I have a question about 'POLARITY'.
Most common carbon steel must be welded with DCEP in SMAW and MIG.
What happen with DCEN ?
On the contrary in TIG welding DCEN is used..
I heard that the electron makes it high temperature by hitting the material connected with positive pole.
But I don't know why opposite polarity is used in SMAW and TIG.
As the aluminum is welded with DCEP in MIG, is it available to weld aluminum with DCEP in TIG ?
How about including this into 'TIG welding basics overview' in YouTube ?
Artie F. Emm
- Artie F. Emm
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Generally speaking, in an electric circuit power flows from negative to positive. In an EN scenario electricity flows from the torch to the weld metal, and opposite for EP.
Heat concentrates on the positive end of that exchange, which is why TIG DCEN on steel gives good penetration. TIG DCEP is do-able but requires a large tungsten electrode because in that context heat concentrates in the electrode (the "positive" side of the arc). On my very first ever TIG outing I reversed the leads and tried DCEP on steel: smoked the tungsten, not a good start.
You can think of AC TIG welding on aluminum, for instance, as an alternating mix of DCEN and DCEP: the A/C sine wave moves through a "hill" above the line and a "valley" below the line.
DCEN on aluminum is possible, and I for one will be interested to see the video mentioned here:
http://forum.weldingtipsandtricks.com/v ... 521#p38521
Gas shielded GMAW is DCEP while FCAW is typically DCEN. I *believe* that polarities vary in SMAW, to some extent at least, to exploit differences in the way flux coatings react during the weld process, but I'm sure I'll get corrected on that one.
Welcome to the forum!
Heat concentrates on the positive end of that exchange, which is why TIG DCEN on steel gives good penetration. TIG DCEP is do-able but requires a large tungsten electrode because in that context heat concentrates in the electrode (the "positive" side of the arc). On my very first ever TIG outing I reversed the leads and tried DCEP on steel: smoked the tungsten, not a good start.
You can think of AC TIG welding on aluminum, for instance, as an alternating mix of DCEN and DCEP: the A/C sine wave moves through a "hill" above the line and a "valley" below the line.
DCEN on aluminum is possible, and I for one will be interested to see the video mentioned here:
http://forum.weldingtipsandtricks.com/v ... 521#p38521
Gas shielded GMAW is DCEP while FCAW is typically DCEN. I *believe* that polarities vary in SMAW, to some extent at least, to exploit differences in the way flux coatings react during the weld process, but I'm sure I'll get corrected on that one.
Welcome to the forum!
Dave
aka "RTFM"
aka "RTFM"
- MinnesotaDave
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Stick can be run AC, DC+, or DC- depending on the situation.
Here is a chart for the result: (stick welding)
Here is a chart for the result: (stick welding)
- image.jpg (39.23 KiB) Viewed 2679 times
Last edited by MinnesotaDave on Sun Aug 24, 2014 8:57 am, edited 1 time in total.
Dave J.
Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~
Syncro 350
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Tried being normal once, didn't take....I think it was a Tuesday.
Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~
Syncro 350
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MM210
Dialarc
Tried being normal once, didn't take....I think it was a Tuesday.
Artie F. Emm
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MNDave, the chart you posted is specific to stick electrodes, correct? It is opposite the polarity characteristics of TIG.
Dave
aka "RTFM"
aka "RTFM"
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syncrowave 250
miller 140 mig
hypertherm plasma
morse 14 metal devil
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Yes, the chart is for stick welding.Artie F. Emm wrote:MNDave, the chart you posted is specific to stick electrodes, correct? It is opposite the polarity characteristics of TIG.
Dave J.
Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~
Syncro 350
Invertec v250-s
Thermal Arc 161 and 300
MM210
Dialarc
Tried being normal once, didn't take....I think it was a Tuesday.
Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~
Syncro 350
Invertec v250-s
Thermal Arc 161 and 300
MM210
Dialarc
Tried being normal once, didn't take....I think it was a Tuesday.