In trying to set the parameters on my GMAW power source , I'm not sure what sound I am after in trying to get a spray transfer on steel , if I set the machine to higher ranges and leave the wire speed at a range that would produce a "dip" at lower ranges , I get a popping sound. I can see the wire burning off before it reaches the puddle in small droplets .It does however form a fluid puddle and seems to "wet out" well . I am using .035 wire and C-25 gas for now but may go to an Ar. / Ox mix .
Our WPS for GMAW-Spray Transfer stipulates an Argon/Oxygen mix with no more than 5% Oxygen to achieve a true Spray Transfer. The sound is more of an electrical "HUM" with little or no "Popping". Occasionally, "Popping occurs when passing over light rust or other contaminants in the joint. Hope this is helpful.
Ar/15-20% CO2 mix should be OK for spray transfer or shortarc I use 20% CO2 its hotter than 15% with no troubles you should be assured of spray with .035 wire at 27 V and wire feed around 420 in/min (220A) or more
Reduce parameters as Ar% increases; 2% Oxy should attain spray around 25 V and something around 200A or less I am not precisely sure but should be ample parameters (I dont work with Ar/O2)
Dont attempt 75Ar/25CO2 with .035 wire for spray... 20%CO2 will define the word "NICE" (the 5% _IS_ critical)
you are using wrong gas
20-40A and 2-6V less would likely put you into globular note the spatter pattern is different than short arc- spray is almost perfectly clean near 99&44/100% spatter free
Why use expensive and hard to mix gas as 2 to 4% Oxy? You need to ask for cert sheet for it. I have the impression the CO2 works just as well perhaps better (broader penetration profile) and there is greater tolerance for error in the (20% or less CO2) mix; if you aim at 18% Ar and there is a 2% +/- error you can still weld fine but not so with 3%O2.
regards
D
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