..very true I take my tig finger for granted....love it!Markus wrote:Great to hear that you have improved your skills and interested to test new things
Personally I don't like doing little circles on thing walled pipe.
- It's slower
- It easily create too much heat and you end up with concavity
- It usually create rougher bead inside
Do you have TIG-finger? It's very useful on stainless pipes like these. With TIG-finger you can slide you hand more steady than normally and create constant penetration.
I weld stainless, stainless and more stainless...Food Industry, sanitary process piping, vessels, whatever is needed, I like to make stuff.
ASME IX, AWS 17.1, D1.1
Instagram #RNHFAB
ASME IX, AWS 17.1, D1.1
Instagram #RNHFAB
No, I don't have a TIG finger but should really get one.Markus wrote:Great to hear that you have improved your skills and interested to test new things
Personally I don't like doing little circles on thing walled pipe.
- It's slower
- It easily create too much heat and you end up with concavity
- It usually create rougher bead inside
Do you have TIG-finger? It's very useful on stainless pipes like these. With TIG-finger you can slide you hand more steady than normally and create constant penetration.
I played around yesterday with settings and found that when I run pulse at 2x/second at 55 amps or no pulse at 43-45 amps with faster travel speed the weld comes out gray with no color (if I travel much faster I don't get enough penetration). If I run 38 amps straight pull the weld comes out gray but with some color in it and when I brush it with a SS brush it comes out nice and silver. I'm using a 1/6" tungsten, a #8 cup with diffuser at 20 cfh argon. My question is about the color, what should I expect to get?
-Shannon
Guys, not to try to throw off the subject but reading this got me thinking. Being inexperienced in tig, is this also how welding say stainless exhaust or intercooler pipes should be done? Without filler rod/wire? Or does that only matter for the purpose of welding food grade materials?Rick_H wrote:Ah..the all mighty tri clover fitting. I weld those daily 316L stainless for Food Grade apps. Typically with a food grade job you would do a autogenous weld (no filler), full penetration with an argon back purge. Using filler is not ideal as you'll have too much reinforcement in the I'd of the piping and that could hold microbes or bacteria.
On .065" wall I'm around 38-43amps (travel speed will alter that), #8 cup, gas lens 1/16" tungs, and no pulse. You should end up fairly smooth inside and out, silver in color on the ID and the outside can be pickled clean.
Only on pharma, food and beverage is autogenous preferred. Reason being that you can oxidize your filler rod easily and there is a risk that you will contaminate root when oxides are moved from rod to weld pool. However it's not illegal to use filler and sometimes it's actually needed.
Also I would like to remind that really high purity lines are made with orbital. There is no way you can hand weld 300 perfect welds with smooth and shiny root! Also you can't give any document from hand welded weld. With orbital customer get receipt of every single weld, where he can see parameters and welding time sector by sector.
Also I would like to remind that really high purity lines are made with orbital. There is no way you can hand weld 300 perfect welds with smooth and shiny root! Also you can't give any document from hand welded weld. With orbital customer get receipt of every single weld, where he can see parameters and welding time sector by sector.
-Markus-
- weldin mike 27
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Weldmonger
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Joined:Fri Apr 01, 2011 10:59 pm
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Location:Australia; Victoria
Car guys (the less experienced ones) seem to like the smooth look of no filler. Doesn't mean it's right to do it all the time.
This will go little deeper and perhaps little off topic.
About those oxides....
On aluminium oxides is heavier than base metal and when aluminium is molten, oxides tend to sink down the weld pool due to gravity. (just like rock will sink to water). Oxide inside the aluminium weld is also well known failure and can cause rejection of the weld.
On steel and stainless steel things are different. Base metal in molten stage is heavier than oxides, so they won't sink that easily into the puddle. In other words there is no that big risk that oxides from filler rod will end up in to the root of the pipe.
HOWEVER we have keep in mind that in the weld pool there is always different kinds of driving forces, which will determine how the pool flows. These flows can help the oxides to travel into the root surface. Where it can become a spot for lowering corrosion resistance etc.
Which force is primary at the moment depends from:
- Alloying elements
- Arc pressure
- Shielding gas
[Source: http://www.arcmachines.com/news/case-st ... cts-sulfur]
About those oxides....
On aluminium oxides is heavier than base metal and when aluminium is molten, oxides tend to sink down the weld pool due to gravity. (just like rock will sink to water). Oxide inside the aluminium weld is also well known failure and can cause rejection of the weld.
On steel and stainless steel things are different. Base metal in molten stage is heavier than oxides, so they won't sink that easily into the puddle. In other words there is no that big risk that oxides from filler rod will end up in to the root of the pipe.
HOWEVER we have keep in mind that in the weld pool there is always different kinds of driving forces, which will determine how the pool flows. These flows can help the oxides to travel into the root surface. Where it can become a spot for lowering corrosion resistance etc.
Which force is primary at the moment depends from:
- Alloying elements
- Arc pressure
- Shielding gas
- WeldPool.png (41.35 KiB) Viewed 994 times
-Markus-