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10th Apr 2009, 07:53 PM #1Pink 10EE owner
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Electrode positive or Electrode negative
I have a Miller BlueStar 185DX welder..It is a 180amp DC engine driven welder/generator..(really nice machine)
As such you can run your electrodes either positive or negative.. What are the advantages of each style of connection??
I always run everything electrode positive..Is that the right way to go??
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11th Apr 2009, 01:42 AM #2
G,day RC,
In a nut shell it is all about heat balance,as required by the type of electrode to suit the material your are welding.
Roughly speaking 1/3 & 2/3rds heat distribution.
Electrode negative 2/3 rds in the work and 1/3 electrode.
On alloy steels and s/steel where heat could change heat treatment and temper values(or cause distortion in SS) you use electrode positive and get 1/3 rd in the work and 2/3 rds in the ro.
You will notice that as you get down towards the butt end of the rod it tends to glow red hot if the amps happen to be even a smidgin too high..
I like the arc electrode positive provides it very controllable for positional work with LH rods, Though use it it on GP rods and you overheat the fluxes.The general purpose rods do not tolerate the heat too well.
Plus, the rod designation number gives the the clue what to run them on. Low Hydrogen and similar electrode + E7016 its 1 in the 3rd number.In Gp rods it is 2 as the third number as in E6012
Of course the directions on the package will have that info ,but if you are like me you are not in the habit of reading them until there is a problem.
cheers
Grahame
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11th Apr 2009, 12:19 PM #3Pink 10EE owner
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Thanks for that explanation Graham, but another question which is a bit off topic...
I read a lot of US forums and they seem to wholly use E7018 rods over there for their plain jane low hydrogen....We here seem to use E7016... In fact I went into my welding supplier and asked for a packet of 3.2mm E7018 rods and the salesman went "huh???".. But they all know what E7016's are...So what is the difference??? Is it just the E7018's are iron powder???
I knew that Ferrocraft 61's are E7018 and I find them a much nicer rod to use then E7016's
I have the "Lincoln Procedure Handbook of arc welding and it says here in a table of Characteristics of Mild Steel covered electrodes that E7016 is not mentioned because of it's limited usage..
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11th Apr 2009, 03:15 PM #4
Hi RC
I am reasonably sure <within the confines of an oft failing memory> that 7018 fall under a semi or maybe a low iron powder designation.
This will be the very reason why you find them easier to use and also that they give you a better appearance and can be "walked " along the bead, meaning that they burn well at short arc, actually supported on the outer shell of the flux covering.
"Gunbarrel" I think this was the term used - really a bit counter sinked with the filler wire arcing off inside the depth of the counter sink.
If they are like the "old" 61Lt's electrodes used to be in the good old days -yada yada - the deposited slag cover will scorpion tail as the weld bead cools
They will also run fairly good on AC as well.
Well I have read a bit on a certain welding forum ( Zap ! if ya can't tig its not worth talking about!-know the one?) and reckon they don;t know much more than 6011 and 7016;s Ferrocraft 61's.Maybe its just be,Possibly I am just an old grumpy curmudgeon.??? LOL!
The electrode came into favour bigtime as the mining industry kicked off as it was capable of multi positional work with a good yield strength resistant to cracking issues on earthmoving equipment.
It also worked well for me at places like QAL where for a job of welding in instrument probe sockets, it was ideal was to provide Xray quality deposits on H.Pressure heater shells and give a superb appearance as well..
Grahame
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25th Apr 2009, 12:56 PM #5Intermediate Member
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Graham are you sure you have your negatives and positives around the right way? I thought it was opposite.
RC the 18's as Graham said have a little iron powder and have fast freezing weld pool characteristics. They are exceptional for positional (vertical/overhead) welding of fillet welds on many different materials and thicknesses. 16's are more fluid and are generally a better choice for butt welds, especially root runs. Kobe LB52-18 and Ferro 61 are the most readily available 18's that I know of.
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25th Apr 2009, 06:24 PM #6
Hi
Unless my Australian Standards Electrode Classification code books are wrong
Exx1x - All positions.
Exx2x - Flat and Horizontal Positions.
Exx4x - Vertical down position.
Exx10 - DC, reverse polarity.
Exx11 - AC or DC, reverse polarity.
Exx12 - DC, strait polarity, or AC.
Exx13 - AC or DC, strait polarity.
Exx14 - DC, either polarity or AC (iron powder).
Exx15 - DC, reverse polarity only (low hydrogen).
Exx16 - AC or DC, reverse polarity (low hydrogen).
Exx18 - AC or DC, reverse polarity (iron powder, low hydrogen)
Exx20 - DC, strait polarity, or AC for horizontal fillet welds; and DC, either polarity or AC for flat position welding.
Exx22 - AC or DC, either polarity (high iron oxide).
Exx24 DC, either polarity or AC (iron powder).
Exx27 DC, strait polarity. Or AC for horizontal fillet welds; and DC, either polarity, Or AC, for flat position welding (iron powder)
Exx28 - AC or DC, reverse polarity (iron powder, low hydrogen).
Exx48 - AC or DC, either polarity (low hydrogen, iron powder).
Heres a bit of stuff that I cut and pasted from the Miller & Lincoln sites .
The terms "straight" and "reverse" polarity are used around the shop. They may also be expressed as "electrode-negative" and "electrode-positive" polarity.
Polarity results from the fact that an electrical circuit has a negative and a positive pole. Direct current (DC) flows in one direction, resulting in a constant polarity. Alternating current (AC) flows half the time in one direction and half the time in the other, changing its polarity 100 times per second with 50-hertz current.
A welder should know the meaning of polarity, and recognise what effect it has on the welding process. It is the ability to adjust polarity that lends DC welding kits versatility. With few exceptions, electrode-positive (reversed polarity) results in deeper penetration. Electrode-negative (straight polarity) results in faster melt-off of the electrode and, therefore, faster deposition rate. The effect of different chemicals in the covering may change this condition. The high cellulose covered mild-steel rod, is recommended for use on positive polarity for general welding. They are Id by a 6010 number
What are the differences between 7014, 7018 and 7024 electrodes? When should they be used?
7014 electrodes produce about the same joint penetration as 6012 electrodes and are designed for use on carbon and low alloy steels. 7014 electrodes contain a higher amount of iron powder, which increases deposition rate. They can also be used at higher amperages than 6012 electrodes.
7018 electrodes contain a thick flux with high powder content and are one of the easiest electrodes to use. These electrodes produce a smooth, quiet arc with minimal spatter and medium arc penetration. Many welders use 7018 electrodes to weld thick metals such as structural steel. 7018 electrodes also produce strong welds with high impact properties (even in cold weather) and can be used on carbon steel, high-carbon, low-alloy or high strength steel base metals.
7024 electrodes contain a high amount of iron powder content that helps increase deposition rates. Many welders use 7024 electrodes for high-speed horizontal or flat fillet welds. These electrodes perform well on steel plate that is at least 1/4 inch thick. They can also be used on metals that measure over 1/2 inch thick.
When you are welding polarity =electrode+ (dc reversed) you get more penetration.
If you go e- (dc straight), the penetration will be less, but you will lay more weld.
Hope this helps to promote a better understanding.
Grahame
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25th Apr 2009, 07:44 PM #7
Apologies to Spooled
and Thanks to Stringy
Yep I got RRs about on negative electrode 2/3rds heat in rod and I/3 in work and Viccy versa for the E +.
I double checked it on the TWI site ,
Grahame (foot in mouth) Collins
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25th Apr 2009, 07:50 PM #8New Member
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Electrode +ve or -ve
Grahame,
I am very new to this game, and thankyou for all the good info so far. During this last week I bought a BOC Smootharc 130.
I anticipate only welding RHS, angles and flat steel to 3mm thickness around the home. I have 2.5mm Metalcorp 6013 rods and Gemini 2mm 6012 rods. I have two questions -
Are these rods suitable for my welding requirements?
Do I connect the electrode holder to the +ve or -ve terminal? (The manual only shows a sketch set up for DC operation - holder to -ve).
Thanks, Alf.
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26th Apr 2009, 12:39 AM #9
Those electrodes will work fine on electrode negative.
Keep your arc shortened with the 6013- as they can be subject to flux inclusion (slag holes) if the arc is bit too long and amps a down a few points.
The inverter will hold the arc even if you are touching.
With those rods you should be able to see the flux curl up behind as it cools.
Grahame
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