Welding chain

At times, like when you want to make a loop of chain, and when you just need to make something up, what is the best way to weld shut a piece of chain?
As in the case of when you cut a link, and want to put it back together again.
Is the best solution a cold shut, then run a hot bead around the stub?
I've run into this lately, and seen some chain connections that "looked" strong, but as an old rigger, I know that looks don't mean squat. I'd like to destructively test these and see where they did finally part.
Just like to do rigging stuff 3x the SWL, and know that when I start REALLLY pulling on something, what's likely to happen. It's always nice to analyze failures after the fact when no one was hurt, or nothing damaged.
TIA
Steve
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What's that Lassie? You say that SteveB fell down the old sci.engr.joining.welding mine and will die if we don't mount a rescue by Mon, 9 Nov 2009 15:47:43 -0700:

In one of my old welding text books, they show round stock being joined with a double bevel joint. I wouldn't trust such a connection though.
--

Dan H.
northshore MA.
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I agree. If you can't weld an open root, then the best thing is not to.
Steve
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We aren't talking roller chain here.
I would imagine the new riggers would only use equipment with tags. If you have employees probably you should do that. I think you are asking about a loop like in a manual chain fall or hoisting apparatus.
I have had good luck with my dc tig argon and 70s6 rod. bevel so you are sure the thing is welded solid with no missing voids. In the 5/16 size I haven't broke any of my welds with a 5000 pound tractor and all the lift it will provide for additional traction. Usually I use chains I bought new or just put new slipper or grabber hooks on with the pin and split pin or cotter pin onto a healthy link. Of course there are some weaker grades of chain than others. And some of the tagged stuff the links are more complex than just a rod bent in an oval. Perhaps someone else will be able to tell you what grade of chain is too high carbon or alloy for my technique. I don't do yanking techniques. You can be pretty sure of what you are doing with tig. A real pro probably could with sticks. I also have some connector links which consist of two halves which overlap with kind of like rivet like things built in. They seem somewhat thicker than the nominal chain size they are to splice. I know there are other kinds of splicing links.
What do you think they use at the chain factory? electron beam welding?
Fran
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"fran...123" wrote:

How It's Made had a segment on chain production. They showed the annealed wire being bent, what appeared to be resistance welded, induction heat treated, quenched and proof tested all in a continuous operation. Pretty nifty, especially the proof testing where it would advance a short section of chain between two pull hooks and then apply a calibrated load and measure the stretch, if good it would remove the load, index the next section into place, test, etc. Every single link in the chain was tested.
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The videos I saw they used electric current to heat the links red hot, then the two stubs were pushed together. The chains I am referring to would not be used in critical lifting, just in situations where maximum load would be no more than fifty percent of SWL. I know better than to pull hard on something you're not 300% sure of.
Steve
Steve
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Assuming this is regular steel, not Grade 120 or some such...
To me, it is a no brainer -- bevel and TIG, and use at reduced load rating afterwards. If you want to not reduce the rating, use special chain links for connecting chains. They are not that expensive. Either figure eight connectors, or jusk links with a side with a threaded collar that can be opened and closed.
i
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says...

I would recommend a full-penetration weld. Leave enough gap between the ends so that the arc can move from side to side, avoiding a "cold weld". Use a ceramic backing or perhaps a piece of heavy clean copper. Flat can be made to work, but with copper you can shape it to a closer match to the links, giving less grinding later.
Chain is typically flash welded, but it is possible to use manual methods. What you really need to do though, after welding, is to re- temper the welded link. After welding, the Heat-Affected Zone (HAZ) will be very brittle compared to the rest of the chain. Proper temper differs with material type, so if you know that, the temperatures, holding times, and cooldown rates can be found online in most cases.
--
Tin Lizzie
"Elephant: A mouse built to government specifications."-Lazarus Long
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SteveB wrote:

Steve, I have a friend who does theatrical rigging, including flying performers (ala Peter Pan). He has set up a destructive testing lab, with a 5 ton load cell, and accessories. If you wanted to make a few samples of chain, about a foot long, with the splice in the middle, I could send you his info. He likes using his toy to break things.
Stuart
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best http://www.slingchoker.com/sling2/crosby/v/v145.htm#A-336 not for lifting http://www.slingchoker.com/sling2/crosby/v/v146.htm#S-249 not for lifting (IMHO these just don't look solid) http://www.slingchoker.com/sling2/crosby/v/v144b.htm#PEAR SHAPE see notes re pear links @ http://www.thecrosbygroup.com/html/default.htm look in the chain & accessories section

This is hardware store (poor) quality stuff which may? be ok for something like repairing (snow) tire chains, or pet dog chains, but there are better solutions.

On the sites I work on, NO lifting is permitted with ANY chain, even tagged and certified stuff.
Similarly NO lifting is permitted using ANY field fabricated rigging, and NO chain hooks are permitted to be field welded onto dirt-buckets. ALL lifting equipment must be certified (by engineer or manufacturer) and have a current engineer's NDT inspection.
Most of the traditional uses of chain have been abandoned in favour of MUCH better and safer materials.
Repairs on NON load bearing chains such as pet dog chains or man powered side of a chain hoist can easily be welded with 7018. Most manufactured chain will stretch a bit before it breaks YMMV but all bets are off for welded product.
Load or decking chains (should be proof type) used for securing transport loads should NEVER be welded.
IMHO welding a chain is a CRIMINALLY NEGLIGENT act as you have no control over the task that someone else may attempt with what is now an unmarked and hazardous product that meets no standards or quality control.
IMHO, ANY welded chain has a lawyer attached.
Good luck, YMMV
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I agree with all you said. But you are referring to heavy construction use situations. I have worked in those, and know that the lifting rules are very different there than around the house. Around the house, one is hardly likely to put a really hard pull on anything, so just "good" equipment will do the job. Or get you killed.
Then there's "by the book". Offshore, lifting anything by rope was prohibited by OSHA. Yet, when we wanted to unload loose timbers or 2 x 12's from a boat with a crane, we'd get a 1" manila line and throw a timber hitch on it and hoist away. Of course, keeping personnel out from under the load and swinging over the water. So long as you don't lift more than two, they don't slip, and rope and timber hitches work great.
I've seen all kinds of creative rigging that worked for that situation, and then overkill rigups that failed.
And yes, I thoroughly agree with and have seen your point in action about what another person would do with something you made up, or were familiar with using and they weren't.
Yet, with all the regs and rules, we still have failures and accidents.
Really, chains are used for very few critical applications nowadays, and socketed steel rope is preferred. If I was rigging up something professionally, chain would be my last choice because you have so many failure points. If I'm using it around the house, and it's not on a machine that I know can overload it, I do not hesitate to use it. Most of the stuff around the house isn't like picking up a Hydril or BOP.
Steve
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I agree that 'if rules could make the world safe, then we would not have had any accidents for at least 20 years.'
We have both been 'in the patch' long enough to remember the bad old days when skin and lives were expendable and safety was always compromised for economy or speed. Industry has discovered that accidents are much more expensive than previously thought and current thinking does not tolerate unsafe actions and practices. You have raised the example of hoisting planks with ropes, and while the scaffolders still do a lot of this they are the only trade that still does much of it, the rest of us use (and even the scaffolders prefer as less work) certified material baskets which will safely move in one lift what it used to take a whole crew several hours to do by hand with a rope and pulley.
Chains were very commonly used in the past but that was before we recognized just how often their failure was the cause of injuries and property damage. We transitioned to cable slings which were a LOT safer but today use few of these as nylon and Kevlar is lighter, stronger and just plain nicer to use. They have just about eliminated hand injuries from cable jaggers and are easy to visually inspect. They also make very good chokers (particularly the endless loop or grommet type) and you would prefer them for hoisting planks as they grip every bit as well (or usually much better)as a rope but are much stronger and are certified.
It has been a lot of years since I have purchased a new chain and even the truckers only use (very large sizes) them for very specialized purposes (securing tracked machinery, and they have stopped using lever load binders in favour of the screw type. Young workers no longer even know what a 'snipe' is). Most of the chain still in use is very old stuff that has been discarded (usually broken and shortened) by the original users who are now using better products. Flat webbing with deck winches and ratchet straps are lighter, easier to use and safer for most applications.
It is a sad fact that we are usually safer working on big jobs for big employers, and that we are most at risk when we are around small and independent operators who either have never learned or don't want to work safely. We routinely do thing with ladders around the house that would get us fired on the job. We were taught to never waste tools that are still usable and to 'make do with what we already have' but this too often results in our using products and procedures that are neither efficient or safe. I do not mean to preach or lecture the group here, but I have found and learned a lot of good information here and wish to make some small contribution to those who may have come here as hobbyists and who lack the kind of formal safety training you (SteveB) and I have been exposed to.
Good luck and 'Worksafe'.
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We are talking about retired SteveB lifting an engine out of his truck, unloading a welder from his pickup, pulling an ATV etc. These are small loads, usually not overhead, and way below any reasonable chain's capacity.
i
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'Good enough' works great, until it doesn't.
Small nylon slings are cheap, versatile and much nicer to use than chain. Failures of improper chain rigging either from material failure or more commonly by just coming unhooked, have seriously hurt far too many people and have led to many lawsuits.
It is usually the simple stuff that bites you when you least expect it.
Good luck, and 'Worksafe'
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Many a bumper has been ripped off by chains. Back when they had bumpers, that is. Now they just rip off the back third of the car.
Steve
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QWhat sized chain? You might get some pointers from the way these guys do it-

http://www.youtube.com/watch?v=2uvOgWapG2g&feature=channel

H.
;>
wrote:

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What size chain? That's easy. Always use bigger chain than you need. ;'-)
Steve
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