How to weld SS 304 cooling pipes

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I'm welding this tank\mixer which has cooling ribs all around it. The tanks body is SS 304 8mm, the cooling ribs are SS 304 3mm. (pipes cut in half and tacked to the mixers body)I'm welding at 170A with a 2.4mm 2% Thoriated tungsten, #7 gas lens, pure Ar, 10LPM and a 2.4mm 316L filler rod.The bead itself is about 7~8mm wide.Does this look like a good bead? this needs to hold 3~5 bar of cooling water.(BTW, i'm welding about 200m on this project.....)Last edited by Rubberduck; 02-18-2014 at 02:49 PM.
Reply:From my phone it looks good. 308L is usually the preferred filler for 304ssAirco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:?No sanding prep on the SS? No final wipe down with lacquer thinnner/acetone,since the mill markings are still visible?Long, long stringers can induce distortion.Is there any plan for sequentially welding to limit distortion?Blackbird
Reply:sure it aint 312 stainless
Reply:I seriously doubt the pipe is 312. 312 is a high-strength alloy used mainly as filler metal but I have never seen pipe made from it. I am also wondering why 316 is being used as filler on 304 pipe.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:Originally Posted by Silicon-based      I seriously doubt the pipe is 312. John
Reply:Originally Posted by dave powelson.....umm the mill markings not wiped off say otherwise, John.Just scroll uP to the pics, please.rubberducky--since you're building a 'not-cheap' pressure vessel, is thereany defined welding criteria specified or is this literally just aseat of the pants, make pretty welds, fluff job??
Reply:Originally Posted by dave powelson?No sanding prep on the SS? No final wipe down with lacquer thinnner/acetone,since the mill markings are still visible?Long, long stringers can induce distortion.Is there any plan for sequentially welding to limit distortion?
Reply:Originally Posted by pat hsure it aint 312 stainless
Reply:Originally Posted by dave powelson.....umm the mill markings not wiped off say otherwise, John.Just scroll uP to the pics, please.rubberducky--since you're building a 'not-cheap' pressure vessel, is thereany defined welding criteria specified or is this literally just aseat of the pants, make pretty welds, fluff job??
Reply:Originally Posted by Silicon-basedI seriously doubt the pipe is 312. 312 is a high-strength alloy used mainly as filler metal but I have never seen pipe made from it. I am also wondering why 316 is being used as filler on 304 pipe.John
Reply:The weld geometry is subject to crevice corrosion. Seeing also that those half-pipes will be under pressure (3-5 bar), these fillet welds wouldn't be my first choice of doing this. What do the plans call for?And +1 on the 308L, however this shouldn't really cause any concern
Reply:Originally Posted by kingneroThe weld geometry is subject to crevice corrosion. Seeing also that those half-pipes will be under pressure (3-5 bar), these fillet welds wouldn't be my first choice of doing this. What do the plans call for?And +1 on the 308L, however this shouldn't really cause any concern
Reply:depending on a number of things, I'd prefer full pen welds with back purging.What you do might perfectly be acceptable, again, we don't know enough details about among others the intended use, the kind of cooling water and the number of cycles this thing will see.