Dirty? Wire

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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?
Reply: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.Have we all gone mad?
Reply:Who is manufacturing the wire?  Have you checked the spools for residual magnetism?  Where/how is the wired stored and packaged?
Reply: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?
Reply:Copper, black. I’m thinking copper -sulfur or iron sulfer contamination. Any sulfur compounds being used, airborne hydrogen sulfate gas? Rotten egg smell?
Reply: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.
Reply:what are they saying the dirty mig wire is doing?porosity? not feeding properly?
Reply: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.
Reply:Originally Posted by LewisPorosity 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.
Reply:Just throwing this out from the Lincoln Electric site on common causes of porosity:http://www.lincolnelectric.com/knowl...ntent/gmaw.aspCommon Problems and Remedies for GMAWReprinted with permission from the September/October, 1997 issue of Practical Welding Today magazine, copyright 1997 by The Croydon Group, Ltd., Rockford, ILIn 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 PorosityPorosity Problem #1: Improper Surface ConditionsThe 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. RemediesTo 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 PropertiesAnother 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.
Reply:120 s-what.  How about trying another brand?
Reply: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
Reply: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.
Reply: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.
Reply:Good one man. Got a chuckle out of me.
Reply: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
Reply: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.
Reply:Originally Posted by jsfab The reason being they have already included the correct lubes neccessary for the wire to run thru the liner.
Reply: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.
Reply: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.
Reply: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 -.-
Reply: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.
Reply: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.
Reply:....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...Dougspair
Reply:How about investing in a two pound roll of wire from your local big box store, usually E71S-6, to see how it runs?Originally Posted by dougspair  Even a partially spatter-clogged MIG gun nozzle can upset the gas enough to be the culprit...
Reply:You may want to change gas, just to hit all the bases. I used to work with guys that were doing basic research on weld metals, the real deep metalurgical stuff. We would try about a dozen different mixes, and delivery methods, Argon, co2, helium, oxygen, hydrogen, sometimes nitrogen, all in 5% steps. section and etch the welds to determine the best for a given base metal and wire. analyzing penetration, grain growth, transmetalic compounds,  wetting, porosity, alloy effect, (nitrogen will combine with  ti, co2 with iron in others, oxygen with silicon) etc. AWS journal articles etc. Nickel superalloys, titanium, stainless, carbon steel, lithium -aluminum etc the whole bunch.  We had some lots of gas that were bad. inadequate purging, and stratification,  last year I had a bad mix, too much oxygen, with marginal steel and personel it just made a foam of the weld metal. With perfect technique it was ok, with anything off, in this case the steel alloy, it was impossible. A few years ago we used to use a gas manifold that ran around the shop, a couple hundred feet of pipe. At restart after a shutdown it gave us bad gas until it got purged out completely. and each regulator had to be purged as well. .      I'm with  Transit, get a roll of generic wire, and a couple of bottles of pure gas, argon and co2, see if you can get a good weld on 1010 steel, so as to rule out the air currents, stickout etc, then change one thing at a time until you get good results.           Don't rule out bad steel, we had some lots from some US minimills, that were as stringy as  wrought iron, think of string cheese.  and brittle as glass. It would snap or tear out like a glued wood "t" joint. A lot of the chinese steel is like that as well. We had one air tank that we modified to a vacuum ballast tank, that had so much silicon it was nearly unweldable.   Alloy control is pretty difficult when they use a single melt from scrap to rolling mill.      As for the lube, or black stuff, the mill may have changed something since the material was qualified, or it may have been qualified clean. You may also be seeing a reaction with the acetone. Acetone is a reactive chemical with some metals.      IF you are using the new "one pulse, one droplet" transfer procedures, we did some work on them over the years. Mig, wire fed tig, and laser. Bleeding edge stuff. The idea was to limit energy transfer into the base metal.  What I noticed was that they are super picky about contamination. There is not the heat there to fully vaporize and blow out the contaminants. It provides only enough energy to melt the end of the wire, melt a micro puddle to receive and bond the droplet, plus ever so little to allow wetting,and then it goes to the next drop. . it makes steel  as picky as aluminum about contamination. a little more background amperage may help, but if you are working with a defined process, you may be stuck cleaning.    If the wire is the rolled tubular stuff with a seam down the side, it may also have absorbed some lube into the flux, we had that problem as well. Moisture will leave when you heat the wire and store it hot, it just increases the transfer of the lube into the flux however. With more heat, contamination burns away, with tight amp limits it can drive you nuts.    Dirt or lube pickup from the liners, binder resin from abrasive wheels or belts, rust preventative migration on the base metal, excess fume removal velocity, volatiles pulled into the weld zone with air from hot surrounding metal, dirty gloves, (or new gloves with oils in the leather), synthetic gloves with plasticizer, dirty gas, bad mix, contaminated shot blast media. Spatter sprays and tip gels that have little effect on most shop welds can also play hob with some processes. Some guys use more when under stress.    Look at the whole process, good quality control procedures include all the personnel, most important, don't threaten any jobs, you need all the brains to find and fix problems. Stress kills quality. Pride in a good job is essential, but fear will kill it.Last edited by wesdavidson; 11-07-2009 at 03:46 PM.past work toys; lathes,mills, drills, saws,  robots, lasers ironworker, shears, brake, press, grinders, tensile tester,  torches, tigs, migs, sticks, platten table, positioner,  plasmas , gleeble and spot. Retired June 30, 2009.
Reply:I have a little bit of info here on mig welding wire.It covers some basic stuff that most people are not aware of in mig wire.  Although it may not help you out with you problem specifically it could offer some ideas.
Reply:The other day, I started getting a little porosity and after I checked everything obvious (nozzle, gas level in the bottle, etc), I ended up pulling the gun out of the wire feeder and sure enough, one of the o-rings was worn out and allowing air to be introduced into the system.You might check the o-rings on the end of the gun that is towards the wire feeder.