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Thread: Slag inclusions when weaving?

  1. #1
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    Slag inclusions when weaving?

    Hey all.

    I am still in school and I got my D1.1 certs soon (7018 rods, 3 and 4g, 3/8" plate with backing, 45 degree included angle, to be x-rayed).

    I've heard so many theories about weaves vs stringers and I still don't know what to believe. Does weaving cause slag entrapment? I have half of our instructors dead set against weaves in any form, and the other half teaching us to do them (not to mention Jody and the weldtube guy - among others on the internet I can somewhat trust - encouraging weaves for D1.1).

    Weaving feels good to me; it lays the bead flatter on the root/hot passes and it looks better. So (hopefully soliciting answers from those that have passed the D1.1), weaves or stringers? Does weaving trap slag? (also, our school has not had a working press for bend tests in awhile, so I am going into the certs kinda blind in that way)

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    Re: Slag inclusions when weaving?

    Its not really weaving. it's twisting and shoving the puddle left to right. The videos exaggerate the movement.
    Its only an 1/8 or so

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    Re: Slag inclusions when weaving?

    Thx Bonzoo....I've been moving too much then..... ~3/8" - 1/2"

    When I'm up and around from this knee replacement I'll get back to practicing.
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    Re: Slag inclusions when weaving?

    For the most part, I keep my weaving to the vertical up position. No, it doesn't burry slag. Just be sure to hold the toes to fill the undercut. Once you get a root pass and fill pass in, don't be afraid to turn up the heat.
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    Re: Slag inclusions when weaving?

    With 7018 minimum movement I find is best. We use mainly 3/32'' 7018 on pipe up too usually 6''. The smaller rod is easier to control especially when beginning. Once you can handle 3/32 work up from there.

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    Re: Slag inclusions when weaving?

    Are you talking about a basic pattern like you would doing 7018 uphill, or are you talking about lace caps?

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    Re: Slag inclusions when weaving?

    Age old discussion where there isn't always a meeting of the minds as to just exactly what 'weave' means. In my mind there can be a slight manipulation of the electrode that stays within the bounds of the normal bead width, then there can be a weave where you extend to the outer boundaries of single bead width in one or both sideways directions while still maintaining a forward progression. Vertical up is sort of at the boundaries of a weave to almost a zig-zag pattern. A zig-zag pattern where you are coming back across frozen slag is where there is a far greater chance of entrapping or incorporating slag in the bead. Not that one 'will' but the chances are increased.
    "The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt

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    Re: Slag inclusions when weaving?

    Quote Originally Posted by Bonzoo View Post
    Its not really weaving. it's twisting and shoving the puddle left to right. The videos exaggerate the movement.
    Its only an 1/8 or so


    jody's gap was 1/4" so i know that the weave was at least that wide
    Last edited by The5FootGiant; 01-05-2019 at 01:26 PM. Reason: meant to reply wit quote

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    Re: Slag inclusions when weaving?

    Quote Originally Posted by snoeproe View Post
    For the most part, I keep my weaving to the vertical up position. No, it doesn't burry slag. Just be sure to hold the toes to fill the undercut. Once you get a root pass and fill pass in, don't be afraid to turn up the heat.
    good advice thanks!

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    Re: Slag inclusions when weaving?

    Quote Originally Posted by walker View Post
    Are you talking about a basic pattern like you would doing 7018 uphill, or are you talking about lace caps?
    yes I'm doing uphill but what would be a "basic pattern"

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    Re: Slag inclusions when weaving?

    Quote Originally Posted by Sandy View Post
    Age old discussion where there isn't always a meeting of the minds as to just exactly what 'weave' means. In my mind there can be a slight manipulation of the electrode that stays within the bounds of the normal bead width, then there can be a weave where you extend to the outer boundaries of single bead width in one or both sideways directions while still maintaining a forward progression. Vertical up is sort of at the boundaries of a weave to almost a zig-zag pattern. A zig-zag pattern where you are coming back across frozen slag is where there is a far greater chance of entrapping or incorporating slag in the bead. Not that one 'will' but the chances are increased.
    I am doing a zig zag pattern going uphill, but i can stay within the weld pool, so i doubt i'm traveling over frozen slag. is a 1/4" to 3/8" side to side movement ok?

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    Re: Slag inclusions when weaving?

    With a 1/8 rod...........stick near 1/4

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    Re: Slag inclusions when weaving?

    This is what I call a weave. But Iím just a hobby welder!
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    Re: Slag inclusions when weaving?

    Quote Originally Posted by CEP View Post
    This is what I call a weave. But Iím just a hobby welder!
    Back in the late 70s I took a weld test for Code D1.1 verical and overhead, the QC was watchin me weld said it looked fine, I asked him do you want stringers or a weave? He said he didn't really care as long as that slag keeps peeling off like that and I was happy doin what I was doin weld it the way I see fit, just don't get it any wider than a 1/16 over at the face of the groove and no more than 1/16 reinforcement, so I weaved it and it looked just about like that picture except maybe a bit flatter. He liked it they cut and bent it and I passed, so I guess if your doin it right it don't really matter, unless of course they specify otherwise and today these QC guys and welding engineers have heart palpitations and get all bent out of shape over a weave. Ive even had to cut entire welds out with a torch that were a 32" too wide for maybe an inch or so with one of the beads on the cover on welds that were 1inch and more and 6 ft long and longer....silly if you ask me but hey that's what they want

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    Re: Slag inclusions when weaving?

    Engineers are hard to keep up with! Iíve worked places where they wanted weaves. Then other places they wanted stringers. I guess thatís why they hand you a WPS.
    Donít pay any attention to me
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    Re: Slag inclusions when weaving?

    One textbook recommendation seated in my grey matter was a recommended width of 5 to 8 times the rod diameter maximum. So for 1/8th rod max should be 5/8th to one inch. Yes when you weave you risk cold lap at the edges as well as slag inclusions. The reason some procedures desire stringers and no weave is to avoid cold lap at the edges. If you are REALLY good you can weave and create cold lap that can be missed in an X-ray :')
    I remember seeing some weaves on vertical beads that a supervisor was so proud of that his new welder had done. I smiled but shuddered inside. The weaves were close to an inch and a half wide. One sees this often on heavy equipment but almost never on pressure vessels. There must be a reason.
    When I have supervised students doing plate tests I encourage them to do stringers. Too many students who like wide caps end up with cold lap that opens up when the cap is bent. I don't outright ban weaves but point out the risk. It is their choice in the end.

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    Re: Slag inclusions when weaving?

    I need to start back practicing my vertical up stringers!
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    Re: Slag inclusions when weaving?

    Engineers and architects need to be dealt with aggressively. The majority are prix that dont actually know shiit.

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    Re: Slag inclusions when weaving?

    Quote Originally Posted by CEP View Post
    This is what I call a weave. But Iím just a hobby welder!
    This is exactly how I weave my vertical up cap and last fill pass all in one on any structural test.
    You never burry slag for the reason that the large puddle your carrying is soo hot. The very hot and large puddle can help burn out any crap that may be in your root or first fill pass also.
    On a 3/8" thick plate test. My root is stringer, then a stinger fill pass, then I weave the rest of the fill and cap all in one. Pretty hard to bury slag this way.
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    Re: Slag inclusions when weaving?

    Weaving generates too much heat....plain and simple. That's why they're frowned on.

    Excessive heat causes too much stress on the cooling weld. If it doesn't lead to center cracking, it wrecks havoc with distortion.



    I gotta prime pic of a center cracked weave on an earthmover, gotta find it.

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    Re: Slag inclusions when weaving?

    Iíve never been on a structural job where weaving was frowned upon. Thereís been a thousand posts on here on this topic.
    With low carbon steel like A36, (AWS D1.1 and CSA W47.1) thereís no such thing as too much heat.
    Medium carbon steel is a different story however.
    Jason
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    Re: Slag inclusions when weaving?

    to the OP, if your worried about having slag or what ever, do your test and cut the plates in two or 3 sections to allow you to see into the weld. if you polish up the ends, sometimes just cutting the test in half with the chop saw was enough polishing, you can put navel jelly on it and etch it out to see how your penetrating. if you do it right the weld material will turn slightly different colors than the base metal. you will see slag inclusions they will be very noticeable. heres one that I did. Its not a perfect weld, there was a tiny bit of slag in there and the root didn't go in right. this was when I was still learning. If could find the pictures of my T joints it would be even clearer. I did this a few times and learned that because of my rod/gun angle that I was trapping slag in the root of all my welds. I now take the stick electrodes and hold them more perpendicular to the metal, and my flux core I started dragging and the slag has gone away. If your testing out you might want to cut a weld or two. Name:  DSCF2079.jpg
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    Last edited by Scrapman Industries; 01-05-2019 at 10:58 PM.

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    Re: Slag inclusions when weaving?

    passing the bend test wan't the problem for me when I did them. Its the xray that screwed me. I had slag trapped in my welds because I was young and didn't realize what I was doing wrong. they still held, but slag is a big no, no on the xray.

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    Re: Slag inclusions when weaving?

    Quote Originally Posted by The5FootGiant View Post
    yes I'm doing uphill but what would be a "basic pattern"
    The uphill zig zag would be a more basic pattern, lace caps is the opposite extreme of weaving.

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    Re: Slag inclusions when weaving?

    Quote Originally Posted by lotechman View Post
    One textbook recommendation seated in my grey matter was a recommended width of 5 to 8 times the rod diameter maximum. So for 1/8th rod max should be 5/8th to one inch. Yes when you weave you risk cold lap at the edges as well as slag inclusions. The reason some procedures desire stringers and no weave is to avoid cold lap at the edges. If you are REALLY good you can weave and create cold lap that can be missed in an X-ray :')
    I remember seeing some weaves on vertical beads that a supervisor was so proud of that his new welder had done. I smiled but shuddered inside. The weaves were close to an inch and a half wide. One sees this often on heavy equipment but almost never on pressure vessels. There must be a reason.
    When I have supervised students doing plate tests I encourage them to do stringers. Too many students who like wide caps end up with cold lap that opens up when the cap is bent. I don't outright ban weaves but point out the risk. It is their choice in the end.
    .
    .
    usually weaving is limited to 3 rod diameters. at least thats what most welding rod manufacturers recommend. but then what do they know

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