Hello Forum,
I'm exploring the TIG (AC exclusively at this time) PULSEd wave impact on weld joints. If I rely on my own experiments? I'll end up spending my entire existence trying different wave forms' combinations then DIE~~ before there's much of a pattern resulting.
However, if the Forum will feed back, will take time to define, with detail, what worked where and with what settings? there's a better chance of all of us getting a better picture of different applications of TIG Pulsed Wave (forms) in various applications and we might even..... be able to make a few Rules of Thumb to share with others about the subject.
YES.... there are plenty of welders who still use transformer power supplies that only deliver 60Hz (+ or minus) frequency and have no control over the EN/EP balance. Those power supplies have no way to automatically surge the amperage during their welds. OK fine; that works fine if you're skilled enough to employ those power supplies for your work scope. But I'd like to discuss the inverters with pulsed TIG amperage controls, and to more fully understand the overall experience of pulsed TIG.
I'd like to see a more comprehensive discussion about pulsed TIG as it applies to AC aluminum (specifically) and non-robotic TIG welding.
6061.com, a utube contributor and excellent welder, has shown a few pulse methods that are somewhat divergent from Jody's 33 method. I've been trying variations of both methods (limited to the Miller Dynasty 300DX) and found a world of welds I didn't know existed..... ?
If the Forum had time, and was interest? I'd welcome reports on your use of the two methods (6061's short duration high amperage 'spike' vs 1/3 over 2/3 intervals as Jody Collier has shown) I've tried both as well as other pulsed AC TIG and would like to have a wider knowledge base - compared to doing all the experiments one off.
Thanks for any suggests, reports, and the details of the settings with all the weld conditions listed.
Cheers
Kevin Morin
Kenai, AK
Oscar,
in one or two of 6061's videos he uses a very short (compared to most others' settings) high pulse time. For example a period of 1.2 or 1.3 pulses per second and only 10-15% high then a back ground that is 20-30% of the peak. The wave form in regard the weld wattage output is sharp, short up &down and the background for 80+ % of the period.
While not always showing his dip rod/filler insertion as clearly as Jody's welding videos- it appears he's adding rod just before the peak pulse. So the rod seems to bulge the puddle a bit- and then get flooded into the deeper penetration by the short high peak power. 6061 also shows this welding method without filler by lapping and outside corner fillet so one piece is 30-to-50% overlapping the part it will be joined to.
My experiments with this method, which differs from the 33% and 67% back ground, by what amounts to fairly small percentage of peak wattage duration, have shown me that the final beads may look similar in appearance - but there seems to be more penetration (?) - especially on outside corner fillets? However the peak's being shorter means the output peak has to be higher amperage since the net RMS is lower with this more 'saw tooth' pulse pattern.
Reading some of the articles linked and referenced in other threads, here, it seems there was considerable 'stirring' of the alloys in the puddle while there was higher and higher frequency - this was pulsed DC. So, I'm interested in learning if a pulsed AC Tig weld would have greater break bend performance- if there was a combined surge/pulse of welding current while modulating the AC at 200 or greater Hz? IF someone has already done this type of contrast I haven't found the link anywhere, and would appreciate anyone's help locating more on the subject.
What kind of uniform test fixture would be the most reliable to break/bend coupons? Link the U bending fixture for pipe coupons? I've usually only bent the welded parts in a vise with a Crescent wrench- but that seems random in many aspects? Jody usually stops at the cut/polish/etch stage looking at penetration. That is helpful, but the failure in bending seems a more reliable indicator of a gain or comparison of load strength in the various joints. T-fillet, outside corner, butt (plain uniform edges, single bevel edges, and double bevel edges) and lap joints.
Hope that describes what the wave/pulse pattern 6061 was showing, and of course it would be interesting to see the other patterns of surge/pulses where peak surge time and background are equal, as well.
Cheers,
Kevin Morin
Kenai, AK
in one or two of 6061's videos he uses a very short (compared to most others' settings) high pulse time. For example a period of 1.2 or 1.3 pulses per second and only 10-15% high then a back ground that is 20-30% of the peak. The wave form in regard the weld wattage output is sharp, short up &down and the background for 80+ % of the period.
While not always showing his dip rod/filler insertion as clearly as Jody's welding videos- it appears he's adding rod just before the peak pulse. So the rod seems to bulge the puddle a bit- and then get flooded into the deeper penetration by the short high peak power. 6061 also shows this welding method without filler by lapping and outside corner fillet so one piece is 30-to-50% overlapping the part it will be joined to.
My experiments with this method, which differs from the 33% and 67% back ground, by what amounts to fairly small percentage of peak wattage duration, have shown me that the final beads may look similar in appearance - but there seems to be more penetration (?) - especially on outside corner fillets? However the peak's being shorter means the output peak has to be higher amperage since the net RMS is lower with this more 'saw tooth' pulse pattern.
Reading some of the articles linked and referenced in other threads, here, it seems there was considerable 'stirring' of the alloys in the puddle while there was higher and higher frequency - this was pulsed DC. So, I'm interested in learning if a pulsed AC Tig weld would have greater break bend performance- if there was a combined surge/pulse of welding current while modulating the AC at 200 or greater Hz? IF someone has already done this type of contrast I haven't found the link anywhere, and would appreciate anyone's help locating more on the subject.
What kind of uniform test fixture would be the most reliable to break/bend coupons? Link the U bending fixture for pipe coupons? I've usually only bent the welded parts in a vise with a Crescent wrench- but that seems random in many aspects? Jody usually stops at the cut/polish/etch stage looking at penetration. That is helpful, but the failure in bending seems a more reliable indicator of a gain or comparison of load strength in the various joints. T-fillet, outside corner, butt (plain uniform edges, single bevel edges, and double bevel edges) and lap joints.
Hope that describes what the wave/pulse pattern 6061 was showing, and of course it would be interesting to see the other patterns of surge/pulses where peak surge time and background are equal, as well.
Cheers,
Kevin Morin
Kenai, AK
I've used a slow pulse occasionally on particularly thick AL if it is being stubborn. Seems to help move the puddle and prevent filler rod burnback a bit when I'm having to use higher amperages and if the base metal is a bit dirty to begin with. Mostly only above 300A, and the pulse settings would be approximately 70% background, 50% on time, and 1.2pps. It also seems to sometimes help prevent the puddle from "horshoeing" around the root. The pulse hits, and it will flow right into the root.
Has worked well for me, but I'm fairly new to the thick AL game, so take it with a grain of salt.
Has worked well for me, but I'm fairly new to the thick AL game, so take it with a grain of salt.
What you're asking for I cannot assist with, and most would not either. I just checked your machine's spec's and it is capable of producing that pulsing characteristic, so why not just send sample couples to be tested for you? I thought it was going to be something not available to your machine, but it is more than capable of producing the pulse pattern for you.kmorin wrote:So, I'm interested in learning if a pulsed AC Tig weld would have greater break bend performance- if there was a combined surge/pulse of welding current while modulating the AC at 200 or greater Hz?
Cheers,
Kevin Morin
Kenai, AK
As for frequency, higher than 200Hz serves little purpose in high-amperage welding, IMO. From what I gather, too high of a frequency severely limit the total heat being put into a part. At 1.3 PPS, 10% on-time @ peak equates to 77ms of peak current. So then another variable to look at is: how many AC periods @ peak current do you want to squeeze into those 77ms? At 20Hz you can squeeze 1.54 periods, at 200Hz, you can squeeze 15.4 periods, and at the 250Hz limit of your machine you can squeeze 19.25 periods into 77ms of peak on-time. What your asking for is not unattainable, it just requires a lot of time, money, and a very controlled, systematic methodology to produce repeatable results among a variety of sample pieces whose average values must be evaluated compared to just testing a single piece. It's the kind of stuff that I imagine welding/mechanical engineers get paid BIG bucks to do. Good luck with your inquiry.
Thanks for time to read and reply Oscar,
I can see from your remarks the level of effort needed will not be something Jody could really capture in a video about the subject. But, maybe a single 3 point test series might be something worth considering?
My work load is too full to take time off to make the tests over the spread of variables so I'll just rely on 'what's working now' and keep using those methods.
Cheers,
Kevin Morin
Kenai, AK
I can see from your remarks the level of effort needed will not be something Jody could really capture in a video about the subject. But, maybe a single 3 point test series might be something worth considering?
My work load is too full to take time off to make the tests over the spread of variables so I'll just rely on 'what's working now' and keep using those methods.
Cheers,
Kevin Morin
Kenai, AK
BillE.Dee
- BillE.Dee
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Weldmonger
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Posts:
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Joined:Mon Nov 27, 2017 8:53 pm
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Location:Pennsylvania (Northeast corner)
Kenai, Jody did test using settings for pulsed welding of aluminum. Cut and etch showed considerable penetration as compared to other ac welding using wave forms advanced square, soft square, triangle and sine and advanced pulsed. Perhaps that video will help you out. I don't know how to attach stuff or I would..sorry.
For Jody to consider? Good luck with that as he doesn't actively participate in these forums. I've noticed that a lot of his videos are "repeats" to a certain extent, because (i'm pretty sure) it's just way easier to re-cover older topics, perhaps in a new light or a new scenario, than to engage in a more R&D type of welding exploration. If your plate is full, I'm sure his is just as fullkmorin wrote:.. might be something worth considering?
BillE.Dee wrote:Kenai, Jody did test using settings for pulsed welding of aluminum. Cut and etch showed considerable penetration as compared to other ac welding using wave forms advanced square, soft square, triangle and sine and advanced pulsed. Perhaps that video will help you out. I don't know how to attach stuff or I would..sorry.
BillE.Dee, that video was a bit different because it was a "hybrid" pulsing function that "injected" a DCEN component into the mix, which I think is a great feature, but it changes the scenario altogether (because
kmorin's 300dx and the vast majority of AC/DC TIG welders do not have this function at all).