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Static-XJ

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Discussion starter · #1 ·
We just got a new wire at work. Lincoln Metalshield MC-706, AWS classification E70C-6MH8 .045", C25 gas.

Basically I'm looking for some tips from anyone that has run metal core wire before.

I've sort of settled into 29v, 360ipm, 220a. I have good weld appearance, and have not had any issues with undercut or cold lap. The major issue is spatter. I observed the least amount of spatter with 29v, 360ipm, but it's still far more than I would like, especially for a wire that is advertised as low spatter. I'm getting more spatter than with GMAW-short circuit or FCAW-gas shielded. I have been using sanding discs on an angle grinder to remove the spatter, as it adheres to the metal very well. I'm convinced that post-weld clean up time is greater with metal core wire due to the spatter. This is compared to gas shielded FCAW, easy to chip slag and spatter so fine that a quick pass with a wire cup on a grinder is all it takes.

Anyone have an advice for metal core wires?
 
#3 ·
Something is wrong. Perhaps if yo went to the lincoln website and got a Cheat sheet it would help.

I run metal core with no spatter unless I have no control of the gun with screwy gun angles or going around an outside corner.

David :)
 
#4 ·
The first problem is your gas. To use Spray you need less than 20 percent carbon dioxide. You can sorta spray at C20 but you really need something around 90 percent argon. I run around 28.5 volts and from 325 to 400 inches a minute. I have seen people run as high as 425 but the puddle is large on a horizontal and you can get undercut or roll over/cold lap on a horizontal fillet if you are not dialed in that day.
 
#5 ·
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#6 ·
go for a 90/10 mix and turn your wire down to no more than 300ipm and that spatter will go away real fast. you can leave the 29 volts right where it is. metalcore always runs better with an argon rich gas blend.
 
#7 ·
El_Lloydeo,
So are you recommending that he run outside of the manufactures recommendations?
 
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#8 ·
well im not too sure what the manufacturer recommends for this wire. im just telling him how to make a beautiful weld with beautiful machine settings. would you run an 1/8" 7018 vertical up at 145 amps just cuz the manufacturer says you can? the settings im telling this guy come straight a pre-qualified WPS . static xj, 90/10 27.5-28 volts 285-300 ipm and call me in the morning. you will love it there. and you will not have your spatter issue anymore.
 
#9 ·
El_Lloydeo,
Sorry to have to inform you of this but what you have listed is NOT prequalified. But I see that you are only concerned with a weld looking pretty. Who cares if the weld has any integrity. You seem proud of your position as a weld tester, but maybe you should review your code requirements. Let me help you. First we need to follow what the manufacture has recommended. From there we look at AWS D1.1 (08) 3.6, this is the section that deals with prequalified welding procedures. There are a few requirements to follow. We have (4) listed under this section 1) amperage, 2) voltage, 3) travel speed, and 4) shielding gas. What the code tells us is these variables must conform to the requirements of table 4.5. If we go to table 4.5 it lists amperage + or - 10%, voltage + or - 7%, travel + or - 25%, and shielding + 50% - 20%.
Now we have a reference of 27.5 to 28 (27.75 you have to start with a # not a range) volts for this range are = 25.8 to 29.6
For amperage we have 285-300imp (this equals 220amps & you need a # not a range) this range = 198 to 242 amps
BUT our manufacture references 23-28 volts and 280 amps
What this equates to is 25.5 volts at 280 amps(I set volts at mid way between recommendation) From that we can now set a range in accordance with AWS D1.1.
My range = 23.7 to 27.2 volts and 252 to 308 amps.
Your range = 27.5 to 28 volts and 198 to 242 amps
Your suggestions are out of the manufactures recommendations and out of AWS D1.1 prequalified ranges.
 
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#10 ·
i didnt mean to put prequalified, i was thinking about one of the joints we use for our metalcore certifications. what i meant was that we had a procedure qualified and the settings that i am suggesting seem to work the best. i know all about table 4.5 and all that crap. been a cwi/cwe for quite some time now and i use that table on a regular basis. we dont give a min. wfs but we do have a max of 400 ipm on our wps. 24-31 volts too. and i not only like my welds pretty i like them strong just like i like my coffee. the settings i listed may not work for him. depends on his skill. thats why i gave a range. but my students take this test in the 2G position. the higher your wfs goes the faster that weld is squirting out and the faster one has to move to keep it from falling all over the floor. so if you really think that my settings are bs, perhaps i could weld you up a test plate and ship it to you and tell me what you think then.
 
#11 ·
Based on my experiences with all manners of metal core and other cored wires, it is always best to follow the manufacturer's reccommendations.

If Lincoln says to use a certain mix of shielding gas with that wire, then that is what you should use.

In my experiences with the various metal cored wires made by Hobart, there is not one standard shielding gas mix. That means that one wire might run best with 98/2 Ar/O while another wire would run a very nice spray with 75/25 Ar/CO2. That is what the wires are designed to do.

Run with whatever the manufacturer suggests. Running a different shielding gas than what the wire is designed for will drastically change the weld metal chemistry and also the mechancial properties.
 
Discussion starter · #12 ·
qaqc said:
As others have mentioned, it appears that you are not running that wire as the manufacture recommends. We use a similar wire at my shop. When we run .045" it is at 32 volts and 300 amps. Here is a link to the manufactures recommended settings.

http://content.lincolnelectric.com/pdfs/products/literature/c311.pdf
Click to expand...
Thank you, I was poking around Lincoln's site yesterday trying to find a chart listing just that.

The product literature is listing 75-95% Ar balance CO2 for shielding gas.

It's even listing 75-80% Ar balance CO2 is required for AWS testing purposes, the M designator in the AWS classification for this wire (learn something new every day :) ). So the gas mix I'm using is OK per the manufacturer, the AWS, and my company's ASME Section XI qualified WPS. But that's not to say that the gas mix couldn't be the cause of the excessive spatter, it's definitely more globular like than spray like as I have been running it. I'm printing off the applicable page with Lincoln's typical operating procedures and going to try out several of the listed ranges. The setting I listed is very close to one of the listed ranges, accounting for the use of 75/25 vs the 90/10 gas mix the chart is evidently made from (+1 to 2 volts for higher CO2 gas mix).

I'll have to go check our bottle racks as I'm not sure what other Ar/CO2 mixes we keep on hand, we have a bulk mixer and C25 gas mix is available off a manifold at the wall about every 40'.

Thanks for the replies so far, if anyone has any more advice, keep it coming. :drinkup:
 
#14 ·
hey static ive never ran that stuff on 75/25 hows it run? with the 90/10 it has the most beautiful spray ive ever seen. i didnt know this wire would perform well with a gas like 75/25.
 
#15 ·
Static-XJ,
All we use for metal core is 75-25, it works great. You can set your parameters to what the manufacture recommends, and then fine tune to help with splatter. I'm not sure if it has been mentioned but if you have to ability to adjust your arc force, then it is helpful to turn it down for all GMAW and up for FCAW.

El_Lloydeo,
I had a feeling that you were not talking about a prequalified wps. Your max imp of 400 (=260 amps) would be running at roughly 25 volts. This has severely limited your use of the wire. You have cut off the upper end of the parameters. (260 to 360 amps) This takes away the main benefit of metal core wire. At those settings you are looking at a max of 9.4 lbs per hour. On the other hand if you use it to it's full potential you can run at 17.5 lbs per hour. This may be a bit much for most. I have my welders running at 13 lbs. This seems to be where there is the best combination of deposition and puddle control.
 
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#16 ·
since we use this as a test for 2G spray we also had to put these plates together and weld them in that position and yeah metalcore is a high dep. kinda wire but we usually administer this test with solid wire. we just use about the same parameters so that they can actually control their arc as its a pretty good size puddle for that position. they can run wherever they want from 24-31 volts and from 0-400 ipm according to the wps. we dont get many people requesting it though because if you certify with solid wire you are allowed to run the metalcore too. and vice versa. dont know why we even have the stuff to be honest.
 
#17 ·
ditto. What she said. :drinkup:

weldrwomn said:
Based on my experiences with all manners of metal core and other cored wires, it is always best to follow the manufacturer's reccommendations.

If Lincoln says to use a certain mix of shielding gas with that wire, then that is what you should use.

In my experiences with the various metal cored wires made by Hobart, there is not one standard shielding gas mix. That means that one wire might run best with 98/2 Ar/O while another wire would run a very nice spray with 75/25 Ar/CO2. That is what the wires are designed to do.

Run with whatever the manufacturer suggests. Running a different shielding gas than what the wire is designed for will drastically change the weld metal chemistry and also the mechancial properties.
Click to expand...
 
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#18 ·
A_DAB_will_do,
I'm sure if you are aware of this or not but look for metal core to be listed in the next AWS A5.20, or possibly the one after.
 
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#19 ·
It was not long ago.. maybe three years that any mention I made here about metal core was answered with a "huh? " In my area it has been in common use since the mid nineties. Good or bad it certainly has had code writers scrambling to define. Initially we could use it in a certified shop if we had flux cored certifications. It was simply treated as a type of flux core. Now qualifications are completely separate.
You can love it or hate it but it is certainly here to stay.
 
#20 ·
Yes, I agree that metal core tubular wires are here to stay. The use of a C-25 shielding gas with metal cored wire for commercial or code quality welding is rare. A C-10 is typical. Higher argon results in increased tensile and yield strength. Some E70C-6M products approach 100 ksi tensile, so it is a good idea to share that data with engineering.

Higher argon does increase the droplet rate in axial spray metal transfer, finer droplets, and argon does help to retain alloy (silica and manganese). This is primary to higher tensile and yield strengths. As tensile properties increase, then ductility tends to decrease.

Higher spatter levels indicate that either the mode of metal transfer is below the axial spray transfer threshold, transition current. The other more potent reason is arc voltage - adjustments upwards for a given wire feed speed ought to get you away from globular transfer and short-circuit events.

Best regards,

J Nadzam
Lincoln Electric
 
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