Short Circuit Transfer Mode

Date 12-02-2008 04:49

dbigkahunna,
Check out this posting.

http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=57924;hl=Modes%20of%20transfer%20FCAW

Most of the top brains on the forum have contributed to it and there is even a response from Lincoln to a question by eekpod so hopefully that will clear it up for you,
Cheers,
Shane

By js55

Date 12-02-2008 13:48

I've had flux core down so low it barely stayed lit (welding 1/16" on 2" pipe in position) and it still was not in short circuit. I don't think you can get it in short circuit though I've never really tried. That low, its globular. I would think that in order to get the current density and voltage low enough to make electrical contact (remember the wire sheath will have a smaller cross sectional area than even .035" solid wire)in a manner to initiate a consistent short circuit transfer that the flux would interfere with the process. The basic answer to the question would be no.

By motgar

Date 12-02-2008 15:20

dbigkahunna,

So the question is: Is fluxcore w/o gas welding considered to have the short circuit transfer mode?

Do you have access to Section II, Part C of ASME? If so turn to page 455. There is a heading: A7. Description and intended use of Flux Cored Electrodes.

If you are looking for self-shielded electrodes, then look up EXXT-3, T-4, T-6, T-7, T-8, T-10, T-11, T-13, and T-14 classifications.

From what I can see, a T-13 classification might fit your question. Self-shielded, operate on DCEN, not DCEP as most common. Usually welded with short-arc transfer. The slag system is designed for all position root passes, on circumferential pipe welds. Can be used on all pipe wall thicknesses but, only recommended for the first pass.

Since you reference B31.3, I figure you will be doing some pipe welding.

Hope that helps.

By hogan

Date 12-02-2008 16:49

dbigkahunna,
It sounds to me like you might be confusing GMAW and FCAW. FCAW runs with gas (FCAW-G) or without (FCAW-S). Transfer is not a variable. GMAW can change transfer mode based on shielding and voltage. low volts = short circuit, mid volts = globular, and higher volts = spray transfer. This is a very basic description. "GMAW fluxcore" is describing two different welding processes. GMAW is further broken down into solid wire and metal cored wire. We have changed to mainly utilizing metal core and are very happy with it. It runs a little hot but fusion and deposition are great.

By swnorris (****)

Date 12-02-2008 18:08

dbigkahunna,

Short circuiting transfer is typically associated with the GMAW process. Assuming you're welding mild carbon steel, short circuiting transfer is typically done with low currents (around 19 volts +/-) and small (.030 to .045) diameter wires. With the shielding gas, argon is the dominant gas in the mixture, with the carbon dioxide content reduced to 20 to 30%. Other mixtures with higher percentages of carbon dioxide also render short circuiting transfer, with 100% CO2 providing the greater penetration. The technique results in low heat input, which minimizes distortion.

By 803056

Date 12-02-2008 21:31

Hello Scott;

Did you intend to say low voltage and low current?

Best regards - Al

By swnorris (****)

Date 12-03-2008 11:18

Oops.

By ssbn727 (*****)

Date 12-07-2008 05:03

Must be all of those "Alien Tanks" he's having "Mental Battles" with... Isn't that right Scott? :) :) ;) ;) :)

Merry X-mas My dear friends, and colleagues!!!

Respectfully,
Henry