Chain Preparation for Welding

[RaymondR]

I needed to join some anchor chain I had had galvanized. I weld my chain to join it because I tend to the opinion that this method gives the best result.

The first image shows an end link being cross cut on the link end. Both ends of the chain are prepared in this manner.

The second image shows the two X cut links.

The third image shows the end links being linked together ready for welding.

[Reefmagnet]

Clever way to join chain! One suggestion I would make would be to cut at the original flash butt weld so that the welded joints are away from the loading points when in use.

[a64pilot]

I wouldn’t. Will it go thought a gypsy like that? What rod are you using, what grade of chain is it?
You did remove the zinc from the area to be welded?

[slug]

Originally Posted by RaymondR

I needed to join some anchor chain I had had galvanized. I weld my chain to join it because I tend to the opinion that this method gives the best result.

The first image shows an end link being cross cut on the link end. Both ends of the chain are prepared in this manner.

The second image shows the two X cut links.

The third image shows the end links being linked together ready for welding.

Is a weld stronger than a common chain link ?

[a64pilot]

Originally Posted by slug

Is a weld stronger than a common chain link ?

Properly executed, ANY weld is stronger than the parent material.
That is sort of a basic tenet of being a welder, which I was, but many years ago.
I’m cheap, ask my Wife, but I won’t join chain, even though I know it’s very often done and with good results, the potential loss just isn’t worth the savings to me.

[Simi 60]

Originally Posted by slug

Is a weld stronger than a common chain link ?

Common chain links that are actually rated and tested for 13mm chain are rare as rocking horse sh1te in Australia.
Especially if you want one to go through a chainwheel

[NCWDave]

Buff it clean with a wire wheel n weld it with 7018 it will be fine. If u want to be picky buff up the inside of the bend with a rat tail file. If you dont want to clean it up run 6010 or 6011. The only concern I could imagine is a high carbon heat treated chain like some rigging chains.

[Reefmagnet]

Yeah, I wouldn't trust those hammer down pin arrangements as far as I could throw them. It looks to me like one decent shock load can shear those pins and then it will be all downhill from there. No doubt they work fantastic when hanging off a statically loaded crane, but as an anchor chain joiner soaking in brine, I'm not so sure. A welded chain will be plenty strong as long as it has full penetration, is welded with the correct filler material and is dressed to remove any irregularities and stress concentration points. That might sound like you need to be X-ray certified to do the job, but chain is very easy to weld.

[Muaddib1116]

What about using those pinned connectors, but instead of using the pins, plug welding the pin holes and maybe even welding around the seam?

[Simi 60]

Originally Posted by Reefmagnet

Yeah, I wouldn't trust those hammer down pin arrangements as far as I could throw them. It looks to me like one decent shock load can shear those pins and then it will be all downhill from there. No doubt they work fantastic when hanging off a statically loaded crane, but as an anchor chain joiner soaking in brine, I'm not so sure. A welded chain will be plenty strong as long as it has full penetration, is welded with the correct filler material and is dressed to remove any irregularities and stress concentration points. That might sound like you need to be X-ray certified to do the job, but chain is very easy to weld.

Some are better than others

Drop forged Crosby or Acco / Peerless / PWB (Kito) are at least rated

I just bought this box of 10 from the US, I had only ever searched for the Crosby variant before and they were near impossible to find.

Of interest, these are made in Japan
But it does say not for lifting.

I'll run a soft shackle backup with them as well.
And as it will be 80m + 40m, will very rarely if ever see light of day.

[RaymondR]

I put the welds on the ends rather than where the chain is welded during manufacture so that the welds are in shear under load. I suspect that even a poor quality weld in shear would exceed the tensile load rating of the chain.

I try to slightly over build the welds. Other than slag removal I don't do any post weld work on the chain and have not had any problems with it passing through the anchor winch.

I did not notice what the rods are as I bought them for welding the chain years ago and as I only use about one each time the packet will see me out. However I suspect they are 7018 which is I believe a low hydrogen designation.

I would like to run some tests on comparative breaking strength of the chain to see whether the welded links fail before the chain is stretched but don't have access to a centre hole jack big enough.

[Cadence]

I would imagine it depends on how good the welder is. A real pro can probably make the joint better than new. I'd cut on the length of the link.
The guy that has a large assortment of rods kept in an airtight environment and has a welder the size of a house reefer and inert gas tanks sitting around.
JMHO, You don't want me doing it with a buzz box.

[jhulmer]

Originally Posted by RaymondR

I needed to join some anchor chain I had had galvanized. I weld my chain to join it because I tend to the opinion that this method gives the best result.

The first image shows an end link being cross cut on the link end. Both ends of the chain are prepared in this manner.

The second image shows the two X cut links.

The third image shows the end links being linked together ready for welding.

Raymond

If you are welding the two links together that puts the full force on the weld its self. It would be better If you weld only one link closed. That divides the force in half to only one weld. That is why you see the weld on the side of chain links.

Would you agree?
Jim

[RaymondR]

The reason for cutting on the ends of the links is that it is the place where least tensile loading of the links occurs. Whether or not it's sound, my reasoning is that a poor weld is less likely to fail under shear loading than under tensile.

[Eigenvector]

Just to add some engineering to this discussion..........


A)Links are typically welded mid side due to the way high speed chain making machine hold the links during resistance welding.


B) For chain grades such as G70, G40 etc, the 70&40 refer to a maximum tensile strength of 700 N/mm and 400 N/mm respectively. A grade 50 would be approximately 70 ksi which could theoretically be welded with 70 series filler material (ie 7018). This would also assume that the chain is not heat treated alloy.



c) Shear strength is 1/2 the Tensile strength, so putting he weld at the end gains nor looses anything, assuming it's pure shear, which it's not.


But, that was a slick way to cut the links to eliminate having to bend. I'll have to remember that.