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    Default A crane we made

    "we stand behind our cranes, but never under them"

    I mentioned in another thread we were starting to make some cranes. I thought I share a pic. Here's the second - an 80' box girder just painted, waiting for installation of commercials. I invested lot to be able to make these, sub arc machine, bench, huge spreader bars etc. I hope to ( I better!) make a lot more....but its neat seeing it come together sitting there in monolithic glory. Stuff on the right is a large truss conveyor

    cheers


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    What are the specs?

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    8 or 10 tons irrc, I should know, got a great memory but its short. We're a design build shop, but not on the cranes.... just building to print.

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    Why subarc? Just what the customer wants or? Just curious, don't really know diddly about subarc.

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    Brings back memories. I did 11 months making cranes and end trucks. The big thing is alignment for that smooth running install. Of course it all goes south if the building is not on a firm foundation. I was in one shop where the crane brakes would not hold and the bridge would roll down to the low end of the building. They had a crew come in on a Saturday and put bolsters under the rail supports. The bolsters were over a foot high. The building was sitting on peat bog. At lunch time guys would throw a lighted match at one of the cracks in the floor and you would see a blue flame flicker along. ( swamp gas )
    It was weird running a load lengthwise in the building. Your hand would rest easily on the end of the load and by the time you got to the far end you were reaching to shoulder height.

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    Quote Originally Posted by kustomizingkid View Post
    Why subarc? Just what the customer wants or? Just curious, don't really know diddly about subarc.
    Sub arc is an old process and well proven. You get a relatively high penetration weld and the flux gives a nice controlled cooling. Being automatic it is easily repeatable for each bead. The operator qualifies and an "operator" on his welding qualification.
    Submerged arc does not like oil from pneumatic grinders. For some reason you can have trouble with flux core tack welds. Sub arc likes small tacks made with hard wire as long as the tacks are small. I had massive problems on one production run because the assemblers would leave huge gobs of weld metal for a tack rather than a little inch long fillet that could be melted through. I showed examples of what happened ( porosity) when welding over their gobs and demonstrated that my assemblies welded up with no porosity when I put in long thin tacks. As soon as my back was turned..... Grrrr.

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    Quote Originally Posted by kustomizingkid View Post
    Why subarc? Just what the customer wants or? Just curious, don't really know diddly about subarc.
    A key reason is evenness of the weld. You weld one side and it pulls and has definite bow, you flip and weld the other and comes back straight. That depends on an even weld. That plus the quality, appearance and hours should all be better. Basically this comes form one of my guys who has 30 years building these things as a shop foreman so I went with how he wanted to do it to the letter - and the customer is crane manufacture who has just as much experience and carefully scrutinized our proposed process. End of the day its my guy who said we had to do it this way, but we also wouldn't have had a customer if we didn't

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    Quote Originally Posted by Mcgyver View Post
    A key reason is evenness of the weld. You weld one side and it pulls and has definite bow, you flip and weld the other and comes back straight. That depends on an even weld. That plus the quality, appearance and hours should all be better. Basically this comes form one of my guys who has 30 years building these things as a shop foreman so I went with how he wanted to do it to the letter - and the customer is crane manufacture who has just as much experience and carefully scrutinized our proposed process. End of the day its my guy who said we had to do it this way, but we also wouldn't have had a customer if we didn't
    Fair enough... its basically like an automated wire feed stick welding hybrid right? But instead of flux coated to the rod its powder that is fed as it welds?

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    Quote Originally Posted by kustomizingkid View Post
    Fair enough... its basically like an automated wire feed stick welding hybrid right? But instead of flux coated to the rod its powder that is fed as it welds?

    Submerged arc welding process - Job Knowledge 5

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    This video shows the process reasonably well...

    Sub Arc Welding - SAW - YouTube

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    If you want to make money doing it, you want a twin head sub arc and you hit both sides in one pass. Compared to mig deposition rates are vast, 5-6mm filler metal is common, were i use to be had a twin head gantery setup 1000A on each head and a onsite diesel generator to power it. They use to grind the tack welds down as it went along. its a really nice and clean process compared to mig and once travel speed and current + wire speed are set, its just a case of keeping the laser spot were you want the weld fillet. Oh yeah and 2 seriously heavy earth leads per welder! The nice part is its so much more operator friendly, you can literally stand besides it with just safety glasses, theres just a crackling noise and a hot glowing puddle of flux, no arc visible at all. When running right the slag just curls up and falls off.

    The tack welds on beams like that are a major source of crack starters, in some ways, they need to be more tightly controlled process wise than the actual main welds.

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    I don't see any holes in the side plates.

    I am told they are to check for overloads.
    An inspector climbs up there every year or so, and checks for out of round.

    Maybe it's only certain sizes or manuf's ?

    Subarc get's pretty fancy, what with 3-4 wires, a-c, d-c
    on seperate wires, etc.
    Untitled Document

    Good to hear of some of the problems (hobbyman)
    and how to avoid them (the finicky bits)
    as well.

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    Sub arc is heavily dependent on procedures and procedure qualifications. In one shop I was in we were doing welded wide flange beams. They were for highway over passes and were taller than a man. The center webs were spliced to make a 30 metre section. Each piece was flame cut to a curve on an NC burning table. The spice on the half inch plate was a square butt joint. I had to set up a couple of the joints. The operator ran something like 300 amps on one side then they turned it over and he ran around 600 on the opposite side. No bevel preparation and a perfect weld every time.
    When the flanges were welded on the beam of course they had to have a camber. The day lead hand asked me to check the beam they had just welded so around ten in the evening I set up the wire that was on a boat trailer winch. I tensioned up the wire then measured the camber and it was right to the millimetre! Tolerance was something like plus or minus 7 mm. I left a note for that lead hand on day shift. The next day I mentioned how it was dead on and he pulled out a little pocket book with his notes. He made the comment that even different operators would give him slightly different cambers. Not by much but he could see it in his notes each time.
    I visited on operation on a tour where they were doing similar beams but these ones were cambered and also curved. On those they used an automatic flux core machine and did everything with the beam in one position. Two fillets were done overhead and two down on the horizontal.

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    Have you started making cranes in Canada because of Trump's steel tarrif?

    L7

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    Quote Originally Posted by lucky7 View Post
    Have you started making cranes in Canada because of Trump's steel tarrif?

    L7
    We export lots to the US but not that crane, its a domestic installation. I think with a crane there are reasons to have it made locally, its 80' so transportation is expensive. The big crane companies all seem to do so, that is make them locally.

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    Quote Originally Posted by digger doug View Post
    I don't see any holes in the side plates.

    I am told they are to check for overloads.
    An inspector climbs up there every year or so, and checks for out of round.

    .
    That's a new one on me. We have about 40 overhead cranes that get inspected annually by a 3rd party and that has never come up. And I don't remember seeing any holes on any of the plates.

    If the crane is overloaded, the hoist or wire rope should fail before the structure deforms.

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    Quote Originally Posted by bloomautomatic View Post
    That's a new one on me. We have about 40 overhead cranes that get inspected annually by a 3rd party and that has never come up. And I don't remember seeing any holes on any of the plates.

    If the crane is overloaded, the hoist or wire rope should fail before the structure deforms.
    I'll have to poke around a bit more, double check next time I see one of the crane
    inspectors.

    Maybe it's only on the larger cranes, 100 ton and up.

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    I was out in the boonies to a tank fab shop (getting some parts plasma cut)
    And they do large silos (field welded)

    The showed me a tank riding sub arc, it holds the flux up to the weld
    with a rubber belt.
    Submerged arc welding horizontal 2G - YouTube

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    I've been in a lot of shops that did long steel weldments, everything from bridge beams, to mobile crane booms, to overhead cranes. Almost all use submerged arc.

    The overhead crane business is booming right now, most manufacturers are running several months behind.

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    I worked briefly for a company that made overhead cranes in the UK ( Matterson Ltd ). They had a huge gantry type sub arc welding machine in one enormous bay. It had multiple welding heads on a travelling cross rail arrangement like a Plano-mill. There were three overhead cranes in that bay that could be ganged together electrically to be used by one operator for turning the box beams over for subsequent welds.

    All the beams were cambered so the load was trying to pull the beams downwards.

    Regards Tyrone.


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