodes that provide weld metal of suitable strength and toughness – and keep them dry...
2. For submerged arc welding, use only hydrogen-controlled electrodes and fluxes that provide weld metal of suitable strength and toughness...
3. For gas metal arc and flux cored arc welding, use only hydrogen-controlled electrodes and gases that provide weld metal of suitable strength and toughness..."

Well, that's it for now... This is a topic that should be discussed more often.

Respectfully,
Henry

By js55

Date 05-20-2014 12:11

Henry,
The dew point control you are talking about is a gas manufacturing quality control testing regime criteria and has nothing to do with welding conditions. The amount of available hydrogen in the gas is set by this maximum standard.
Also, the context of the OP was filler storage and that is what I was addressing. And though your point is taken and I responded, it is a sidebar. Perhaps an important one, but a sidebar nonetheless.
Where there can be an issue of hydrogen, in my experience is leaking header systems, or, poorly regulated gas storage and transfer. However, this is a violation of the dew point testing regime and has nothing to do with filler storage.

By ssbn727 (*****)

Date 05-20-2014 21:19 Edited 05-20-2014 21:43

J, did you actually read what I wrote verbatim or did you just skim through it because I already wrote what you're describing... :confused:

So this has nothing to do with the context of the OP's query? If you say no then I beg to differ with you wholeheartedly... I say that is very relevant.

"To avoid this possibility, the electrodes should be procured with the electrode manufacturer’s guarantee that the total diffusible hydrogen content of the deposit is not more than 5 ml/100 gm."

And why does Lincoln publish this in it's AWS D1.8 Seismic Supplement Welding Manual?

"Lincoln Electric filler metals for D1.8 Demand Critical welds all meet the following requirements:
AWS A5 yield, tensile, elongation and CVN requirements for classification
AISC Seismic Provision requirements of 20 ft•lbf @ -20°F.
D1.8 Annex A high/low heat input testing requirements (40 ft•lbf @ 70°F), or A5.20 optional
“-D” designator requirements, or are exempted from high/low heat input testing.
D1.8 diffusible hydrogen limits (applicable to FCAW-G, FCAW-S, GMAW, GMAW-C and SAW)
For FCAW-G and FCAW-S, D1.8 extended exposure time of at least one week when tested in
accordance with Annex E. Some products have been tested to time periods exceeding one week.
See applicable exposure test results."

Now in the 2009 version of AWS D1.8, there are some changes from the 2005 version and one of them is this subclause:

"Subclause 6.3.2 – Clarified and corrected diffusible hydrogen requirements for filler metals" I don't have that readily available so I would have to defer to someone that does.

Respectfully,
Henry

By Rich I Date 05-19-2014 22:16

ESAB R-70

By js55

Date 05-20-2014 12:13 Edited 05-20-2014 12:18

If its dual shield you have an issue.
You may wish to take a look at the new seamless wires. They are essentially hygroscopically impermeable.

By rjtinsp (*)

Date 05-20-2014 14:24

Here is the seismic product data for ESAB R-70 Ultra. For .045 and 1/16 the limit is 3 days 72 hours, and for 3/32 and 5/64 the limit is 5 days. Not much "extended use" for this wire.

http://mam.esab.com/assets/1/BDBA5CC688D14EBE822C00D265DF8E7D/doc/85827F3CCEFF43EAB9E1C2D468A72B1F/COR_1038-en_US-SeismicDataSheet-01.pdf

Ramon

By Rich I Date 05-19-2014 22:15 Edited 05-19-2014 22:21

John,
New Shop super thinks it will save him time verses the 60 lbs spools.

By js55

Date 05-20-2014 12:11

Rich,
I've used them. And it can save a great deal of time.

By SCOTTN

Date 05-20-2014 13:22

Rich I,

Page 21 of the Lincoln D1.8 Seismic Supplement Welding Manual indicates that the requirements for demand critical welds are more rigorous. Page 22 indicates the exposure limits for various Lincoln products. I have this very useful manual in my library and I have provided the link to it below. Maybe you'll find it useful as well.

http://www.lincolnelectric.com/assets/us/en/literature/c165.pdf

By js55

Date 05-20-2014 14:00

Scott,
Excellent resource. Note, there are no diffusible hydrogen requirements for solid wires. I don't know how you would do that. The hygroscopicity of the solid wire is essentially zippo. And any pre-existing hydrogen in the wire would be rendered essentially zero by manufacturing processing.

By ssbn727 (*****)

Date 05-20-2014 21:46 Edited 05-20-2014 21:49

And that isn't D1.8 2009 either because it's a manufacturers welding manual based on recommendations Lincoln makes from their interpretation of AWS D1.8...
So, could somebody please look up Subclause 6.3.2.? This subclause is supposed to clarify and show corrected diffusible hydrogen requirements for filler metals. :eek:

Respectfully,
Henry

By js55

Date 05-21-2014 13:25

Henry,
We have to remember that the concept of low hydrogen and diffusible hydrogen are intended to apply predominantly to SMAW coatings, but in general coatings and fluxes only. It is not applicable to, nor is it tested or testable for, solid wires. There is in essence no such thing as low hydrogen for solid wires. Also, the whole idea of hygroscopicity does not apply to solid wires either.
I do not have a copy of AWS A4.3 handy but I would suspect that it does not accommodate testing of solid wires since there is no point. Solid wires are hygroscopically null.

By ssbn727 (*****)

Date 05-21-2014 15:45

Hi Jeff,
When you get a chance, would you mind citing that for me?

Respectfully,
Henry

By Lawrence (*****)

Date 05-21-2014 16:14 Edited 05-21-2014 16:23

CWB W59-13
Low hydrogen — a term applied to consumables manufactured to deposit weld metal having a specified
maximum limit to the diffusible hydrogen content or to processes having inherently low diffusible
hydrogen levels.

5.2.4.5 Diffusible hydrogen designators for GMAW and GTAW filler
metals
Electrodes used in the GMAW and GTAW processes, except with shielding gases containing hydrogen,
shall be accepted as having an H4 designator without an actual test.

D1.1 2010
C-5.3.2.1 Low-Hydrogen Electrode Storage Conditions.
"... The subsequent development of semiautomatic processes, such as GMAW
and FCAW, enabled weldments to be made with similar
hydrogen levels as the Low-Hydrogen SMAW electrodes.
However, the term “low-hydrogen” was never
used for these processes and their electrodes, since it
never went through the evolutionary process of hydrogen
minimization."

By js55

Date 05-21-2014 16:35

Henry,
I understand your question but you can't site what doesn't exist. Diffusible hydrogen is a non sequitur for solid wires. If you review the applicable documents it can only be sited based upon its absence.
However:
1) Lincoln has some historical info online that talks about low hydrogen being specifically a SMAW term.
2) Solid steel is not going to absorb moisture so therefore it is hygroscopically negligible. And through processing of the wire which is a heat generating process there would be none present at manufacture. To think of solid metal as low hydrogen is nonsensical.
3) Diffusible hydrogen in base metals is generated from filler metals with fluxes and is imposed upon the base metals during high temperature diffusion. Which will eventually diffuse out of the base metal in a time/temperature/distance function. Though at room temperature diffusion can cease as diffusion paths become blocked. However, though processes such as bake outs and PWHT diffusion will continue.

Gases can carry moisture as you stated earlier so GTAW and GMAW aren't totally out of the picture as pertains to hydrogen concerns, but other than a surface phenomena related to condensation solid wires do not, and so in the context of the OP, maintaining solid wires at certain temps is useless since any surface moisture would be vaporized through radiant and I2R heating.

By 803056

Date 05-21-2014 20:47 Edited 05-21-2014 21:00

Wait a minute, back this wagon up. You say there is no moisture in solid wire? Then where does the moisture come from when I first apply the preheating torch to the steel?

Sorry, I just had to throw that in.

Regarding FCAW electrode; not all FCAW electrode are created equal. E70T-4 has the potential to produce as much diffusible hydrogen as a SMAW electrode that utilizes a rutile type flux. FCAW electrodes are available that are capable of meeting 4 ml of [H] / 100 g of weld deposit, but that is not to say all FCAW electrode do or that all FCAW electrodes can meet the requirement of 16 ml [H]/ 100 g of weld deposit.

It has been a while, but I though the semi-automatic electrode exposure limitations only applied to FCAW electrodes that were not removed from the machine and stored in a heated storage oven while not in use.

Could the limitation on exposure times for solid bare wire be associated with the possibility of the formation of oxides on the surface of the bare wire? It wasn't that many years ago when copper flash on the outside of bare wire was prohibited. Knowing how slow government agency move, could the exposure limitation be linked to the wire that didn't employ copper flash and which on occasion had a tendency to "rust" overnight? Oxides have a propensity to absorb and retain moisture. Even copper flashed bare wire can oxidize given the proper environmental conditions. The oxides may very well hold surface moisture if they are used in regions that have very humidity and where they can have a high dew point. Fresh wire, no problem. Old wire, may be a problem.

Best regards - Al

By js55

Date 05-21-2014 20:52

Al,
I was thinking of you when I referenced the moisture in the steel context.
I was not prepared to argue what is contained in D1.8 without further research.
At this time I was only arguing the conditions of solid wire in reference to the OP context.

By ssbn727 (*****)

Date 05-21-2014 21:38

Thanks Al!

I should have mentioned the copper flashing being exposed that may produce surface oxides that can pick up moisture because after all, we were talking about exposure limits - weren't we? How does the copper flashing develop surface oxides? By being exposed to moisture in high humidity environments like in the Gulf Coast...

Does this mean that the moisture content of the gas, which can effect the process is not the only way diffusible Hydrogen can contaminate the weld metal?...
Does the copper flashing become exposed to the humidity after it's used to deposit a weld?

NO... It's exposed for a certain time and eventually oxides (a chemical reaction that produces corrosion cells) form prior to welding which draw in more moisture...
Therefore creating diffusible hydrogen on the surface of the GMAW solid metal filler wire prior to the wire being consumed and coalesced with the base metal to form weld metal.
I'm done with this thread. :roll:

Respectfully,
Henry

By 803056

Date 05-21-2014 22:09 Edited 05-21-2014 22:11

Now remember, I asked the questions. That makes my comments a "maybe." I have nothing in the form of studies to back up the hypothesis.

"It helps to stir the pot once in a while."

Al

By ssbn727 (*****)

Date 05-22-2014 03:56

Of course I didn't overlook that Al... In fact, I was hoping you would chime in and noticed that you didn't give your spoon a chance to stir yet... :surprised:

If you didn't stir it up like you're known to do often enough I would start to worry about you...

So I guess I've got some searching to do with respect to finding empirical evidence to back that up which is always fun and gives me something to do that I truly enjoy participating in because along the way, I always find some interesting factoids and tidbits to ponder with. :smile:

Respectfully,
Henry

By 803056

Date 05-22-2014 11:45

No one does an Internet search like you do.

I often wonder what your secrets are when it comes to figuring out key words and phrases when you do your searches.

Keep up the good work.

Best regards - Al

By js55

Date 05-22-2014 11:58

Al,
Internet searching is indeed an art of which Henry is a master.

By jwright650 (*****)

Date 05-21-2014 10:08

>New Shop super thinks it will save him time verses the 60 lbs spools.

Rich I suppose it depends on how busy your welders are. 600# is alot of wire to burn up in 72 hours. The shop that I used to be the QC for had guys who ran 3 or four 60# rolls per day welding heavy moments, so I guess it's possible to burn up 600#'s per welder in 3 days if all they do is stay behind the shield all day and never look up.

By SCOTTN

Date 05-21-2014 11:22

Henry,

Welds used in the SLRS have a minimum CVN of 20 foot pounds at 0 degrees F. In addition, all FCAW wires to be used for demand critical welds must be able to deposit weld metal with a maximum diffusible hydrogen content of 16 milliliters per 100 grams of deposited weld metal. The code states that electrodes shall be provided in packaging that limits the electrodes' ability to absorb moisture. Once removed from the packaging, the electrode must be able to deposit weld metal with diffusible hydrogen content of 16 ml/100 g of deposited weld metal.

By ssbn727 (*****)

Date 05-21-2014 15:46

I read that also buddy... Thanks Scott. :twisted:

Respectfully,
Henry

By js55

Date 05-21-2014 16:44

This subject is very interesting on a couple of different levels. We have had numerous threads that discussed moisture and preheating of base metals and the presence of the moisture that visibly appears on the surface of the metals and have, after perhaps some banter, ended up laughing at those who thought the steel would absorb moisture and that the moisture was heated 'out of' the base metal. And yet here, our thinking seems to be channeled, in a different way when in fact we are talking about the very same type of phenomena.
The question is, can or cannot solid metal absorb moisture?
I would add one more consideration. Through the 'cold' deformation of the drawing processes of welding wires the grain size of the metal would actually be smaller than that of say an SA-105 flange or an SA-106 length of pipe and would therefore be less likely to "absorb" moisture.

By SCOTTN

Date 05-21-2014 18:18

It's my understanding that steel doesn't absorb moisture. Otherwise, there would be internal rusting which would eventually lead to structural failures. Over the years I’ve asked various welders about the purpose for preheating the steel. Most welders know why, but I can’t tell you how many times they answer with “to get the moisture out of the steel”. From my understanding, during preheating for welding, for example, steel appears to be wet when it's heated with a torch due to combustion reactions releasing CO2 and water. It condenses on the surface creating the impression of moisture rising from the steel.

By ssbn727 (*****)

Date 05-21-2014 18:46 Edited 05-21-2014 18:55

Jeff,

Now you're putting words that I didn't use and assuming that I did... So you know where that ends up... There is a difference between low hydrogen and diffusible hydrogen and there in lies the confusion.

Now I understand that solid metal doesn't absorb moisture from condensation or otherwise for crying out loud because it's part of what I used to teach... May I also remind you that I'm not referring to moisture and instead am referring to weld metal diffusible hydrogen... Big difference IMHO...

Here's an abstract of how experimental testing was performed for both FCAW and GMAW filler wires according to various methods of measurement to ISO standards:

http://link.springer.com/article/10.1007%2FBF03321392

click: "Look Inside" to read further although unfortunately, it's just a peek so the entire article cannot be read from this link unless one has access to these articles via Springer Link...

Read pages 12 & 13 in this .pdf:

http://www.nsrp.org/6-Presentations/Weld/050812_Hobart_Tubular_Wire_Division_Project_Summary.pdf

This is from the Japan Welding Engineering Society:

http://www-it.jwes.or.jp/weld_simulator/en/cal4.jsp

and this thesis that was written by a graduate student @ Lehigh University in Eastern PA:

http://preserve.lehigh.edu/cgi/viewcontent.cgi?article=1948&context=etd

There are more links but, I'm going to stop here because 3 is enough for this topic...

This is what I'm describing Jeff... Weld Metal diffusible Hydrogen.

P.S. I almost forgot about this one from Miller Electric:

http://www.millerwelds.com/resources/articles/the-hydrogen-problem

Respectfully,
Henry

By js55

Date 05-21-2014 19:30

Henry,
There is no confusion as to low hydrogen and diffusible hydrogen. Thats why I listed them both.
Second, even though I did not study the articles in their entirety a cursory examination indicates they are talking about the GMAW process and testing the weld deposit not the wire. I have already agreed that the moisture content of the gas can effect the process. It follows that weld deposits will contain diffusible hydrogen. I do not deny this.
But we are not talking about the process or weld deposits. We are talking about the wire and whether elevated temperature storage or consideration of diffusible hydrogen in the wire is necessary.
So, the wire will not contain any diffusible hydrogen and the concept of low hydrogen doesn't apply.
My point stands.

By welderbrent (*****)

Date 05-30-2014 23:33

I know I'm a little behind the loop here but thought I would throw in my two tin pennies worth anyway,

Most of the welding done on a D1.8 job is still only under the requirements of D1.1. There are only a few members with certain welds as defined in D1.8 and AISC which require additional Charpy and other characteristics which will then require a change in filler material.

Shops that I do much TPI work in use a lot of 600 lb spools of 3/32" electrode. But, when on those Demand Critical welds of certain members they pull over a unit with 60 lb spools which are easily used up within the 72 hour period, especially with two shifts working 10 hours each. When finished it goes back into more controlled storage as per code and manufacturer. (also important to note that in AZ in an enclosed shop the temps and humidity are pretty controlled in the first place)

People go overboard when ascribing D1.8 requirements to every part of a job going into a seismic zone. Not every part falls under D1.8. Protected Zones, Seismic Load Resisting Systems, etc are very defined and have limited application. This also applies to the additional welder testing for D1.8 restricted access. 90% of the welding on a job going into seismic zones will not require this testing.

For this reason, I would suggest that the decision to use larger electrode spools to save money by buying in volume and saving time changing spools is ill advised and not made with the complete information at hand. Now, if the job is large enough, and the members requiring special treatment will be time consuming enough, and the due diligence research bares out the savings of 600 lb spools, then put them on roller carts or so they have easy forklift access and change them out every 48-72 hours with one from storage or make your facility humidity stable so that it is not an issue. Read the storage specs carefully. They are not the same as 7018. It doesn't require an oven to store at 250°F.

He Is In Control, Have a Great Day, Brent

By ssbn727 (*****)

Date 05-30-2014 23:54 Edited 05-31-2014 00:13

I agree wholeheartedly Brent! The Demand Critical welds must be detailed in the construction documents/contract drawings so as to avoid any confusion once the work starts, and only the welders that are currently D1.8 qualified are allowed to weld those joints. D1.8 is very specific indeed... Quote:

"These are the specific components in a building, such as columns, beams, girders and braces, and the connections that join those components designed to resist seismic loads.
The SFRS does not typically include all the various structural elements in a building. See D1.8, clause 3.1. Demand Critical welds are defined as “welds designated by the Engineer in Contract Documents, and required to meet specific requirements of this code.” The most rigorous requirements of D1.8 are imposed upon welds designated as “Demand Critical” (DC). See D1.8, clause 3.2. The protected zone (PZ) is “that portion of a member of the SFRS... in which inelastic straining is anticipated to occur....” Special limitations apply to attachments and fabrication practices associated with this zone. See D1.8, clause 3.3.
It is important to note that D1.8 requires the Engineer to specify in contract documents the locations of members that are part of the SFRS, which welds are Demand Critical, and the portion of members that comprise the protected zone. Illustrative examples are contained in the commentary, although such examples are not prescriptive or definitive. Contract documents should contain the specific requirements applicable to a particular project. See D1.8, clause 1.2.1.

Three Kinds of Welds
When a structure is designed in accordance with the AISC Seismic Provisions, the welds on the building will fit into three categories. The applicable code depends on the characteristics of the weld, as illustrated in the following table:

TABLE 1: CODE COVERAGE FOR VARIOUS WELDS
Not Part of SFRS    Part of SFRS
Not Demand Critical   Demand Critical
   Code Coverage AWS D1.1    AWS D1.8    AWS D1.8 DC

Welds that are not on the SFRS as designated by the Engineer in contract documents are governed by D1.1, and no special requirement for seismic considerations apply. Welds on the SFRS, but not designated Demand Critical by the Engineer in contract documents, are governed by D1.8, but the additional provisions for Demand Critical welds do not apply.

Demand Critical welds (which, by definition, must be part of the SFRS), are subject to all the applicable requirements of D1.8, as well as those additional provisions that apply to Demand Critical welds. See D1.8, Commentary C-1.1."

Respectfully,
Henry

By welderbrent (*****)

Date 05-31-2014 00:22

Besides, most welders lose more time each day smoking and talking than from changing wire. I can change out a spool in less than 5 minutes, including going to get it in most cases. I don't smoke, but I think one cigarette takes longer than that. So, smoke while you change your wire. OOPPSS!! That requires the ability to multi-task, probably against the safety regs.

He Is In Control, Have a Great Day, Brent