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Up Topic Welding Industry / General Welding Discussion / common practices for thin-guage stainless TIG (GTAW)
- - By sriesch (*) Date 07-21-2009 18:32
Is it common in the welding industry to TIG weld thin-guage stainless steel without using pulse, a chill plate, or backing gas?  Perhaps this is not even a valid question and the answer is "it depends", but just in case there is an overwhelming yes/no answer, I thought I would ask.

The reason I ask is I am practicing various welding processes in my spare time while job hunting, and while obviously more practice in anything is better and I would love to concentrate on every single aspect of every single process, I have limited class time and would like to concentrate on aspects that I am more likely to encounter (without yet knowing where I'm likely to be working).  I'm not sure if it is the best use of time to try to get a long series of perfect thin-guage stainlesss weld this way or if the typical employer would just hand me a chill plate or use pulse and I'm mostly wasting my time.  However I don't want to practice always using pulse for example and then be hired on and given a machine with no pulser and have to try to learn how to do without there instead of now.

Thoughts?  Thanks in advance for your time.
Parent - By Lawrence (*****) Date 07-21-2009 18:49 Edited 07-21-2009 18:51
Pulse GTAW is not commonly used in manual welding of thin stainless  (I"m sure there are exeptions and folks who may disagree)  In my opinion there are a few joint types that can benefit from pulsed GTAW in production, but for the most part, pulsation for manual GTAW is just a costly option that sales folks pad their pockets with.

If burn thru is cause for rejection than argon backups and heat sink tools will be required...

But you sound like your just looking for things to practice in order to have the best skills you might possibly bring to a job.

Thin stainless fillets or thin to thick fillets are excellent practice... But in my opinion for the beginner this excercise can also be done with plain carbon steel sheet.

Controling heat input and minimizing burnthru on thin fillets is great practice no matter what the base metal.. Torch angle, wire feed technique, surface prep, electrode prep... all are very similar whether stainless or plain carbon steel...  There are differences of course in thermal conductivity and distortion control, but for just learning how to control your power supply you will be fine.

If you do have access to stainless,  With good sheared flat pieces you shoud be able to do a thin to thin (0.040) fillet with no burn thru after a bit of practice.. without backing gas or heat sinks....  Production work will almost always go better with backing and heat sinks, but they are not always available.

If you can do it without a heat sink... life will become all that much easier when one becomes available.

When backing gas is and is not required is a pretty big subject in itself.
Parent - By Metarinka (****) Date 07-23-2009 02:50
I worked for awhile as a sheet metal welder almost exclusively on stainless steel via GTAW, I can never once remember using a pulse setting.

Generally we welded around 16-20 ga but on occasion work as thin as 24-28 came through.

backing and back purging generally were not considered due to the cost and complexity, it's assumed if you performing autogeneous welds on sheet metal than they are not considered a load bearing structure so quality requirements are different.  However under certain circumstances back purging and chill bars will employed mainly on thick to thin sections or difficult areas where melt-thru occurred.

in terms of practical experience with welding on thin gauge stainless. In general the preferred positions were vertical down, flat and horizontal, with vertical down being the easiest. Torch angle is extreme maybe with the torch being 10-15 degrees from parallel with the plate. Any more and the penetration will cause severe melt thru. Also the metal required tacking ever 3-6 inches depending on your skill and situation
Parent - By sriesch (*) Date 07-24-2009 18:21
Thanks for the info!  I will plan on doing extra practice in this area after all.
Up Topic Welding Industry / General Welding Discussion / common practices for thin-guage stainless TIG (GTAW)

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