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Up Topic American Welding Society Services / Technical Standards & Publications / D1.5 question regarding change of electrode classification
- - By jwright650 (*****) Date 06-12-2014 20:20
Background:
AWS D1.5
Process used was GMAW
ER70S-3 using 85/15 was qualified with a PQR and then a WPS was subsequently written.

Few months/years pass and fabricator keeps chasing porosity and worm tracks. Call to the electrode mfg and the mfg's rep suggests changing to an ER70S-6...whalla, all of the porosity and worm tracks disappear.

Yesterday:
I visit the fabricator at their request to perform a mini spot check audit to look over their procedures and paperwork ahead of an AISC audit and discover the change in electrode classification. I suggest that they switch back to the ER70S-3 until they have a chance to qualify the ER70S-6. In the meantime they mention this suggestion to someone else(another CWI) and they basically said I was full of it. This is D1.5 and not D1.1, so I'm wondering if their comment wasn't thought through and was just a shot from the hip?

So what is the opinion of the forum on this matter of using a PQR that was qualified with ER70S-3 but using ER70S-6 on production bridge work? All of this is confusing to the fabricator and they just want to do what is correct by D1.5.
Parent - - By welderbrent (*****) Date 06-12-2014 23:48
Alas, no copy of D1.5 here with me John.  And not enough experience in it to 'shoot from the hip'.

Question: is the suffix an essential variable in D1.5?  I know D1.5 goes beyond D1.1 in many regards as do D1.8 Demand Critical weld requirements. 

If I am looking at the listings in D1.1 correctly then it isn't an issue there.  But I know the others require many different parameters when it comes to procedures. 

Wish I could help but I'm codeless (clueless) right now.

He Is In Control, Have a Great Day,  Brent
Parent - - By jwright650 (*****) Date 06-13-2014 00:17
Hi Brent,
I agree that D1.1 doesn't seem to care about a change in classification for GMAW electrodes(greyed out), unlike FCAW or SAW.(see Table 4.5)

D1.5 lists changes to the classification as an essential variable. I realize that people swap S-3 and S-6 GMAW electrode all of the time without much thought.
(I don't have a copy of D1.5 here at home to point to the reference)
Parent - By welderbrent (*****) Date 06-13-2014 01:56
John, I think you and I are on the same page.  But, to make sure and to make a couple of my contentions clear to others let me explain:

Here would be my question, Most of the tables in Clauses 3 & 4 'X' several portions of the 'classification'.  ER70S-X, ER70S-XXX, etc for GMAW.

It is also important to keep 'classification' and 'AWS Specification' clear and separate.  Table 4.5 says a 'classification' not covered in 'specification' A5.18 or A5.28.

From these two examples I would then ask if the suffix is not a critical component to the value of the essential variable for an electrode classification?  So, changing from ER70S-3 to ER70S-6 is not a change that requires an additional PQR/WPS because it is still covered under the same specification? Not even for CVN.  Did you change the or an ESSENTIAL part of the classification when you changed the suffix?  The important part of the list in Table 4.5 is in the wording: "Change to an electrode or flux-electrode classification not covered in: AWS A5.18 or A5.28" (which are AWS Specifications).

NOTE: we are talking about GMAW so Table 4.5 (3) does not apply.  We are talking about a change based upon (4).  If we were talking about FCAW there would be a difference in the direction of my questions. 

Now, changing other facets of the classification do mean a change requiring testing.  The classification must be applicable to the process in use.  The purpose is to show the fabricator knows what he is doing and not just grabbing numbers out of a hat.  And one must note the 'exceptions' listed for suffixes in Table 3.1.

Bottom line: how much of the 'classification' is under consideration when saying that a change in classification requires a change in WPS which would mean a new PQR where one is in use instead of prequalification?  Considering the process in use of course.

Then, to transfer more directly to your OP: D1.8 defers back to D1.1 for most essential variables but adds two items.  Manufacturer and heat input.  Still no inclusion of suffixes that may change.  Still don't have access to D1.5 so can't get any closer than that.

He Is In Control, Have a Great Day,  Brent
Parent - By js55 (*****) Date 06-20-2014 12:29
John,
I'm weighing in a little late on this but here is my take. I see no point in re-qualifying from 3 to 6 unless it is a Code requirement or you are experiencing issues as described. Both will achieve the minimum strength levels required. As for CVN's you may experience variances. You may not. The variances may well be within the scatter band. There are some old papers out there from TWI related to SAW that shows that if you 'cleanse' oxygen too much it can actually be detrimental to impact toughness. And it is almost impossible to predict because of the interrelationships of other alloying variances. Thats why we test. I don't have anything on GMAW but were I to guess, and it is just a guess, I would say the phenomena would be consistent.
I usually limit the choices in solids between 2 and 6 due to welder preference pertaining to viscosity more than anything. I have little concern for a variance in mechanicals (6 will be stronger due to manganese).
Although  I will say this. S-3 has an odd history in that it was originally invented because Lincoln kept missing heats in the melt and with their influence were able to create a new classification of cheaper wire so they wouldn't have to re-melt. Nothing wrong with this as such. But I just choose not to use it. I will pay a little more for the triple deox of 2 or the wetting of 6.
- - By 803056 (*****) Date 06-14-2014 21:42
I'm talking through my hat here. I don't have D1.5 handy, but I know CVN is usually a requirement on many bridge projects. If one refers to D1.1, Table 4.6 for CVN, classification is an essential variable. That being the case, a change from one suffix to another is grounds to require another PQR.

I'll check with D1.5 when I get a chance.

Al
Parent - By jwright650 (*****) Date 06-16-2014 10:46
Thanks guys for the replies......I'm just trying to confirm that I wasn't being too far off in my suggestion to a client.
Parent - - By jwright650 (*****) Date 06-19-2014 13:05
Al ...(and others who have a copy of D1.5:2010 and the time to reply),

When you get a chance(I know we are super busy during this time of year, so when you get a chance), look at
Clause 5.5.1 in AWS D1.5:2010 with me.

Clause 5.5.1 WPS Requirements for Consumables.
See Table 5.1 for the WPS qualification requirements for consumables.

and

Table 5.1 WPS Requirements for Consumables
(first item in the list)....
Each AWS Filler metal classification (follow across to column with GMAW and there is an "X" indicating it is applicable).

Would you agree or disagree that a change from ER70S-3 to ER70S-6 requires a requalification?
Parent - - By 803056 (*****) Date 06-19-2014 14:42
My short answer is yes. A change in classification (for SMAW, GMAW, or FCAW) affects the level of deoxidizer contained in the weld deposit. When the deoxidizer is not utilized for that purpose, it becomes an alloying constituent and changes the deposit chemistry. Aluminum is one of several deoxidizers used. Aluminum in excess of minute amount (and other deoxidizers) can have a negative affect on toughness.

Best regards - Al
Parent - - By aevald (*****) Date 06-19-2014 15:49
Hello Al, I'm jumping in the middle here a bit, but aren't the deoxidizers scavenging unwanted elements and bringing them to the surface of the weld pool to be off-gassed or simply become part of the surface covering, as opposed to being distributed fully in the weld metal deposit and thus changing it's metallurgical make-up or the toughness factor? Just wanting to know and understand more fully. Best regards, Allan
Parent - - By 803056 (*****) Date 06-19-2014 16:41
Deoxidizers interact chemically with the oxygen that is in solution in the molten weld pool to prevent the formation of CO. Gases such as oxygen, nitrogen, hydrogen, and CO have high solubility in molten iron/steel. The carbon has a high affinity for the oxygen in solution and forms CO which manifests itself as porosity when the solubility limits of gases are greatly reduced as the liquid weld metal solidifies.

The addition of deoxidizers such as manganese, aluminum, and silicon, all of which have higher affinity for oxygen than does the carbon, results in the formation of solid oxides such as manganese oxide, silicon oxide, or aluminum oxide which is preferred over gaseous CO.

Best regards - Al
Parent - - By aevald (*****) Date 06-19-2014 17:16
Thank you Al, that's exactly why I asked the question. I now have a very definitive answer and a different take on the form and function of this. Best regards, Allan
Parent - By 803056 (*****) Date 06-19-2014 21:54
Glad to help.
Al
Parent - By jwright650 (*****) Date 06-20-2014 11:04
Good stuff Al, thanks for sharing :cool:
Parent - By jwright650 (*****) Date 06-20-2014 11:14
Actually Al, these bridge beams do have CVN testing as a requirement when they were ordered from the mill. However, CVNs from the welds themselves were not required, as far as I could tell from the contract docs.
Thanks for bringing that up...I had let that slip by me.
Up Topic American Welding Society Services / Technical Standards & Publications / D1.5 question regarding change of electrode classification

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