fluxcore vs solid wire

Why is it you can weld thicker metal with flux core than with solid mig wire? I have one of the portable Lincoln 170 amp mig welders & have to change from solid to fluxcore when I need to weld thick steel plate.

[cutter]

Originally Posted by metalneck78

Why is it you can weld thicker metal with flux core than with solid mig wire? I have one of the portable Lincoln 170 amp mig welders & have to change from solid to fluxcore when I need to weld thick steel plate.

Mostly because the shielding gas cools the metal at the same time the arc is trying to melt it.

[X-ray]

Dont know if this will help or confuse, but it will give you something to read: http://www.weldreality.com/discussio...asp?PostID=241

Looking foward to what the welding hoodlums have to say about this solid vs. flux core topic

Oops, danga your fast Cutter

[Franz]

Fluxcore and MIG are actually different processes done by the same machine.
Fluxcore is very similar to stick, with the difference being the flux is inside the electrode rather than on the outside of the electrode as it is in stick. The flux allows the wire to act differently than wire within a gas shield.
Also, there is definitely a lot less depositable metal in a foot of .035 fluxcore than there is in a foot of .035 solid wire. Less metal means the same amount of electrical power in the arc gives you more heat. More heat means you can deposit more metal, and dig deeper, even if it takes more feet of wire to do it.

[DDA52]

Didn't I read somewhere, not sure where, that flux core was closer to spray transfer with solid wire than short circuit?? Or did I make the coffee too strong this morning?

Thanks for the help, think I sorta understand how it works now. Looks like I need a bigger machine, or keep switching out my wire. Makes sence to me now why I have to weld much slower when using fluxcore.

[JTMcC.]

Current density (the ratio of current to the cross sectional area of the wire), the resistance heating of the relative (compared to solid wire) small/thin wire results in higher deposition rate. And the small cross section current path makes the arc stream assume a narrower shape, that results in more penetration.

JTMcC.

[cutter]

Originally Posted by Franz

Also, there is definitely a lot less depositable metal in a foot of .035 fluxcore than there is in a foot of .035 solid wire. Less metal means the same amount of electrical power in the arc gives you more heat. More heat means you can deposit more metal, and dig deeper, even if it takes more feet of wire to do it.

Now, this is where the logic begins to break down for me: if amperage increases with the amount of metal being fed into the weld (via increased wire speed), and if there is less metal in flux core (being a hollow tube) than in solid wire, then how does the resulting lesser amount of metal being deposited add up to greater heat?
Moreover, consulting the omnipresent door chart settings for 1/8th in. metal & using .035 wire for instance, with fluxcore the numbers are 14.5 volts at 180wfs while for ER70S-6 solid wire with C-25, it recommends 17.0 volts at 245 wfs. So again, I ask how does that result in more heat with fluxcore wire?

[Markopolo]

Originally Posted by cutter

Now, this is where the logic begins to break down for me

...............

I hate to say this, (and I agree with you about the logic part).....but sometimes "logic" needs to be thrown out the window !

Case-in-point: When I was in embalming school, there was a fluid company that marketed an oil-based embalming fluid. (solouble oil, evidentally).......I asked the rep. "How can an oil-based fluid do it's job (embalming fluid, by it's very nature, has to easily penetrate tissue) when bodies are primarily water ?

He just smiled at me and asked: "Have you ever used this fluid" ? I said "Yes".....He said: "Did it do the job" ?....I said: "Yes".......He then said: "Then what are you complaining about" ?

MORAL OF THE STORY: "If it works, don't try to find a problem with it" !

[JTMcC.]

Originally Posted by cutter

Now, this is where the logic begins to break down for me: if amperage increases with the amount of metal being fed into the weld (via increased wire speed), and if there is less metal in flux core (being a hollow tube) than in solid wire, then how does the resulting lesser amount of metal being deposited add up to greater heat?
Moreover, consulting the omnipresent door chart settings for 1/8th in. metal & using .035 wire for instance, with fluxcore the numbers are 14.5 volts at 180wfs while for ER70S-6 solid wire with C-25, it recommends 17.0 volts at 245 wfs. So again, I ask how does that result in more heat with fluxcore wire?

200 amps is 200 amps, wether your using it to melt a stick electrode, a solid wire or a flux core wire.
But when you are melting a flux core wire you really get maximum bang for your 200 amp buck. Like I said, the 200 amps are focused into a narrower arc stream with flux core, giving you quite a bit more penetration. And, the flux core wire is resistance heated much more than the solid wire (because of it's smaller cross section area) and is almost at it's melting point when it reaches the arc, this gives you big time deposition. Those two things let you wring the most work out of whatever amount of amperage you have to work with.
Current density, it's where it's at with cored wires.


JTMcC.