flux core help

Date 03-08-2007 16:48

I'm looking into getting a wire feed welder. I've used MIG in the past, but a flux core setup would be a little cheaper for me to get into, and also work a little better for welding outside (Argon would blow away).

While looking into the prices of flux core wire, I'm running into wires (i.e. 71T-1) that say they produce X-ray quality weld deposits using either 100% CO2 or a 75% Ar/25% CO2 mixture shielding gas.

But, if this is flux core, shouldn't the shielding be in the flux? What is the purpose of using flux core if I have to turn around and hook up a CO2 bottle?

Is this just something particular of the 71T-1 wire, or are most flux core wires this way?

By aevald

Date 03-08-2007 17:04

Hello jp2welder, simply put, flux-cored gas shielded wires are sometimes referred to as dual-shield wires. As you asked in a sense, they use a gas shield in combination with a flux core to provide shielding and additional alloying elements for the weld metal, in this case the flux doesn't provide complete protection for the welding arc. Gasless flux-cored wires incorporate both the shielding provisions and alloying elements in the flux core. The Lincoln trade name is often referred to to describe this process as "innershield", but it is actually gasless flux-cored welding. Hope this has helped in the explanation, you are also right when you said that the gasless flux-cored process is applicable for outdoor use and the dual-shield flux-cored process is better suited for indoor use. One other major difference between the two has to do with metal deposition rate, the dual-shield process is generally much faster and the gasless flux-cored method is much slower, more in line with stick welding minus the rod-change down time. Regards, aevald

By jp2welder (**)

Date 03-08-2007 17:20

Fantastic! I love this board. Thanks!

That goes for you too, down there, Hogan.

I hate looking/feeling like an idiot in the welding supply store, but I don't mind asking my "I'm an idiot on this subject" questions here.

By darren

Date 03-08-2007 23:03

the only "idiot" is the one who is afraid to ask questions. one of the most dangerous personality types in any industry. you have proven you are not an idiot by asking a question. any question is not only ok but welcome.
darren

By hogan

Date 03-08-2007 17:05

fcaw can be put into two catagories. first is self shielded (FCAW-SS) where the flux in the core of the wire provides shielding, and second is dual shield (FCAW-G) where a combination of gas and flux in the core provide shielding. typicaly fcaw-ss is used in the field and fcaw-g is used in fab shops.

By hogan

Date 03-08-2007 17:06

beat me to it

By 357max

Date 03-09-2007 15:57

Read the flux core wire manufacturer's data sheets.
AWS E71T-GS is a gas less flux cored and it is a SINGLE PASS ONLY weld deposit by most manufacturers. Some manufacturers limit the depth of deposit to 3/8 inch or 3/4" or 1".
The E71T-G is usually a gas less multiple pass weld deposit wire.
The AWS E71T-11 is gas less and it a is multipass usually up to 3/4 or 1" deposit depth. Some of the self shielded flux cored wires like E71T-8J may be low hydrogen weld deposits others may not.
Some of the external gas shielded flux cored wires may be low hydrogen or they may not. The shielding gas may be carbon dioxide or an argon carbon dioxide mixture or both. It may be carbon dioxide only or argon carbon dioxide mixture only and the mixture may be a limited range of 75-80% argon with the balance carbon dioxide.
The E70T-4 classification has the "0" as a designator for flat and horizontal weld position.
The E71T-4 classification has the "1" as a designator for all weld positions. Manufacturer may limit wire diameter that may be welded out-of-position.
Some self shielded flux cored wires are DC Electrode Negative some DC Electrode Positive. The same for the gas shielded flux cored wires.
And wire manufacturers may designate a particular wire be used only with a constant voltage power source. Others may use a constant voltage or constant current power source with a voltage sensing/following wire feeder.
Again read the wire manufacturers data sheets.