Stainless Fluxcore

By Lawrence (*****)

Date 04-10-2009 04:33

I just demo ran some new Lincoln gas shielded stainless FCAW and it ran vert pretty much like E70T-1. Really nice... and we were running on 1/4 inch so I didn't really think we would be able to carry the puddle... We ran weaves... Very nice.

Are you weaving or running stringers?

What brand wire?

What diameter wire?

What wire feed speed are you trying to use?

By steelman7018 (*)

Date 04-10-2009 13:02

Washington Alloys, 035, vee groove, stringer or weave

By TimGary (****)

Date 04-10-2009 12:06

Flux core SS burns best with 98% Argon and 2% oxy. This gas helps it wet in on the edges very well. Doing a nice vertical bead is all about getting your heat and travel speed tuned in to what works best for you . Then you can just run straight up with no weave at all. It helps to keep your clean nozzle at 90 degrees from the surface and a short contact tube to work distance.

IMHO
Tim

By darren

Date 04-10-2009 19:56

27 sounds awfully high volts try around 24.5 to 25 put in enough wire to cool puddle, don't know what the "/min would be.
just my 2 cents

By PhilThomas (**)

Date 04-11-2009 11:40

Try 300 ipm wire and about 26 volts. You have to keep the stickout short (1/2" max) and no angle to the torch. You have the right gas with 75/25 Ar/CO2 - don't change that. If the bead is high in the center, you may be weaving too slowly across the middle....get across the center more quickly and hold a bit more at the toes.

By TimGary (****)

Date 04-13-2009 11:55

PhilThomas,

Have you ever run SS FCAW with 98/2 gas?

Tim

By Lawrence (*****)

Date 04-13-2009 15:03

Tim,

Is there an actual Stainless FCAW manufacturer out there who recommends gas mixtures 98% argon rich?

Just don't see it as a good idea for the forum to suggest something that the manufacturer is unwilling to do.

"∗Gas mixtures of more than 75-80% Argon is not recommended."

http://www.hobartbrothers.com/pdf/datasheets/ChromaWeld308LT1.pdf

http://www.hobartbrothers.com/products/McKay/ChromaWeld_309LT1/

http://www.hobartbrothers.com/pdf/datasheets/ChromaWeld316LTO.pdf

Ar + 15 - 25% CO2 offers the best weldability,
but 100% CO2 can also be used (voltage
should be increased by 2V).
Gas flow rate 20 - 25 l/min.
http://www.avestawelding.com/4008.epibrw

By TimGary (****)

Date 04-13-2009 17:06

Lawrence,

Very interesting...
I see I'm going to have to do some research.
I'm having trouble figuring why the high argon content would be problematic, especially since 100% Ar is used in GTAW.
Maybe it has something to do with the flux?
I'm going to have to look into it.
All I know at this point is that the difference when actually using 98/2, as far as bead profile and wet toes is concerned, versus 75/25, is like night and day.
Thanks for the heads up.

I miss Chuck Meadows, may his generous soul RIP.

Tim

By defaced (**)

Date 04-13-2009 20:13 Edited 04-13-2009 20:16

"I'm having trouble figuring why the high argon content would be problematic, especially since 100% Ar is used in GTAW."
FCAW and GTAW are two different worlds because in FCAW metal is being pushed across the arc, in GTAW you're just using the arc as a heat source - at least you hope. FCAW likes an active gas (O2 or CO2) to help the arc stabilize. What works for one does not always work for the other.

I've always heard of 98-2 as being predominately used for SS solid wire in spray mode.

By PhilThomas (**)

Date 04-13-2009 17:41

Tim - as mentioned below, that gas is not recommended for SS FCAW. Our wire is also designed for 75/25 or 100% CO2.

Have you ever welded a tensile with the 98/2 gas and checked the properties? I suspect that the addition of oxygen would cause some problems.

By js55

Date 04-13-2009 20:38

Theoretically I suppose as the argon content in the gas goes up, the recovery of elements across the arc increases, predominantly Cr and Mo which would be those alloying elements most likely to be oxidized I think. This, it seems to me would increase the corrosion resistance, the tensile strength, and the ferrite, since Mo and Cr are ferrite stabilizers. But in all, I think the difference would be negligable. IMO, if the stuff welds well I'm not sure what the problem would actually be.
The biggest issue would be, as Tim mentioned, puddle edge wetting and edge penetration, since the mass of argon tends toward a more fingered narrow arc profile. CO2 broadens the penetration pattern. Or perhaps that those compounds in the flux intended for deoxidation would end up either in the slag or the weld metal.
Is this critical?
I would have to say that IMO the advantage of the heavy CO2 mixes for SS is economics more the metallurgy or mechanicals. The disadvantage of a higher argon mix would be the greater skill required to ensure good fusion under the entire bead from toe to toe.

By Zeke

Date 05-22-2009 15:50

Although welds can look acceptible with the higher Argon mixes, CO2 is needed for penetration. I have tested these wires with all sorts of gas mixtures. The mechanicals and corrosion properties were fairly close, but the noticible difference is the lack of penetration with anything that contains less than about 20% CO2.