Fluxcore Gas-shielded Wires and the correct gas

Date 07-20-2008 18:22

I guess that where the qualification process shows its colors and worth. When no guidance is available you have to develop you own parameters.

Try looking at AWS A5.18 for some guidance on recommended shielding gases for the different FCAW classifications (for carbon steel).

Best regards - Al

By aevald

Date 07-21-2008 03:45

Hello Al, this post was mainly aimed at gas-shielded flux-cored wires as they tend to be very sensitive to different gases. Particularly if they were developed to be used with a specific type. I have run into a few of these wires that have infact included stickers on their shipping boxes which indicated that they were to be used with CO2 only, 75Ar/25CO2 only, and in some cases either of these two. As of late I have noticed that there are a few that are designed to be run with 90Ar/10CO2, and in still another instance I noticed that a few are calling out between 75-80Ar and the balance to be CO2. Metal core wires and solid core wires would obviously be capable of using a myriad of different shielding gases and transfer modes so that's why I didn't include them here. I have also been to a number of shops where the guys on the floor were oblivious to paying attention to the shielding gases when they changed from solid wire to gas-shielded flux-core. In some cases they were running a gas-shielded flux-core that was designed for 100CO2 or 75Ar/25CO2 on either 90Ar/10CO2 or 98Ar/2O2. I think you can probably guess the possible issues with these combinations. These issues are the basis for my inquiries and also to possibly hear from some of those in the know(wire manufacturers)as to why they don't include at least the shielding gas requirements in a conspicuous location on the wire reel labels. Thanks for your response. Best regards, Allan

By PhilThomas (**)

Date 07-20-2008 21:24

From the manufacturer's perspective - it is quite a daunting task to get all this information on a label....particularly with the identification requirements, warning/hazard label, country of origin label, etc. When you factor in that most FCAW wires are capable of running with more than one gas (each with its own "sweet spot" parameters) and then realize that there are a number of power supplies (pulsed, straight current, inverter, suitcase) - you wind up with a quagmire of information.

Many manufacturers have product data sheets for the wires that list many of these variables and also have technical support by phone or web to help you with your particular situation.

By aevald

Date 07-21-2008 03:55

Hello PhilThomas, I would NOT expect all of this information for a solid core wire as I understand that the parameters and modes of transfer and types of current and shielding gases could vary so widely. I would however, expect that flux-cored gas-shielded wires could at least specify the appropriate shielding gas(es) that they were designed to be run with. The internet and a phone aren't always handy for all situations. I have personally been out on field jobs in settings where flux-core gas-shielded wires were being used and if we hadn't known the requirements of a particular wire beforehand it would have been difficult to have come up with this information. In a case such as this, being able to look at the identification tag on a roll of wire would give this information immediately and not pose any sort of delay or cause mistakes. Thanks for the reply Phil, it is understood and appreciated, Allan

By PhilThomas (**)

Date 07-21-2008 14:52

Allan - in addition to my comments to Dave re: safety labeling......manufacturers also have to be very careful about not providing data that could imply a warranty that is not intended, and also not provide parameters that could potentially result in weld failure.

For example - if a label said "weld at 26.5 v in 100% CO2" and you did so on a very thick, highly restrained assembly that later fails....guess who ends up in court?

Its a fine line to walk, and there are alligators on both sides of the walkway. The onus of procedure and performance qualification (rightfully) fall squarely on the end user, not the manufacturer. I realize that this isn't a problem for a welding school perhaps, be manufacturers typically don't know where a particular material is going.

By DaveBoyer (*****)

Date 07-21-2008 02:56

   I guess Drake 181's post prompted You to start this thread. Last night I tried to look up the wire He was using only to find that Lincoln makes several different Ultracore E71T1 wires optumised for different gas shielding.

   I would rather have the acceptable gas mixtures & intended operating voltage listed on the label too, and I believe Ed Craig mentions on His website that He feels this information should be on the label as well.

I knew electric shock could kill before I was old enough to talk, let alone read or weld. I know fumes are harmfull, I know not to look into the arc with My bare eyes. I don't really care this this wire meets AWS 5.20 because I don't know what that means.

   I have rolls of aluminum MIG wire that were packaged for an industrial distributer no longer in business, they are identified with a part#, heat#, diameter and a note telling Me they conform to AWS 5.10, but no alloy designation. I would like some information I could use on the label.

By aevald

Date 07-21-2008 04:01

Hello Dave, yes his post did somewhat get me started on this line of thinking. I believe this sort of information should be more readily available, at least for the flux-cored gas-shielded wires. As you could see by PhilThomas's reply he included information that also related to other types of wires, in those instances I would agree with him with regard to the tremendous amount of information that "could" be included for the solid wires and certain other types. To throw one more variable into the mix here I would also say that the self-shielded wires should probably include a sticker that says in bold print "NOT TO BE USED WITH SHIELDING GAS!" I have seen this done on more than one occasion as well. Thanks for your input Dave, best regards, Allan

By js55

Date 07-21-2008 14:09

Allan,
If I may clarify for myself. Are you saying there is no AWS classification affixed to the wire packaging that would render a suffix designation available (such as M for Ar/CO2)? Or, are you saying the recommendation runs counter to the specification testing regime on the labelled classification number?

By aevald

Date 07-21-2008 16:29

Hello js55, generally, I believe that I am reasonably well informed about most issues and your post has just brought me to realize that in this case I am not. I didn't realize that the M designation indicated Ar/Co2 shielding. Having said that I would believe that many others are in a similar situation to myself. At the same time, all of the various different AWS designations that are included with the wires indicate the need for a legend to identify them by or a working knowledge of their meanings. I don't believe that most shop floor employees would be able to identify the meanings for all of the various prefixes and number codes. I do believe that an inclusion of allowable gases on the wire tags wouldn't be too terrible of an imposition on the manufacturers, at least where flux-cored gas-shielded wires are concerned.
To comment on your last question, no, there was no conflict regarding identifying classification numbers and once an individual does locate the specific wire description and it's list of parameters and other information they do go into such things as as-welded conditions with the different gases and do a good job of identifying the differences. Thank you for pointing out that very important bit of information to me. Best regards, Allan

By js55

Date 07-21-2008 17:08

Allan,
I didn't mean to imply I am opposed to additional information. Far from it. And I wasn't really sure I understood your question right. I think we're on the same page.
There is a legend of sorts in the appendices to the specifications.

By PhilThomas (**)

Date 07-21-2008 14:43

Dave - believe me, I would like to assume that all welders know the basics of safety. But manufacturers spending countless hours in depositions proves that either they don't or choose not to admit that they did in their pursuit of a settlement.

The fact that the aluminum wire doesn't list the alloy is proof that is DOESN'T conform to AWS lol.

We have just changed our product labeling again - based on AWS specs - which says that for wires, the warning label must be attached to the spool. It used to be sufficient to have it on the box (we use three languages no less). And...to mollify the lawyers and executives who are (rightfully) tired of hearing welders claim they weren't warned...the label attached to to spool is incredibly long and intentionally attached in such a manner that the user will have to remove it to get to the wire.

Part of the labeling difficulty is the move from masonite/plastic spools to the wire baskets we use - there is basically no good way to attach a label of any size to it. A tradeoff I guess....getting rid of the more environmentally-damaging packages for something that can be recycled.

By js55

Date 07-21-2008 15:40

When we're talking about gas mixes for carbon steel flux cored aren't there really just two? CO2 and Argon mixes. Yes, I understand we have 75/25, and the European version 80/20, and perhaps 85/15 and 90/10, though I don't know why, except if your trying to use a single wire for carbon steel and higher alloys. But thats not what we're talking about. Besides, a very brief review (emphasis on very brief) of manufacturers literature seems to segregate the wires bilaterally such as this.
So then doesn't the M suffix cover it?
Unless of course the manufacturer tests their wire with a less than optimum gas mix.

By hogan

Date 07-21-2008 16:56

I don't know if I'm missing something or read this incorrectly, but wouldn't this all be cleared up with the WPS? All my welders have a WPS for each weld attached to the dwg's. All info is stated on it. Or are you asking about a non code shop instance?

By aevald

Date 07-21-2008 20:28 Edited 07-21-2008 20:32

Hello Hogan, I certainly understand where your question could be coming from regarding using a WPS to designate parameters and gas-shielding requirements and such. However let me throw out an example for you. You have a statement on your WPS that says: Spec. No. AWS A5.20-95 and ASME SFA-5.20, Classification No. E71T-1, you are using Lincoln Outershield 71 Elite wire with 75Ar/25Co2 shielding. You run out of wire and call up your vendor to indicate that you need some more. He is out of that particular wire, but calls you back and says that he has some Lincoln Outershield 71 that he could bring you. Will he, or would you realize that this particular wire is designed for use with only 100%Co2 shielding? You might already realize the difference or he might, but how many others might not and end up using a wire that could have hard spots and risk fracture issues in certain cases? This is the scenario that I would put out there to possibly justify at least readily indicating the need for this gas-shielding information with every roll. Code shop or not, I do believe the possiblility exists for many errors and problems with some of these small nuances in descriptions and designations. Thanks for including that information with this thread, it's certainly valid and important. Best regards, Allan

By hogan

Date 07-21-2008 21:24

OK I see where your coming from now.

By 803056

Date 07-22-2008 02:33

As I stated previously, this is exactly why manufacturers need to qualify their welding procedures.

I understand the difficulty involved, but the flip side is that all too often manufacturers (including schools) purchase wire based on price and don't know what they are actually purchasing. The information is usually available on the filler metal manufacturer's web site, and yes, it entails looking up the information before making the purchasing decision. The bottom line is that the manufacturer, employer, school, who ever has a responsibility to research these issues before using any filler metal. This isn't limited to FCAW electrode, but any electrode for any process.

How many times have we inspectors found welders on the job site using FCAW electrode intended for limited thickness being used on thick moment plates that are well beyond the thickness recommended by the manufacturer? How many, besides me, have seen contractors making multipass welds without removing the slag and wire brushing between passes. When I asked him what he was doing, his reply was, "It's OK, this is a multipass electrode, you don't have to slag between passes."

I don't know where he got that idea, I was afraid to ask.

The bottom line is the information on what shielding gas is typical is usually available if we do our research before we start the job. Changing to a different electrode without checking with the manufacture is simply throwing the dice and hoping for the best. Only by qualifying the WPS will we ever know what the actual mechanical properties will be and only if we control the welding parameters will we have predictable results.

Best regards - Al

By 357max

Date 07-22-2008 15:12

Stepping back to a solid ER70S6 or 3 electrode wire; its rated tensile strength is with CO2 gas. Add Argon and mix with CO2 or O2 and the tensile strength increases, and the ductility decreases. Therefore a shielding gas becomes an essential variable. This would be the case for flux and metal cored wires.
Yes, it would be nice if electrode manufacturers would package a parameter data sheet inside each spool/coil of wire.
Question, according to D1.1, can an arc voltage sensing wire feeder be used with a constant current weld output for flux cored wires? Essential variables.

By aevald

Date 07-22-2008 20:22 Edited 07-22-2008 20:25

Hello 357max and everyone else, the original reasoning behind my post was based upon a couple of lines of thought that I had as well as many of the points that were brought forth by many of you as respondents. Additionally, many other ideas and thoughts have been included bringing up more items for consideration.
   I had been led to understand(very possibly incorrectly) that specific types of flux-cored gas-shielded wires were designed with specific formulations to react in a certain way with the use of specific shielding gases. In particular, wires designed for use specifically with Co2 had particular levels of C, Mn, Si, P, and S, when these wires are shielded with gas combinations other than 100%Co2 the levels of some of the above listed components don't have the same rate of loss through the arc that they were designed for. Meaning that the as-welded chemistry of the weld deposit is altered sufficiently that you can have detrimental metallurgical issues present that can cause weld deposits that can crack or have other less than desirable performance characteristics.
   Another point of my original post had to do with including and readily identifying shielding gas types with the label affixed to the rolls instead of just relying on the specification class number. I was referring specifically to flux-cored, gas-shielded welding electrodes. I narrowed it down to this because I believe this is an area that can be included within this process without being overly burdensome to manufacturers and also not open them up to liabilities or undue additional information. I realize that solid-core electrodes can be used with a myriad of different shielding gases and also different modes of transfer(short-circuiting, globular, spray, pulse) thus it would be overly cumbersome to try to include this information for these products. Back to the flux-cored, gas-shielded electrodes for a moment, it is very evident that incorrect shielding gas applications to "some" of these electrode types can have a catastrophic effect on the finished welds. Public perception of this isn't nearly as evident in my eyes as the public perception and knowledge that is understood when you are discussing solid-cored wires. This is my logic behind this statement: The average shop welder or fabricator can readily distinguish the difference between short-circuit transfer and spray transfer and which one is appropriate to use on light-gauge materials and heavy plate. That same welder using a flux-cored, gas-shielded wire will possibly not be able to so readily distinguish between the way that a 100%Co2 shielded only flux-cored wire runs versus that same wire when it is being used while being shielded with a 75Ar/25Co2 shielding gas. In many cases the as-welded deposit won't exhibit any discernable physical characteristics that would indicate any sort of problem. The problems might only show-up as a result of a failure in service, catastrophic or otherwise.
   I did try to research the "C" and "M" wire designators for shielding gas, this definitely wasn't as straight-forward as I would have thought. You can take a look at the following sites for some additional clarification of this topic at the following sites:
   http://www.mwsco.com/kb/articles/19990608d.htm
   http://www.twi.co.uk/content/jk86.html
   http://www.key-to-steel.com/default.aspx?ID=CheckArticle&NM=83

   I also tried to locate this in the D1.1, unfortunately my navigational skills are lacking somewhat so I didn't have any luck. For many of you others you can likely locate it readily, just not the case for me.
   Sorry for continuing to beat this one. I guess it's just something that I'm going to have to come to accept, but in the meanwhile, here's my latest rant on it. Best regards, Allan

By js55

Date 07-22-2008 21:32

Allan,
I think your concerns for catastrophic failure are way way overstated. Sure mechanical properties will vary based upon shielding gases. In this case due to differences in oxidation potential between ArCO2 and CO2. But its not an issue of whether or not properties change, its an issue of whether or not properties fall below the specified minimum in which design is based.
However, spec and code mins have to be complied with and the possibility of minor reductions below code mins do and have happened. Thus, testing is necessary. But this is far far from concerns over catastrophic failure.

By aevald

Date 07-23-2008 04:33

Hello js55, as I said, I have been led to believe there are concerns in this area. If they aren't as serious as I have been led to believe then I guess at least I'll never have to feel concerned about being anal about using the appropriate gases. Thanks for the reply. Best regards, Allan

By DaveBoyer (*****)

Date 07-22-2008 05:25

Phil, In the case of the aluminum wire, the part # if I could look it up, probably would have enabled Me to find the alloy. The problem with this wire is that it was from a company that went out of business. It does seem odd that they didn't include the alloy on the label.

When someone can win a burn case because they were served hot coffee limiting liability is hopeless.