16ga 304 stainless warping

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I am currently doing some cosmetic pieces , Im using 16 ga. 304 stainless, I'm working on a ceiling beam overlay , its curved so I cant just break it , it needs be welded ,, I am using a tig machine , but having problems with the main piece warping during welding , I have it clamped flat to my welding table , but I am still getting excessive warping ,, is there any way to eliminate this problem?I'm using a Thermal Arc 110 v machine running at about 40 amps  i have to tack it on the inside because the piece is so long 17' long 8''wide  with 7" tall sides then Im welding the edge all the way down ,rounding the edge ,  then finishing it with a #4 grain ,,,  were trying to make it look like a solid beam ,, when its installed ,  also we are plasma cutting the curved piece out of a sheet , no warping from the cutting ,Last edited by ariznitro; 12-05-2010 at 10:31 PM.Reason: to give more information
Reply:Rapid pulsing and faster movement.You don't mention the machine you're using, but if it doesn't have pulse capability, faster movement is your only option.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Only other option is to spread tack welds all over the piece, and backfill alternating areas. It's still going to be grumpy, but it will lessen the issue. No easy way to heat it up to allow for less thermal reaction..... raw flame on ss is not good, it will add some carbon, and keeping the heat even is difficult to say the least.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.


Reply:I agree with sundown. Stainless that thin, you need to keep you travel speed up fast. Are your welds colorfull or a dull gray?Ya gotta spend money to make money!
Reply:the tacks are colorful but the outside final welds are all a dull grey
Reply:A very challenging weld.  In an ideal situation, this weld would be have a tight fitting consistent precise joint fitup, small tack welds would be made every few inches to maintain fitup, tight fitting copper heat sinks on the backside of the joint and adjacent to the joint on the top side, arc lenght would be held very tight and constant, pulsing would be used to minimize heat input, amperage would be balanced with travel speed to allow the fastet possible travel speed in order to minimize heat conduction into the base metal.Since it is diffcult to travel fast and precise for any distance when hand welding, it may be best to try small weld segments that you can make very fast with minimal heat input.  At the extreme of this approach would be very short duration/high current spot welds, that you would allow to cool before continuing with the next overlapping spot.
Reply:Pretty much like any sheet metal, you need to minimize the heat input and overall temperature rise in order to reduce and minimize warping.Chill-blocks or heat sinks on the back side and/or adjacent to the welding zone, faster travel speed, possibly pulsing, skip-weld and back-step, lots of small well-fused 'tacks' spread out all over the seam that then get slowly filled in until the seam is fully welded, pausing and letting the sheet metal cool off before continuing to weld a little bit more, that sort of thing.Trying to run a 'continuous' weld bead all along, even after the seam is tacked, will just warp it all.  The best laid schemes ... Gang oft agley ...
Reply:thanks guys , all the help is greatly appreciated , fished product came out really nice , I would like to thank all you guys for your help ,, I really really appreciate it ,, thanks a ton ,, here's a picture of the finished part installed  again thanks for all your help,, this site is awesome .

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Originally Posted by ariznitro

thanks guys , all the help is greatly appreciated , fished product came out really nice , I would like to thank all you guys for your help ,, I really really appreciate it ,, thanks a ton ,, here's a picture of the finished part installed  again thanks for all your help,, this site is awesome .
Reply:When I worked at a stainless shop, we tigged down to 22ga. and up to 10ga on average. We controlled the heat by doing a weld bead and then cooling the weld. Seemed to work well on the sinks me made. The sinks  and counters for the cruise ships were up to 20 feet long.
Reply:Moved to start separate thread. Sorry.Last edited by 3dbmcg; 2 Weeks Ago at 10:06 AM.Reason: Wrong thread, sorry