Welding wire speed

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Hi everyone. Just 2 quick questions. Firstly is there a difference between a mag wire feed unit and a mig wire feed unit. I have a mag wire feed connected to my 3 phase mig plant. I noticed that when a pull the trigger on my torch  i get the desired wire feed rate. then when i arc the torch for welding the speed is much quicker? is there 2 speeds? one when not welding and one when you are welding. Also i knoticed that when i change the wire speed not the voltage the current increase and decreases? i thought the current does not change until you change the voltage. Can anyone help me with this? Thanks.
Reply:Hello ericwoods, I believe you are using terms that are european (mag) and american (mig) for discribing the same process. As to your other question, some power sources have lead-in speeds on their feeders that are possibly a percentage of the selected speed and once the arc has been initiated they ramp-up to the speed selected by your speed setting on the feeder. As to your other concern, CV output which is common for most wirefeed processes, is also sometimes called CV/VA, meaning: constant voltage, variable amperage/current, you select the voltage and the power source tries to maintain a particular voltage, as you increase or decrease the wire speed the amperage is increased or decreased as well and in turn. So you aren't seeing things and it's supposed to work that way. That's the quick rundown. There are certainly more details that could be added to this response, however this is the basic description for what is happening. Best regards, Allanaevald
Reply:Hi Allan, thanks very much for your reply. Im trying to get the best welds possible from my machine. The Mag and mig terms are used to describe Metal Inert Gas welding and Metal Active gas welding. From what i understand in mig welding the gas is really only to shield the weld pool from impurities but in mag welding the gas plays a more active role in the weld pole. I think pure argon is formig and co2 is for mag. Im open to correction. Im here in Dublin, Ireland. Thanks again for your reply.
Reply:When welding with steel, a small amount of oxidizing gas (either a few % of O2 or greater amount of CO2) will increase the "wetting" ability of the filler; a trace of oxides decrease the surface tension of the molten metal. To make sure that no oxides get deeply into the weld pool, the filler metal needs more deoxidizing materials when using the more-active CO2, or when welding on already oxidized base metal; E70S-6 is one such filler.To answer your first question, no, there is no difference between guns used with Argon versus  75/25%  Argon/CO2.If you give more information about which particular piece of equipment you have, it is easier for members here to give you specific answers about it. Lots of variations exist in machines, methods and just about everything else.
Reply:Thanks oldiron2. I have 4 welding plants.My main problems are with a second hand unit i got. It is a 3 phase 440amp welder. The wire feed is a Berion 41Lmag wire feed unit. Im having problems getting consistant welds and i am blaming everything execpt myself!!! im just not getting that crisp sound when welding that I think i should get although the welds are pretty good. I was surprised to see that the wire speed changes when you arc the torch to the material. It seems alot faster then when i just pull the trigger and let the wire out without arking. Also found it strange that the current changes when i change the wire feed. What annoys me is that the wire feed is in the range 1 to 12. nothing about inchs per minute. so everything is pretty much guess work. Inside the wire feed unit there is 2 oter knobs. one appears to be a gas timer and the other seems to be a fine control for the wire speed. Maybe im looking for the impossible but im not getting the crisp sound im looking for, or what i think i hear in everyone elses workshop!  Was welding 3mm wall 50 box today with voltage at 19 to 20 volts. Was giving me 130 amps which seemed to weld nice. I know it is a balancing act with the mig to match voltage and wire speed coreectly but when i noticed the current change today with just changing the wire speed it has added another variable to the mix! I also have a little single phase 220 volt murex tradesmig welder. Nice machine although very hard to get serious power out of it. Its a 250amp machine. Thanks for the help so far! Will keep kicking the welder unitl i  get there!
Reply:I would like to ask a couple of questions, to try and help diagnose your problem. (1) what kind of shielding gas are you using?(2) what shielding gas pressure are you running?(3) are you maintaining a constant arc length and travel angle?I hate to answer a question with a question, but considering what I see some of my students doing I usually do.
Reply:Originally Posted by ericwoodsHi everyone. Just 2 quick questions. Firstly is there a difference between a mag wire feed unit and a mig wire feed unit. I have a mag wire feed connected to my 3 phase mig plant. I noticed that when a pull the trigger on my torch  i get the desired wire feed rate. then when i arc the torch for welding the speed is much quicker? is there 2 speeds? one when not welding and one when you are welding. Also i knoticed that when i change the wire speed not the voltage the current increase and decreases? i thought the current does not change until you change the voltage. Can anyone help me with this? Thanks.
Reply:WIRE MACHINES Attached Images"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by ericwoodsHi everyone. Just 2 quick questions. Firstly is there a difference between a mag wire feed unit and a MIG wire feed unit. I have a mag wire feed connected to my 3 phase MIG plant. I noticed that when a pull the trigger on my torch  i get the desired wire feed rate. then when i arc the torch for welding the speed is much quicker? is there 2 speeds? one when not welding and one when you are welding. Also I noticed that when i change the wire speed not the voltage the current increase and decreases? i thought the current does not change until you change the voltage. Can anyone help me with this? Thanks.