Dirty? Wire

[Lewis]

Hello,

I'm a quality engineer in a factory trying to help out some of our welders who are complaining about dirty MIG wire. We use a copper coated 120 S type. You can wipe it with an acetone soaked rag about 20 times until it finally comes clean, leave it sit a few minutes, wipe it again & the rag is as black as the first wipe. We are thinking it might be an oxide re-forming on the wire. The manufacturer doesn't seem to know what it could be. Any ideas?

[sn0border88]

Are you wiping before or after it goes through the rollers/liner?

An oxide wont wipe off with acetone, its grease, oil or airborne particles of some kind.

[Supe]

Who is manufacturing the wire? Have you checked the spools for residual magnetism? Where/how is the wired stored and packaged?

[Lewis]

It comes from Midalloy. It is stored here in a temperature controlled clean/dry cabinet. It comes to us packaged in heat shrink plastic. The wipe results I spoke of were from wire samples right off the spool before even being hooked to the feeder/rollers/liner etc.

Checked for residual magnetism? - Not yet but we probably could. Would that leave black residue on the wire?

[transit]

Copper, black. I’m thinking copper -sulfur or iron sulfer contamination. Any sulfur compounds being used, airborne hydrogen sulfate gas? Rotten egg smell?

[jsfab]

Lewis: Note, that Lincoln Electric specifically mentions somewhere on the Lincoln website, they DISCOURAGE the use of any lubes, clip-on wipes, etc. on their wires. The reason being they have already included the correct lubes neccessary for the wire to run thru the liner. Not sure what brand you are using, but if you are wiping wires straight out of the package, I'm sure you are just getting the same lube everybody else is using, I can probably run out back and rub a couple of my own wires with a white cloth, and get the same black residue. BTW, no complaints here.

Unless you are using some off-brand, third-world wire, that uses bunker oil as a lubricant and corrosion inhibitor, I suspect your problems lie elsewhere. Maybe the people holding the guns, need a little more education???? I can dimly remember, a period of my life, many years ago, when I worked in a production shop, certain guys would always blame problems on the wire, the gas, the machines, the phase of the moon, tidal currents, etc. etc.

If you are really having problems, don't ever feel shy about calling the wire manufacturer's tech line. I have dealt with all the majors over the years .... ESAB, Hobart, Lincoln, Postalloy, Stoody, Rankin, etc. etc. They KNOW, believe me. And DON'T assume, just because a lady is on the line, she's a secretary or receptionist or something,,,,,,, I learn't that real quick a couple times.

I would also suspect, a company big enough to have a Quality Control Engineer, is also big enough, and buying enough, if there are problems not able to be solved over the phone, the vendor would be more than happy to send out a rep, to help you solve the problems.

[Hass]

what are they saying the dirty mig wire is doing?

porosity? not feeding properly?

[Lewis]

Porosity is the main issue. We are addressing many of the other issues you all pointed to but this black residue is one I just can't answer at the moment since I'm not sure what it is. The supplier's weld engineer/rep is willing to visit and help us figure it out and they are also willing to provide super clean wire sealed in argon canisters at a price. I just figured this stuff was too common and simple for someone not to know what is was. Thank you all for the advice.

[lars66]

Originally Posted by Lewis

Porosity is the main issue. We are addressing many of the other issues you all pointed to but this black residue is one I just can't answer at the moment since I'm not sure what it is. The supplier's weld engineer/rep is willing to visit and help us figure it out and they are also willing to provide super clean wire sealed in argon canisters at a price. I just figured this stuff was too common and simple for someone not to know what is was. Thank you all for the advice.

I have a roll of Midalloy ER80s-d2 that just come in the other day. I was very disappointed that I didn't get my favorite brand of wire so I threw it in a feeder and tried the wire out. All I can say right now untill I use more is I might have a new favorite brand of wire. Anyhow after reading this I removed the allready open package of wire this morning to wipe some down with acetone, there is just enough of a black smudge on a white rag to be able to see it.

[TxDoc]

Just throwing this out from the Lincoln Electric site on common causes of porosity:

http://www.lincolnelectric.com/knowl...ntent/gmaw.asp

Common Problems and Remedies for GMAW
Reprinted with permission from the September/October, 1997 issue of Practical Welding Today magazine, copyright 1997 by The Croydon Group, Ltd., Rockford, IL

In much the same way that the automatic transmission has simplified the process of driving, Gas Metal Arc Welding (GMAW) has simplified the process of welding. Of all welding methods, GMAW is said to be one of the easiest to learn and perform. The main reason is because the power source does virtually all the work as it adjusts welding parameters to handle differing conditions; much like the sophisticated electronics of an automatic transmission.

Because less skill is required, many operators are able to GMA weld at an acceptable level with limited training. These same operators run into trouble, however, when they begin creating inferior welds and are unable to diagnose and correct their own problems. The guidelines listed below will help even inexperienced operators create high quality welds as well as offering tips for those who have been using the GMAW process for a number of years.

Most common welding problems fall into four categories: I. Weld porosity,
II. Improper weld bead profile, III. Lack of fusion, and IV. Faulty wire delivery related to equipment set-up and maintenance.

I. Weld Metal Porosity
Porosity Problem #1: Improper Surface Conditions
The most common cause of weld porosity is an improper surface condition of the metal. For example, oil, rust, paint or grease on the base metal may prevent proper weld penetration and hence lead to porosity. Welding processes that generate a slag such as Shielded Metal Arc Welding (SMAW) or Flux-Cored Arc Welding (FCAW) tend to tolerate surface contaminates better than GMAW since components found within the slag help to clean the metal’s surface. In GMAW, the only contamination protection is provided by the elements which are alloyed into the wire.


Remedies
To control porosity, use a deoxidizer within the wire such as silicon, manganese or trace amounts of aluminum, zirconium or titanium. Wire chemistry can be determined by referring to the American Welding Society (AWS) wire classification system.

Test the various types of wire available to find the right chemistry for a given application. To start, try the most common wire type, ER70S-3 (Lincoln L50) which contains 0.9-1.4 percent manganese and 0.45-0.75 percent silicon. If porosity is still present in the finished weld, increase the amount of silicon and manganese found in the wire by switching to an ER70S-4 (Lincoln L54) or an ER70S-6 which has the highest levels of silicon (0.8 -1.15 percent) and manganese (1.4-1.8 percent). Some operators prefer to use a triple deoxidizer such as
ER70S-2 (Lincoln L52) which contains aluminum, zirconium or titanium in addition to the silicon and manganese.

In addition to changing the wire, further prevent porosity by cleaning the surface of the metal with a grinder or chemical solvents (such as a degreaser.) A word of caution though if using solvents, be certain not to use a chlorinated degreaser such as trichlorethylene near the welding arc -- the fume may react with the arc and produce toxic gases.

Porosity Problem #2: Gas Coverage
The second leading cause of porosity in welds is a problem with the shielding gas coverage. The GMAW process relies on the shielding gas to physically protect the weld puddle from the air and to act as an arc stabilizer. If the shielding gas is disturbed, there is a potential that air could contaminate the weld puddle and lead to porosity.

Remedies
Shielding gas flow varies depending on wire size, amperage, transfer mode and wind speed. Typical gas flow should be approximately 30-40 cubic feet per hour. Using a flow meter, check that the shielding gas flow is set properly. There are a variety of flow meters on the market today ranging from simple dial gauges to ball flows all the way up to sophisticated, computerized models. Some operators mistakenly think that a pressure regulator is all that is needed, but the pressure meter will not set flow.

A pure carbon dioxide shielding gas requires the use of special flow meters designed specifically for carbon dioxide. These special flow meters are not affected by the frosting that may occur as the carbon dioxide changes from liquid form to a gas.

If high winds are blowing the shielding gas away from the puddle, it may be necessary to erect wind screens. According to the AWS Structural Welding Code, it is advisable not to GMA weld when wind speeds are greater than 5 mph. Indoors, ventilation systems may hamper gas coverage. In this case, redirect air flow away from the puddle. If fume extraction is necessary, use equipment designed specifically for this purpose such as MAGNUM™ Extraction Guns from Lincoln Electric -- they will remove the fume, but not disturb the shielding gas.

A turbulent flow of gas as it exits the gun may also lead to porosity problems. Ideally, the gas will lay over the weld puddle much like a blanket. Turbulent gas flow can be caused by too high a flow, an excessive amount of spatter inside the gun nozzle, or spatter build-up in the gas diffuser.

Other possible causes of insufficient gas flow may be damaged guns, cables, gas lines, hoses or loose gas fittings. These damaged accessories may create what is referred to as a “venturi effect” where air is sucked in through these openings and flow is reduced.

Lastly, welding with a drag or backhand technique can lead to gas coverage problems. Try to weld with a push or forehand technique which lays the gas blanket out ahead of the arc and lets the gas settle into the joint.

Porosity Problem#3: Base Metal Properties
Another cause of weld porosity may be attributed simply to the chemistry of the base metal. For instance, the base metal may be extremely high in sulfur content.

Remedy
Unfortunately, if the problem with porosity lies within the base metal properties, there is not much that can be done. The best solution is to use a different grade of steel or switch to a slag-generating welding process.

[transit]

120 s-what. How about trying another brand?

[Grandi]

Lewis,

Can you get me more info on the wire? Is it the Esab 120 SpoolArc? What is the application the wire is being used for? I might have a solution to your problem.

Thanks,

Grandi

[Lewis]

Unfortunately its a specialized composition that we use and its not made in the US. I'd love to tell you the application but I can't since its considered proprietary.

[lars66]

So what do you do blindfold the wire mfg. rep when he comes to help you out? Hard to help some one that won't share information.

[Grandi]

Good one man. Got a chuckle out of me.

[Grandi]

I do a bunch of business with the Military. That's why I ask. I have some knowledge when I comes to these things and was just trying to help out. I may have seen this before, that's all.

Grandi

[pistolnoon]

TXDoc certainly hit on a few points, the wire is exposed to open air?their may not be any body here that can help you if you are using a specialized formulation of wire, but frequently I recommend welders go into http://www.netwelding.com for a good explaination of pressure/flow causing turbulence at 48+ cfh and above, problems with porosity and factories that have had success changing the old ball type flow meter, also manifold systems and the particular difficulty measuring true flow.
The best resolution would be for the rep to bring wire batch of known composition and batch No.,fresh tank of sheilding gas to one of your machines and track it backwards from their.

[Boostinjdm]

Originally Posted by jsfab

The reason being they have already included the correct lubes neccessary for the wire to run thru the liner.

I remember an ammo manufacturer claim the same thing about it's .22 rounds, but all the "lube" did was jam stuff up. Not saying that's the problem, just throwing it out there. I've welded with some pretty nasty wire in the past that didn't cause any problems. The wire was so rusty once that it wouldn't fit through an oversized tip. I had more feed problems than porosity.

[i4sillypwr]

By porosity I'm assuming you are talking about very visible porosity on the surface of the weld. If it's something smaller and only visible on an xray feel free to ignore the rest of this post.

I doubt it's the wire personally. I would lean more towards user error. Do your best welders seem to have any problems or just some of the guys? I've worked in a factory setting and actually ran into something like this where another robot operator was blaming porosity problems on our cheap wire(it was some ghetto crap) but it ended up being that he just was just running to long of a stickout and an improper gun angle in certain areas and the cell exhaust system was blowing shield away.

No offense but your welders should know enough about the process to fix this problem themselves.

[Lewis]

No, we don't blindfold him we just make him sign a "mutual confidentiality" agreement. What can I say - I got a chuckle out if it also. Honestly, I do really appreciate all the help.

We use a mag particle inspection method to look for any bit of porosity and dig it out if anything at all is found, including any subsurface defects that could be as small as a pinhole.

[Hass]

Have them try welding with some different wire on random things?
Just to make sure they are even using proper gun angle and such?
Or maybe their stickout is too long? ventilation pulling away the shielding gas?
Could be just something like inexperienced operators -.-
Seems hasty to blame wire, as... well, if it's that secret of a project that you can't tell us what kind of wire it is, it has to be pretty expensive, which means a good quality control on the wire... which... means, good wire.

equipment could be worn... bad nozzle, clogged diffuser.. whatever.
all goes to the operator -.-

[jsfab]

Lewis, whatever happens, it would be appreciated, if you get back to us here, and explain it.

Not violating any classified information, of course.

Thanks.

[Lewis]

Some of the items you are talking about are definitely ones we are looking at - especially gas coverage being drafted, part cleanliness, torch angle, power, speed & feed & flow settings etc. We are going to run some tests on T-samples.

Just wanted to make one thing clear also - we are not blaming the wire at this point - just searching for facts. The supplier is working with us to resolve the issue and we may find the wire is just fine.

I'll try to report back when we learn something - without violating any classified information, of course.

[dougspair]

....well....I too have welded a lot of steel....and fair amount of stainless....and tons of aluminum also...with MIG....used several different brands of wire....and for steel porosity problems....the wire itself is likely the last place the problem will be....and most MIG wire does have a factory applied lube that would perhaps look like dirt....on a clean rag...
Couple shops I worked, the rolls of partially used wire were just tossed on the floor, kicked under the bench, thrown on a shelf....sat uncovered on the wire-feeder for months at a time........often covered with oily dirt.... and still welded pretty good....
I'd be looking at the gas flow rates, leaks in the gas lines and/or cuts in the outer rubber jacket of the MIG gun hose/cable assembly, then the metal surface...mill scale...oil....paint....water...anything even remotely called hydro-carbon will surely cause porosity....and how about any solvent/cutting oil solutions from previous operation....
Where I work now, California EPA mandates a water-based heated solvent type parts cleaner...the stuff will dry off after a few minutes on the 'cleaned' parts...but leaves a thin film on the stuff you just cleaned...I always rinse it off with clean water....otherwise any moisture will cause the dry film to once again turn to slippery soap....and can cause a problem with welding for sure...
Even a partially spatter-clogged MIG gun nozzle can upset the gas enough to be the culprit...

[transit]

How about investing in a two pound roll of wire from your local big box store, usually E71S-6, to see how it runs?