when to choose Pulse over CV spray arc? (usually 6-12mm mild steel)

[w124]

i do have my "own" unit at my work place, its 500A CV.
i can see the benefits of pulsed arc when it gets to weld a lot of thicker aluminum (i mean 6-8mm), and thats the only material im pulsing recently, because i dont see many benefits of welding with pulse steel starting from 5-6mm up to 12mm. maybe at 12mm it doesnt make that much difference but the thinner it is, i think spray arc is a lot better.
first and the most important, penetration - as good as pulse.
time to weld an item, if its 6mm thick i can weld 2 items and starting third at the time someone who's pulsing finishing the first one. why is that important? i can do what i want when i finish earlier and still getting paid for doing nothing instead of breathing the fumes.
good appearance, spatter free except some poor starts at rusted plates but same with pulse.
i can enjoy the songs played on the radio with that magnificent sound of spray arc (even on rusty steel) in the background - instead of that annoying buzz, lol.

haven't tried pulse for out of position welding, but once had to fill a quite big gap in 1G position and pulse has done a great job, doing it in one hit but slow, looked like there was no gap.

also it provides more heat input on the work piece (as the whole process takes more time than spray? at least from my experience with it), so i want to hear your opinions.

 

[matt1978]

Firstly, Pulse was never intended to compete with Spray arc on thicker material. It was invented to overcome to the Transistion/mixed arcing phase whereby on a conventional machine the material thickness requires too much voltage to remain in Dip transfer but not enough to get into a true spray arc. Depending on your wire diameter this material range is anything around 3-6mm.

The main advantage of Pulse aside from being virtually spatter free across all material thickness ranges is it’s ability to weld a huge range of material thickness with just one wire diameter.

Generally Pulse welding on Steel around 10mm upwards will usually always be slower than Spray, as you have found out. This is because of the way Pulse works, with it’s one droplet per Pulse cycle, after the droplet, there is no further material detached across the arc until the next Pulse cycle. Whereas with Spray you have lots of little detachments happening almost constantly.

However things have moved on, Lorch as an example, has things such as SpeedPulse-XT which is a modified Pulse arc that keeps all of the known benefits of Pulse but with a much higher deposition rate and welding speed often in excess of what can be achieved with convention solid wire with Spray arc and certainly by far much deeper penetration. There are even now modified versions of Spray arc, Lorch has SpeedArc XT, EWM has ForceArc and there are many others available, which again gives deposition and travel speeds way in advance of any conventional CV machine.

Bringing it back into the original topic of standard Pulse v Standard Spray however there are a couple of points where Pulse does have a big advantage.

It’s not quite true that in Steel that Spray offers the same level of penetration, by its nature, Spray arc spreads the power/heat over a comparably wide area, so the penetration tends to be wide but shallow, where as with Pulse (even standard Pulse) you get a “finger tip” style of penetration which tends to be narrower and deeper. Other benefits such as in Aluminium you get less porosity, can weld 1.5mm thick plate with a 1.2mm wire which is cheaper to buy and by far easier to feed and on Stainless Steels, you can put less heat in which helps to achieve nicer colouring.

If your interested if you look into the Lorch section of this forum you will see some high speed videos comparing the different arcing phases, which will be especially good to visually see why Standard Pulse is definitely considered slower on steel against Spray arc

 

[Brad93]

Probably the most concise yet detailed explanation of pulse benefits I've ever read.

As a Lorch S3 owner I can say the uses you find for using pulse on steel never cease to impress. Overhead welding, vertical welding, welding around round or oddly shaped parts with the arc length correction. Lorch's SpeedPulse and SpeedArc XT is worth every penny.

 

[backpurge]

Firstly, Pulse was never intended to compete with Spray arc on thicker material. It was invented to overcome to the Transistion/mixed arcing phase whereby on a conventional machine the material thickness requires too much voltage to remain in Dip transfer but not enough to get into a true spray arc. Depending on your wire diameter this material range is anything around 3-6mm.

The main advantage of Pulse aside from being virtually spatter free across all material thickness ranges is it’s ability to weld a huge range of material thickness with just one wire diameter.

Generally Pulse welding on Steel around 10mm upwards will usually always be slower than Spray, as you have found out. This is because of the way Pulse works, with it’s one droplet per Pulse cycle, after the droplet, there is no further material detached across the arc until the next Pulse cycle. Whereas with Spray you have lots of little detachments happening almost constantly.

However things have moved on, Lorch as an example, has things such as SpeedPulse-XT which is a modified Pulse arc that keeps all of the known benefits of Pulse but with a much higher deposition rate and welding speed often in excess of what can be achieved with convention solid wire with Spray arc and certainly by far much deeper penetration. There are even now modified versions of Spray arc, Lorch has SpeedArc XT, EWM has ForceArc and there are many others available, which again gives deposition and travel speeds way in advance of any conventional CV machine.

Bringing it back into the original topic of standard Pulse v Standard Spray however there are a couple of points where Pulse does have a big advantage.

It’s not quite true that in Steel that Spray offers the same level of penetration, by its nature, Spray arc spreads the power/heat over a comparably wide area, so the penetration tends to be wide but shallow, where as with Pulse (even standard Pulse) you get a “finger tip” style of penetration which tends to be narrower and deeper. Other benefits such as in Aluminium you get less porosity, can weld 1.5mm thick plate with a 1.2mm wire which is cheaper to buy and by far easier to feed and on Stainless Steels, you can put less heat in which helps to achieve nicer colouring.

If your interested if you look into the Lorch section of this forum you will see some high speed videos comparing the different arcing phases, which will be especially good to visually see why Standard Pulse is definitely considered slower on steel against Spray arc

Very well worded Matt, an excellent explanation

 

[w124]

"on a conventional machine the material thickness requires too much voltage to remain in Dip transfer but not enough to get into a true spray arc. Depending on your wire diameter this material range is anything around 3-6mm."

i've been using globular transfer probably one year ago to weld 4-6mm, but it was absurd to use a pneumatic hammer to get rid of spatter.
since then i have learned a lot more about spray and how to set it properly.
i saw those videos from Lorch, but when i ask people from my region i hear that standard CV with solid wire or dualshield is the most used for manufacturing.

as for the penetration, never checked it for fillet welds as i didnt had any dye penetrant in my hands. and never worked anywhere where the welds were checked. well, im not even certified.
so the only way to tell is by what i can see throught the screen while welding or looking from the other side if it creates a slight hump (only works for material up to 5-6mm i believe) 8mm just drops off the mill scale but i dont say its a good method to tell how far it penetrated ;p.
and the gas of my choice is always Argon- 5%Oxygen

some welding from today its 5mm, 30V and a little more than 12m/min 1,0 wire


and some other on nearly the same voltage (+1/1.5) and WFS on 10mm but slower travel speed


ill try pulse for out of position welding if i get some time, and overhead spray.

 

[Brad93]

"on a conventional machine the material thickness requires too much voltage to remain in Dip transfer but not enough to get into a true spray arc. Depending on your wire diameter this material range is anything around 3-6mm."

i've been using globular transfer probably one year ago to weld 4-6mm, but it was absurd to use a pneumatic hammer to get rid of spatter.
since then i have learned a lot more about spray and how to set it properly.
i saw those videos from Lorch, but when i ask people from my region i hear that standard CV with solid wire or dualshield is the most used for manufacturing.
No what it is is half the welders out there have not been properly trained and have never heard of spray transfer. There’s tonnes of areas it should be used but the welders don’t have the skill to select the right parameters. Spatter is mostly a problem caused by incorrect parameters and setup due to lack of welder training or due to equipment not being maintained.

as for the penetration, never checked it for fillet welds as i didnt had any dye penetrant in my hands. and never worked anywhere where the welds were checked.
Sorry mate but you’re talking completely out of your **** there. Dye penetrant is for inspecting welds for small surface discontinuities such as cracks, LOF at toes, pinholes, porosity etc.
Macro Etching is used to see the penetration profile of a weld.

well, im not even certified.
so the only way to tell is by what i can see throught the screen while welding or looking from the other side if it creates a slight hump (only works for material up to 5-6mm i believe) 8mm just drops off the mill scale but i dont say its a good method to tell how far it penetrated ;p.
and the gas of my choice is always Argon- 5%Oxygen
If you’re penetrating all the way through 5-6mm your welding far too hot and probably ruining the weld metal properties. There is very little need for penetration all the way through a filler joint in that material thickness.
That gas is M14ArCO-5/2 like Cougar 5 or Argoshield Light. So only any good for up to 6-8mm material really.

 

[w124]

Macro Etching is used to see the penetration profile of a weld.
thats what i meant, not that red liquid that i described.

If you’re penetrating all the way through 5-6mm your welding far too hot and probably ruining the weld metal properties. There is very little need for penetration all the way through a filler joint in that material thickness.
That gas is M14ArCO-5/2 like Cougar 5 or Argoshield Light. So only any good for up to 6-8mm material really.

so i assume -5V would be ok but when theres a lot of welding for a relative small item (something like 2m of weld on 6-7 pieces all made from one 1x1m 5mm sheet, and all welded from both sides then the heat input will be still very high.

i havent used ar18co2 for a long time but if its better then ill switch from omix

 

[Brad93]

I can’t say I’m not the one who should be working to a fab drawing or WPS.

 

[Sarto]

What could be a starting value for wire feed speed, volts and gas mixture and flow to enter in the
spray world? (At what kind of amperes could the machine be working?)
Are there other "tricks" like wire stickout or other that I don't know?

Machine is a big old 400 amp 3 phase, wire is 1mm or 1,2mm (don't remember now). Pieces are mild steel 10mm thick.

In the factory I work they never seem to weld in spray mode. Maybe I could persuade them to try.

Thanks to all.

Sart0

 

[Brad93]

1mm wire will go into spray around 27V, 200 amps, about 9m/min.

1.2mm wire will go about 8m/min, 28v. These figures are for argoshield universal/heavy

 

[Sarto]

@Brad93
Thanks for the informations.

 

[henry Kadzielski]

Just my two cents worth. When I did my mig ticket, we were welding 12mm plates and using 'argo shield light' otherwise refered to as 52 (93%Ar 5%o2 2%Co2) I think that was the breakup, but 52 nevertheless. The entire college welding department was run on it. Several of the students asked ' if we are welding thicker plates why are we using 'argo shield light'. The reply was 'it doesn't make any difference to the result. As a result that is why I am using it for everything I am doing. Just my two cents

 

[Brad93]

Just my two cents worth. When I did my mig ticket, we were welding 12mm plates and using 'argo shield light' otherwise refered to as 52 (93%Ar 5%o2 2%Co2) I think that was the breakup, but 52 nevertheless. The entire college welding department was run on it. Several of the students asked ' if we are welding thicker plates why are we using 'argo shield light'. The reply was 'it doesn't make any difference to the result. As a result that is why I am using it for everything I am doing. Just my two cents

You can weld thicker material with Argoshield light. But if you want the right penetration with good mechanicals you need to go to heavier gas usually.
5/2 would be Argoshield light here.

This is a small insight from BOC citing the reasons for heavier gases.
https://www.boconline.co.uk/interne...-Shielding-and-Fuel-Gases410_115458.pdf?v=3.0

 

[Brad93]

https://www.boconlineshop.com/wcsst...downloads/shielding-gas-brochure410_80125.pdf

 

[w124]

i've been working earlier as a fitter on heavier constructions, and none factory used OMIX, but 18% CO2. so it makes a lot of sense now.
thing that got me into OMIX was insanely smooth arc. when i empty the cylinder ill get an CO2 mix and see how it works. also on this occasion it would be nice if our driver would bring the stuff for macro etching.

 

[Brad93]

i've been working earlier as a fitter on heavier constructions, and none factory used OMIX, but 18% CO2. so it makes a lot of sense now.
thing that got me into OMIX was insanely smooth arc. when i empty the cylinder ill get an CO2 mix and see how it works. also on this occasion it would be nice if our driver would bring the stuff for macro etching.

As you're in Europe you guys work to slightly different gas mixtures than us here. M20ArC-8% is common, M20ArC-20% is very common. Trimix is slightly unusual in Europe I suppose.