Tig SS pipe Problem!
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  1. #1
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    Tig SS pipe Problem!

    Hello,

    On this new project I have been working on getting some .109wall 304SS tube welded up for a manifold. I am getting full penetration but seem to be having a problem with the weld appearance and need some input.

    I am using a syncrowave 200 for this project and have tried both 308 and 309 filler. I have also adjusted the gas flow between 10-20 cfm and have a back purge setup at around 5cfm after flooding. Also have tried both 1/16" and 3/32" tungstens and the same on filler.

    I have links below for the tube and two pictures of what the welds look like.
    Any guidance would be greatly appreciated.

    Robert

    Tube info

    Picture 1

    picture 2

  2. #2
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    Re: Tig SS pipe Problem!

    might be too hot..

  3. #3
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    Re: Tig SS pipe Problem!

    Your overheating the material, what amps are you running? Regardless, you need to find a way to reduce your heat input. Either less amps or faster travel speed.
    Have we all gone mad?

  4. #4
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    Re: Tig SS pipe Problem!

    Opps forgot that part. 110 amp cap.

    I tried several more things since my post and can not get it to look right. I tried to v cut deeper and do a root pass at very low amps with no filler, but could not get penetration to the backside without using filler. Using filler with just enough amps to melt the 1/16 rod into the puddle it would get that look the pictures show. I also tried different speeds, but still no luck.

    I'm pretty sure these are a cast tube. Having never tig welded cast, could that be causing the look?

    Robert

  5. #5
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    Re: Tig SS pipe Problem!

    Could the problem be related to the "Made in China" marking on the pipe?


    Rex

  6. #6
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    Re: Tig SS pipe Problem!

    Are you running a gas lens in your torch? If not, I would get one of those. 110 Amps should be alright for doing that, so its more likely your travel speed. Another thing that might help is to try using the pulser to reduce your heat input.
    Have we all gone mad?

  7. #7
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    Re: Tig SS pipe Problem!

    Way too hot. 65 to 75 amps. The dull appearance is from too much heat.
    UA Local 598

  8. #8
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    Re: Tig SS pipe Problem!

    Quote Originally Posted by WHughes View Post
    Way too hot. 65 to 75 amps. The dull appearance is from too much heat.
    If he wants to get full pen on 12ga tube, your going to want more than 65-75 amps. I run that on 16ga tube and sometimes still want more.
    Have we all gone mad?

  9. #9
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    Re: Tig SS pipe Problem!

    I would think that you are moving to fast. And not cooling, or coming off the heat between beads.
    If you have backup gas, take your time relax. If you start the weld and create the first bead with no filler wire, you are at the right temperature. The trick is to move in very small increments. So small that you would think you won't get a stack of dimes.

    You heat, add wire, let the wire level out, come off the heat, wait till the puddle cools, and move just a tiny bit forward, and do that again and again.

    When you add filler wire, wait for a long time while applying heat until you see the puddle blend totally with the base metal. Then shut off the heat, wait till the puddle cools and move on.

    Much of our stainless is from China. Only the hydraulic grade seems to come from American companies.

    This is with no backup gas. I use a gas lens and a 1/16" tungsten.







    I let the tungsten stick out more then in the picture. That was just placed in there for the picture.

    If I had to do a bunch of these, I would use backup gas, probably use more heat for speed and slightly cleaner look.

    But I believe I did these to show that you can weld schedule 40 Stainless steel pipe with a small inverter welder. I kept my amps well under 90 amps. Probably around 70 amps.



    Sincerely,


    William McCormick

  10. #10
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    Re: Tig SS pipe Problem!

    Incorrect torch angle & too slow? (The demo is 303.)
    Attached Images Attached Images   
    "SOUTHPAW"
    A wise person learns from another persons mistakes;
    A smart person learns from their own mistakes;
    But, a stupid person.............never learns.

  11. #11
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    Re: Tig SS pipe Problem!

    yes lower the heat go slower and let argon do its work

  12. #12
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    Re: Tig SS pipe Problem!

    Quote Originally Posted by sn0border88 View Post
    If he wants to get full pen on 12ga tube, your going to want more than 65-75 amps. I run that on 16ga tube and sometimes still want more.
    Wrong wrong wrong. That is way to hot for .109 tube. I'm a boilermaker and weld ss xray joints all the time and even on heavy wall tubing I very rarely go over 80 amps. I'd say no more than 70 amps and you better be moving at that. Btw the pics are some .440 wall tubing I welded at work and never had my heat any hotter than 78 amps.
    Attached Images Attached Images    
    Last edited by Showdog75; 05-08-2010 at 08:30 PM.

  13. #13
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    Re: Tig SS pipe Problem!

    Quote Originally Posted by sn0border88 View Post
    If he wants to get full pen on 12ga tube, your going to want more than 65-75 amps. I run that on 16ga tube and sometimes still want more.
    You have been mislead. Overheating stainless causes it to behave very sluggish, especially without a purge. It also gets very dull looking, like in his original pics and when that happens, it looses its corrosion resistance properties.
    UA Local 598

  14. #14
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    Re: Tig SS pipe Problem!

    Probably several things not quite right, two that jump out to me are arc length and from the area i circled in red (used the 2nd pic) torch angle

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    If you lose the torch angle as you progress around the pipe the arc length increases. Longer arc length = more heat input but poorly focused i.e. it's wasted heat. Too long an arc length can also mess with quality of the gas shielding

    If the filler wire isn't kept within the gas shield then the end will oxidise and you dip oxidised wire into the pool. If the end of the wire is discoloured then that'll be adding to the problems

    The joint set up in the pics is going to need more amps than a set up that has a root gap and/or knife edged bevels which in turn will make it harder to avoid dull welds. All of these factors have an effect on amperage

  15. #15
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    Re: Tig SS pipe Problem!

    Well we can just agree to disagree then, I believe those settings work great for you guys. I ran a SS pipe the other day with an EB ring (3"XX heavy I think), 100-110 on the root pass and at least that on my fill passes. No color on the backside (w/ purge of course), and no grey color on any spot during the fill passes.
    Have we all gone mad?

  16. #16
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    Re: Tig SS pipe Problem!

    Thank you very much for all the input! Looks like I will go buy a gas lens on Monday and work on some scrap material I have. I will try a deeper bevel cut and do a root pass and layer on top of that. I will probably cut that weld back out and replace the tubes so as not to have a problem.

    Thank you again.
    I will post up my results Monday night.

    Robert

  17. #17
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    Re: Tig SS pipe Problem!

    sn0border88, Showdog75
    just curious if the amperage(s) you're each referring to was checked: while welding (?) with a clamp-on ammeter (????) or were these settings on two different brands and models of power supplies?

    We have measured an older Lincoln 300/300 TIG set at 175 A welding consistently at 150 A and the newer Miller Dynasty 300 DX set for 175 welding at 175.00A.

    I'm not sure the settings of all power supplies are the weld power we've got at the torch, - all that matters is the bead and finished weld, (and the X-ray)?

    Apples and Oranges?

    rs_customs, your original welds look way too hot to me.

    Cheers,

  18. #18
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    Re: Tig SS pipe Problem!

    I've also crept up to about 100 A on around 12ga and thicker SS. the thing is we were moving, very high travel rate. heat input is an exponential function of travel speed and only a linear function of Amperage. If you travel faster at 110 A you'll put in a lot less energy than traveling slow at 60A.

    That being said most people are not comfortable OR not practiced enough to hit the very high travel rates, or the joint has bad enough mismatch that you're likely to blow through. I used to run high amperage on my fill passes to lay them in fast and have it wet out.

    not for the beginner though, stainless doesn't need a lot of heat.
    Welding Engineer
    Certified Scrap Producer

  19. #19
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    Re: Tig SS pipe Problem!

    I agree that if you get it right, you can turn up the heat, and move. Leaving a golden weld behind you. Usually though for someone not used to stainless steel, it is better for them to go a bit slower. From my own experience.
    Sometimes you get a bit more distortion, but I have found those welds to actually hold better then some of the colder welds done by better welders, or airline.

    But if you practice on butt joints for a few days, practice sinking the puddle exactly, you will be able to just rip through those welds.



    Sincerely,


    William McCormick

  20. #20
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    Re: Tig SS pipe Problem!

    Quote Originally Posted by William McCormick Jr View Post
    (snip)

    But if you practice on butt joints for a few days, practice sinking the puddle exactly, you will be able to just rip through those welds.

    Sincerely,
    William McCormick
    William, I've been at it a day or two and don't tig SS much (and have never been happy with it without pulse, and then "not that happy"). When I saw your first post bells went off in my head!!!

    I've done a lot of tool steel welding and that is almost the exact procedure, with the exception that no puddle is really started before the rod is laid down with TS. The heat is started then directed over the rod to "sweat it down" and move on (never puddle around or the chemistry gets bad and the tool is POOF).

    Damnation! Now I can't wait to get some fiddle time...

    For those real welding folks reading this I just remembered what happens when chrome is overheated...

    Matt

  21. #21
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    Re: Tig SS pipe Problem!

    Im using the same crappy china material for my exhaust parts im making as well. But just as everyone has said.

    -Use a gas lens. I use a gas lens on everything. And get the biggest cup you feel comfortable with as well.

    Here is a Tial wastegate flange Im welding on some schedule 10 pipe. FWIW I believe I welded this around 75 amps IIRC.

    -Back purging stainless is VERY important, you will notice a night and day difference if the way your welds look just by back purging.

    -Keep your torch angle more perpendicular to the base metal (this is where its tricky because you moving around a tight circle) to keep the sheilding gas flowing over the weld you just laid. And this also is where the gas lens and larger cup help as well.
    Last edited by SR20steve; 05-10-2010 at 11:43 PM.

  22. #22
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    RE: New Pictures!

    Here are tonights pictures! I put pulse to use on this and the new gas lens with a #7 nozzle. Root settings no filler=90amps pps .5 (PT 40) (BK A 15). Filler Pass settings = 110amps same pulse settings as root.

    I didn't have enough back purge on this particular weld so the inside doesn't look as nice as it should.

    I have a few more pictures if needed and there are two video links at the bottom of the post that show the tube being rotated to show the finished welds.

    Please let me know what you guys think. I am a lot happier with the results and greatly appreciate the help!

    Robert








    Root Video

    Filler Video

  23. #23
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    Re: Tig SS pipe Problem!

    The last ones looked much better.

    You are moving in too large an increment, or moving too much forward at each bead. Move half as much for each new bead.

    Don't be afraid to burn in stainless. Not burn the surface, but rather melt the bead more level. You will see that the weld edges blend with the metal tube. The heat will stay with you more if you totally properly heat the bead. The heat will actually leave the part behind the weld, and follow you. Rather then stay there and burn the surface.

    If you heat the part, start a bead with no filler, add filler, level out the filler. Chill the bead, move ahead just a bit, and do it all over again. You will get that amazing looking bead. And you will actually be moving faster, because of the heat and the way it follows and preheats for you.

    You will see that when your flow is more unpracticed and natural. That the heat stays with you, and you will find that you are welding probably faster then you are used to welding. Once you get that rhythm going. The heat stays just where you are welding.

    Sincerely,


    William McCormick
    Last edited by William McCormick Jr; 05-11-2010 at 12:27 AM.

  24. #24
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    Re: Tig SS pipe Problem!

    Quote Originally Posted by William McCormick Jr View Post
    The last ones looked much better.

    You are moving in two large an increment, or moving to much forward at each bead. Move half as much for each new bead.

    Don't be afraid to burn in stainless. Not burn the surface, but rather melt the bead more level. You will see that the weld edges blend with the metal tube. The heat will stay with you more if you totally properly heat the bead. The heat will actually leave the part behind the weld, and follow you. Rather then stay there and burn the surface.

    If you heat the part, start a bead with no filler, add filler, level out the filler. Chill the bead, move ahead just a bit, and do it all over again. You will get that amazing looking bead. And you will actually be moving faster, because of the heat and the way it follows and preheats for you.

    You will see that when your flow is more unpracticed and natural. That the heat stays with you, and you will find that you are welding probably faster then you are used to welding. Once you get that rhythm going. The heat stays just where you are welding.

    Sincerely,


    William McCormick
    Would you say half the distance for both the root and the filler or just the filler pass? I will play with the PPS setting and get a little longer pulse/heat into the part. Or do you have any pulse recommendations? I tried one of the previous welds on the tube with just foot control, no pulse and was basically just doing tack welds, but didn't have a good uniform look. I may have needed to do a tighter layer like your saying there also.

    Thanks again.

    Robert

  25. #25
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    Re: Tig SS pipe Problem!

    Looks allot better, and you purged it this time? I know this is just practice but when you do a real joint you should take a drum flapper to the outside and inside to get good clean metal to weld to. And stuff that thin I don't think you should have to bevel it, but the slight bevel with a land wont hurt (and help be a guide as well).

    If it was me I wouldn't use any pulse, just use the pedal and just get in a nice smooth torch movement and get in a nice rthym of adding filler metal. As you go allong you will notice the puddle getting flatter but then you can just back off the pedal till you see the bead grow taller and narrower. The nice ripples will be from you adding filler. I seem to have the best appearance (this is subjective though) just tapping the filler in slightly but frequently.

    And remember to lower you amperage if you take it off of pulse.
    Last edited by SR20steve; 05-11-2010 at 12:27 AM.

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