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Welding on Cat shear

Discussion in 'Demolition' started by typ4, Dec 3, 2010.

  1. typ4

    typ4 Well-Known Member

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    We have a cat shear made by Verachtert, and need some crack welding procedures asap. Mainly filler material specs, 7018 rod, or what ever is required.
    preheat,postheat so on, thanks.
    It is cracking around the upper jaw pivot and across the inside of jaw.
    Russ
     

    Attached Files:

  2. DirtHauler

    DirtHauler Senior Member

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    happen to have any zoomed out photos for referance? not sure what we are looking at there.
     
  3. typ4

    typ4 Well-Known Member

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    No zoomed out but it is the pivot area of the upper jaw. I will get oneup. It is in steilacoom come have a look.LOL
     
  4. John C.

    John C. Senior Member

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    Don't know the company that you work for but you have a very big and technical welding job there. Have you contacted the local dealer for the shear yet?
     
  5. fast_st

    fast_st Senior Member

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    Yeah, looks like a technical weld, likely would need preheat to 200f, a big v groove and a lot of nice 7018 LH electrodes. This is the kind of shear used for demolition right, it snips beams into small chunks.
     
  6. typ4

    typ4 Well-Known Member

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    The local dealers didnt even know CAt had a shear. We contacted the guy we got it from and he put me in touch with the Genesis repair facility and they gave some very good info. 10-4 on the 7018, preheat to 350 to 400 f , and it is a demolition shear,


    Here is our other shear, I dont think I am welding this one back on


    http://www.oilburners.net/forums/showthread.php?t=44030
     
  7. norite

    norite Senior Member

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    Don't know what grade of steel it is but it must be tough stuff. Maybe 8018 to 10018 rod for this job is required. Perhaps some kind of alloy? You need to find out what this thing is made of before you can come up with a repair procedure.
     
  8. typ4

    typ4 Well-Known Member

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    Yep, that is the plan. I may be taking a sample to a metallurgist I know if I cant find out.
     
  9. motrack

    motrack Charter Member

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    wow..... tore up another shear! That job is becoming expensive.

    You need to find some better operators.
     
  10. fast_st

    fast_st Senior Member

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    It'd be a bigger job than I could tackle for sure but my guess is you'd want to xray or gouge out that crack to the bottom then start welding from there, It looks as if it has been surface welded a few times and the cracks appeared at the stop points. The mfg might be able to tell you what alloy steel it is, to guide proper electrode selection.
     
  11. catmtl

    catmtl Member

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    I dont know who you spoke with at NC (cat dealer) But I would be happy to look at it and give you some options for repair. I have worked with CAT shears before.

    Jeff H
    PSSR
    NC Machinery Co.
    206 261-0002 cell
     
  12. adam21584

    adam21584 Well-Known Member

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    Grinding out the crack will tell you a little about how hard the metal is. mild steel will grind with sparks going a long ways and yellow. harder plate sparks are more red, and don't travel as far. 7018 or 10018 should be fine, for about anything repair wise. Air arc would gouge out the crack allot faster and cleaner.
     
  13. loggah

    loggah Well-Known Member

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    I have a old Labounty msd 220 on my cat 235, the labounty shear is fabricated out of T1 steel ,any buildup welding or repair the factory says to preheat to 300-400 degrees and use 7018 rod ,i know its not a cat shear but it could be similar. Don
     
  14. typ4

    typ4 Well-Known Member

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    Well my good friend Dan is up here and he is a very experienced welder and he torch scarfed it out, ground it and did the preheat, welded it up with dualshield wire of the recommended alloy and it has ran for a week , so far so good. All the welding done by the PO was very poor.
    Thanks for all the great info. I will keep posted, we are winding down on the job so hope it makes it to the end.
     
  15. DirtHauler

    DirtHauler Senior Member

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    Happen to get any pics of the repairs in progress or of the finished product. I have not worked with shears at all and am just curious. My first impression from the photos of the cracks ment a total loss for the shear. That is why i love this site, learn new things everyday. Now if only i could convince other people i work with that i am not just a stupid know it all truck driver... Well maybe they have a point on sometimes :D
     
  16. typ4

    typ4 Well-Known Member

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    No he did it on the weekend while I was home, we kinda rotate so one of us is here all the time. We figure th ere is nothing to lose if its cracked and we weld it, it may fail but if it buys some time then that is money not spent.
     
  17. Deeretime

    Deeretime Senior Member

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    IMO 6010 Root then 7024 only good if you can get the shear flat tho, no good for upper hand. Take some pictures of it when its done!
     
  18. hvy 1ton

    hvy 1ton Senior Member

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    Gotta love dual shield, you can really lay down some metal with it. It's right up there with 6011 for being able to weld 2x4 back together too. :D
     
  19. Lee-online

    Lee-online Senior Member

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    I know its a little too late but I just stumbled onto a procedure to repair the large B series demolition and scrap shears.


    (1) Weld cracking may occur at the housing/hub transition.

    shear2.jpg



    Fabricate the Reinforcement Plate

    Fabricate two reinforcement plates from an Alloy Heat Treated Structural Steel that meets ASTM A514 or equivalent material. Refer to Illustrations 2, 3, and 4 for plate dimensions.

    *I did not add the Illustrations.

    Weld Repair and Rework Procedure
    Follow the instructions for pre-heat, inter-pass, and cooldown requirements.


    If necessary, gouge out any existing weld cracks down to the dowel hole.

    Preare the area for repair welding.
    The housing and hub material must be preheated to 150° to 175°C (302° to 315°F). Preheat an area extending at least 203 mm (8 inch) beyond the area to be repair welded. Weld inter-pass temperatures should be 125° to 175°C (257° to 315°F). Do not weld in ambient temperatures below 15° C (59° F)

    If necessary, make the repair weld root pass at the top of the dowel hole and ensure uniform penetration and bean consistency.

    Locate the reinforcement plate (2). the plate should be located on the hub with the edge of the plate 20 mm (0.79 inch) from the edge of the housing shown in Illustration 3. The weld should not contact the hub nut guard (small piece on the outside of the hub). The weld cannot penetrate the outside weld or the hub nut guard. Refer to 4.


    Place a 12 mm (0.47 inch) fillet weld all around the reinforcement plate. The recommended penetration is 1.5 mm (0.059 inch) minimum.

    Cover the repair area with welding blanket and allow weld to cool to ambient temperature.
    Note: Area must not cool more than 50° C (120° F) per hour.


    Repeat Steps 1 through 8 on opposite side of shear.
     
  20. typ4

    typ4 Well-Known Member

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    If you have those pics for the plate that would be good.

    Thanks for that info. I think that may have been done, The crack we had was on the upper jaw to hub-pivot area.

    It has not cracked since and has more time on it than it did before the crack.:D