Heat control welding 16 ga stainless

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We make counters and some hoods out of 16 ga SS. Usually type 304. It's a laborious process, mainly because if you aren't careful with the heat, the metal warps - not to mention the burn marks. We have a top-notch Miller Tig welder, we half-lap the corners, we use heat sinks and we air cool. Nevertheless, we still can only weld about an inch at a time.   Are there other processes that we can do that can make this easier and faster? Someone mentioned laser, but I think that the costs may be prohibitive. I'd be very open to some way that we can better localize the heat.
Reply:Plug weld them, stronger than tack and faster for your application.Miller Thunderbolt 225Millermatic 130 XPLincoln HD 100 Forney C-5bt Arc welderPlasma Cutter Gianteach Cut40ACent Machinery Bandsaw Cent Machinery 16Speed Drill PressChicago Electric 130amp tig/90 ArcHobart 190 Mig spoolgun ready
Reply:Without seeing the welding proceedure joint design, and other variables its hard to give an absolute answer. You could start by running pulse tig, maybe a smaller tungsten and smaller filler. Maybe even some pulse mig would work. you should be able to weld way more than one inch at a time. --Gol'
Reply:One thing that you might consider is a resistance spot welder. Very minimal heat will be applied because the weld is instataneous.
Reply:Thanks for the input. I'm talking about an outside corner joint here, so a plug or resistance won't help. Any more thoughts?
Reply:something must be wrong, you definitely should be able to weld more than an inch without warping the thing.what are your machine settings? filler size? tungsten size?  how much tig welding have you done?  Stainless takes alot of practice...
Reply:I weld 25g 304 stainless all day long. And I don't have problems with warp-age. The setup we use is as followsPure Argon @ 25fpmGas Lens with a # 6 cup.Kemppi Tig @ 2sec preflow, 6 sec post.1.6mm Red. ground very very sharpFor open corners requiring filler 24 ampsLap joint 41 ampsand on good tight fittup external corners not needing any filler 30 amps. And you'll have beautiful light straw coloured welds.I've only got this picture, which doesn't show a very good example but it's close Attached Images
Reply:Originally Posted by KrebWe make counters and some hoods out of 16 ga SS. Usually type 304. It's a laborious process, mainly because if you aren't careful with the heat, the metal warps - not to mention the burn marks. We have a top-notch Miller Tig welder, we half-lap the corners, we use heat sinks and we air cool. Nevertheless, we still can only weld about an inch at a time.   Are there other processes that we can do that can make this easier and faster? Someone mentioned laser, but I think that the costs may be prohibitive. I'd be very open to some way that we can better localize the heat.
Reply:Just had a look again at the gauge chart, and I fact it's (0.8mm) 22 gauge not 25 we use.
Reply:Pulse TIG is the first one I would try. Much less heat input, less time at melting temps.I agree with the bodyman comment on the thin stuff like 22ga somewhat. Peening is nothing new. I have learned that when working with thin material, the smaller the tungsten, the better. I use a .040" tungsten on 16ga stainless, and a .045" filler at 37 amps set as max. If I'm doing an autogenous weld(no filler) you can use as little as 25 amps as max.22ga should be proportionately less, so figure in the 20-25 amp range at most.If oyu really have a top-notch miller tig, the pulse feature has alot of options and should serve your needs well.The settings above are non-pulse settings. Pulsing requires slightly more amps, because it is on short bursts.Most sanitary stuff is no filler, so 20amps should do the job.Make sure not to forget about welding direction and techniques to minimize distortion.You must keep the tungsten as close as possible to focus the heat better and increase travel speed.Laser may be cost-prohibitive, but have you considered plasma arc welding?Best of luck.
Reply:Also try a gel heat sink, we have some stuff from kimball midwest, its a spray on gel that acts like a really good heat sink.  I use it on square tube joints to keep them from pulling.  It works really well and cleans up easily with water.Have we all gone mad?
Reply:Thanks for the feedback. Man, I really strugle at anything lighter than 18 gauge. kudos for the 22 ga work Shocks dr.Question: Our equipment is all transformer type. Would the variable frequency and additional waveform control of an inverter unit be of significant help?
Reply:Originally Posted by KrebThanks for the feedback. Man, I really strugle at anything lighter than 18 gauge. kudos for the 22 ga work Shocks dr.Question: Our equipment is all transformer type. Would the variable frequency and additional waveform control of an inverter unit be of significant help?