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  • porosity in pipe xray

    I tested on 2" pipe using 6010 stringer and hot pass with 7018 cap. Test failed from porosity in weld. Approx. 12 to 14 inclusions in entire weld. I used an unopened box of rods I had bought approx. 8 month ago. This was a plastic container with tape to close.
    Going back to retest and will buy a new box of sealed metal can 70's. What else can be a possible cause for the porosity.. This is an severe code test where nothing can show on the xray. Thanks,

  • #2
    Porosity

    I find when using Basic Low hydrogen 7018 or 7016's you will always get porosity at the start of the bead unless you strike the arc then step back and burn out the area where you struck the arc. If you already do this maybe you should bake the rods . Its recomended to bake at 850 F for 1 hour and then maintain at 220 F until use. Other than that maybe arc length and interpass temps should be checked in case it gets too hot. These are things I found to help get clean X-rays. Hope it helps a bit and best of luck.

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    • #3
      Could be the rod, or you might have had a little to long of an arc / wrong rod angle.
      Did the 7018 come right out of an oven?
      Caution!
      These are "my" views based only on “my” experiences in “my” little bitty world.

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      • #4
        porosity

        Thanks Guys,
        Appreciate all your input. I have a little more info..

        Just got back from viewing the xrays. Porosity scattered throughout weld. I counted 10. Porosity was not grouped but singles here and there mostly in the center of the weld. I try to keep arc length to diameter of rod on the 7018, angle of rod is approx. 10 degrees and I might be running a little fast. Rods never saw the inside of an oven.

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        • #5
          Originally posted by taltexan View Post
          Rods never saw the inside of an oven.
          AWS D1.1:

          A5.1 is carbon steel electrodes for SMAW, A5.5 is low alloy electrodes for SMAW. Plain E7018 is an A5.1 electrode.

          Clause 5.3.2.1 states that the electrodes must be transferred directly from the hermetically sealed container into a storage oven maintained at 250°F min.

          Electrodes must be rebaked after exposure to the environment. Per clause 5.3.2.4, A5.1 electrodes must be rebaked for at least two hrs between 500° and 800°F. A5.5 electrodes must be rebaked at least one hr between 700° and 800°F.
          Caution!
          These are "my" views based only on “my” experiences in “my” little bitty world.

          Comment


          • #6
            c22reactor gave you good advice as to strike your arc and drag it back and you will burn the porosity out. Keep your arc as close as possible and you should be okay. This was the technique I always used and it worked for me as I could not begin to tell you how many carbon steel x-rays I welded in my 30 plus years welding pipe.

            Good luck,

            Wheelchair

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            • #7
              Originally posted by c22reactor View Post
              I find when using Basic Low hydrogen 7018 or 7016's you will always get porosity at the start of the bead unless you strike the arc then step back and burn out the area where you struck the arc. If you already do this maybe you should bake the rods . Its recomended to bake at 850 F for 1 hour and then maintain at 220 F until use. Other than that maybe arc length and interpass temps should be checked in case it gets too hot. These are things I found to help get clean X-rays. Hope it helps a bit and best of luck.
              Listen to this guy he know's what he's talking about. The place I work[formerly Combustion Engineering] made perhaps some of the finest stick rods ever known to exist. When all industry began cracking down on the use of asbestos and they changed there formula quality suffered along with the ongoing quest to drive out hydrogen from the mix has led to porosity issues on even the finest of stick rods made today. There is NO rod out there today that will be 100% porosity free unless the welder knows how to do what c22reactor suggested. When I make stick test that must x-ray I start out from the joint a inch or so and weld into the joint and come back and grind the excess weld of the tube. I also realize many don't have this luxury when performing qualifying test and if thats the case better listen to the advice giving and tighten up your game.
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              • #8
                Originally posted by Wheelchair View Post
                strike your arc and drag it back and you will burn the porosity out.
                I like to use that technique if nothing else it warms the rod up before depositing metal. Makes for good tie in.

                2-inch sch 80, 6-G, 6 o'clock.
                Attached Files
                Caution!
                These are "my" views based only on “my” experiences in “my” little bitty world.

                Comment


                • #9
                  Root to blame?

                  "Porosity was not grouped but singles here and there mostly in the center of the weld"


                  When you said the pores were mostly in the middle of the weld would tend to mean that the root is too blame . Would have to see the X-ray to be sure. Just somthing to keep in mind. hope it goes well and best of luck

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                  • #10
                    Originally posted by taltexan View Post
                    Thanks Guys,
                    Appreciate all your input. I have a little more info..

                    Just got back from viewing the xrays. Porosity scattered throughout weld. I counted 10. Porosity was not grouped but singles here and there mostly in the center of the weld. I try to keep arc length to diameter of rod on the 7018, angle of rod is approx. 10 degrees and I might be running a little fast. Rods never saw the inside of an oven.
                    It could be from the 6010. Porosity in the bead . It could be like was said before when you strike your arc do you drag it down to warm it up? Or do you just strike and go?

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                    • #11
                      Cluster porosity would likely be caused by LH rod with a cold start. As that is not the case here and the porosity seems to be distributed throughout the weld I would lean towards looking at the storage of the 6010 rod used for the stringer and hot pass as well as the technique employed. You have to move pretty fast on 2" pipe from top to bottom. I generally will place the rod in my stinger midway in the length of the rod where I have good control, not working from the end of a 14" electrode. Hopefully you are completing this weld with a start/stop at only the top and bottom of the weld and staggering their position between the root and hot passes. I assume you are running the 6010 downhill?
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                      • #12
                        porosity

                        Here are pictures of xrays ..
                        Attached Files

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                        • #13
                          Looked at the X-Rays, are you sure that it's porosity? Some of the defects look too big for porosity and that makes me think it's either in the root or slag inclusions. Was it a level 3 tech that read them? Can you visibly see what the root looks like?
                          Last edited by nocheepgas; 06-18-2010, 12:27 AM.
                          Miller Syncrowave 200
                          Homemade Water Cooler
                          130XP MIG
                          Spectrum 375
                          60 year old Logan Lathe
                          Select Machine and Tool Mill
                          More stuff than I can keep track of..

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                          • #14
                            I cant say as to the experience of the tech that read the film. The report stated porosity in weld. Pictures arent really good and clear but all of the "spots" in the film are all shaped in a circular fashion.
                            I could see the root in the test pipe and everything looked good.

                            Anyway going to get some additional pipe, dry rods and try to see if I can find the problem.....

                            Again thanks to all who responded.....

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                            • #15
                              Originally posted by taltexan View Post
                              I cant say as to the experience of the tech that read the film. The report stated porosity in weld. Pictures arent really good and clear but all of the "spots" in the film are all shaped in a circular fashion.
                              I could see the root in the test pipe and everything looked good.

                              Anyway going to get some additional pipe, dry rods and try to see if I can find the problem.....

                              Again thanks to all who responded.....
                              I would tend to lean towards a bead defect (either porosity or bubbles ) are you running uphill all they way or downhand bead and hot pass and uphand fill and cap? Just because the x-ray hand says it's porosity dosen't nessasarily mean he's always right. Jef

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