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Welding/SS Pipe Welding in a 6-G position


We are looking to certify a few welders on our crew in SS Pipe. We will be testing on a 2" sch. 160 304L pipe in a 6-G position.We have to weld pipe sizes from 2-12" sch 10-40 on the job.My question is what process to use on a job like this MIG TIG Stick. We attempted MIG with the thought it would be quicker and easier for some of the guys but found it to be the most difficult.A couple of us a very good with TIG and one guy has passed a 6-g test with stick on steel pipe. Any input would be great before we pick the process to certify on. Thanks Art

Often what process is used for what size of pipe is specified by the systems engineer.
The general rule is 4" and larger is stick welded, under is TIG.
However on stainless steel the weld quality with TIG is so much better that it is often used for all sizes.
If time constraints won't allow TIG on larger pipe, you have Stick, MIG, Dual-shield or inner shield to pick from.
Of the faster processes, Dual-shield yields the better welds.
MIG requires the use of tri-mix gasses (either Helium-Argon-CO2 or Oxygen-Argon-CO2), Dual-shield does not.
The problem with stainless wire feed processes, and Stick, is that you have to run higher heat to overcome the poor conductivity of the stainless wire. This can conflict with stainless steel's lower meting point than carbon steel.
With TIG the stainless is not conducting your welding current so you actually use lower heat than for carbon steel.
No matter what you choose you will need to run some test welds to see what works best for your crew.
I have never loved stainless stick welding.

Be careful of over-use of 309L filler.
People tend to grab it because it sticks to anything, but if you weld it too hot and fast you can get horrific cracking problems.
308L, 321, and 347 aren't as problematic as 309L, as far as cracking goes.
321 and 347 are just heat stabilized versions of 308L.


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Ernie Leimkuhler


Questions about Oxy-Acetylene welding/cutting, MIG, TIG, Flux-core, Stick welding, brazing and soldering, bike frames, air frames, motorcycle frames, structural welding. Also questions about Welding Certifications and Inspections. All questions about fabrication of metals (stainless steel, steel , aluminum, brass, bronze, copper). Basic questions about underwater welding. TIG is my strongest subject.


Extensive background in most welding fields. 18 years fabrication of metal theatre scenery, 16 years structural steel, 2 years pipe welding, 9 years as a Welding Instructor at South Seattle Community College, and 5.5 years as a Welding Instructor at the Divers Institute of Technology. 16 years Industrial Welding Consultant for fabrication shops in the greater Seattle Area. 11 years Architectural Metal Fabrication. 8 years in Film/TV; SPFX/construction/set-deco/props/. 33 years Blacksmithing and Knifemaking. Currently a Field Welding Inspector for Otto Rosenau and Associates.

American Welding Society - Certified Welding Inspector Washington Assoc of Building Officials (WABO) - Special Inspector - Structural and Reinforcing Steel.

Do a search on google groups for "Ernie Leimkuhler" in the rec.crafts.metalworking and sci.engr.joining.welding groups. Blacksmith's Gazzette - Anvil Making

BA Theatre Technology - Purdue University.

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