mick
Well-Known Member
Quite by chance I noticed this slightly ragged weld on my brand new grade 40 8mm chain. Could it compromise the strength of the chain? The link is, of course, right in the middle of the length.
Here's one for the metallurgists
- Thread starter mick
- Start date
nedmin
Well-Known Member
Yes,Looks to be about 15-20% weakere due to the 2 bits not being in line.If the manufacturer lets that go past quality control,whats the rest of the welds like?
D
Deleted member 36384
Guest
It probably will weaken the chain at that link. Two reasons: a step in the link causes an area where stress can be concentrated, the weld produces a Heat Affected Zone (HAZ) in the parent material which can make the parent metal harder and more brittle.
Of course, how much it will weaken it is not known. If the chain is manufactured to a specification then there may be a standard that the weld has to comply with to achieve the strength. For example the link weld may have a dimensional tolerance and the weld may have pre and post heat and rate of cooling to limit the negative aspects of the HAZ. I would certainly ask the supplier to check with the manufacturer.
Of course, how much it will weaken it is not known. If the chain is manufactured to a specification then there may be a standard that the weld has to comply with to achieve the strength. For example the link weld may have a dimensional tolerance and the weld may have pre and post heat and rate of cooling to limit the negative aspects of the HAZ. I would certainly ask the supplier to check with the manufacturer.
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Bilgediver
Well-Known Member
I think what you have here is a hand formed and hand welded joining link.
The chain is machine made and sometimes lengths are joined manually. Every link has a weld but it has been dressed after welding. That link has been hand closed and hand welded and not dressed. The chain would have been normalised after welding if required before galvanising.
It might not be appreciably weaker than the rest of the chain but the windlass might not like it.
Do you know whose chain it is?????? This could help re assure you or otherwise. IE If it is someone like Bradley then they have in house test and analysis equipment and their chain is usually quality controlled to the satisfaction of LLoyds , even if from China. If it is Plastimo then it is probably Maggi from Italy and so same comments as above but delete the Chinese references
However if it is from Mickey Mouse Marine in Havant etc then beware if they can not show certificates! They may have bought it from an unknown source without any proof of QC.BarryLeat
Member
Ragged Weld in Chain.
I am not a believer in welded chain for anchor use, one prefers forged links. Yes, its more expensive but you only get what you pay for. In my industry as soon as one used a weld in a component design, one automatically reduced the usable tensile strength of the welded material by 10%. The photograph also clearly shows a reduction in link crossectional area due to inadequate alignment during welding. This will also lead to a reduction of the load carrying capability of the chain. Welded chain would be manufactured from a low carbon weldable steel where the associated heat affected zones would not contain the hard brittle martensitic structure. This latter type of structure would necessitate a post weld heattreatment, a treatment not likely during chain manufacture. I would take the chain back to the supplier and say it is not acceptable for use where one is relying on good strength throughout its length
I am not a believer in welded chain for anchor use, one prefers forged links. Yes, its more expensive but you only get what you pay for. In my industry as soon as one used a weld in a component design, one automatically reduced the usable tensile strength of the welded material by 10%. The photograph also clearly shows a reduction in link crossectional area due to inadequate alignment during welding. This will also lead to a reduction of the load carrying capability of the chain. Welded chain would be manufactured from a low carbon weldable steel where the associated heat affected zones would not contain the hard brittle martensitic structure. This latter type of structure would necessitate a post weld heattreatment, a treatment not likely during chain manufacture. I would take the chain back to the supplier and say it is not acceptable for use where one is relying on good strength throughout its length
mick
Well-Known Member
Bilgediver;2869246 Do you know whose chain it is?????? [/QUOTE said:
sarabande
Well-Known Member
I'd be quite surprised if JG did not rapidly replace that purchase if you contact their office. Reputation is everything for on-line chandleries.
vyv_cox
Well-Known Member
I have been collecting chain samples for tensile testing. I was very surprised when I received the one from your supplier, as it was also very much like the one you show. Unfortunately due to my accident I will not be testing for some months, so cannot advise any results.
You will do very well to find anybody making forged chain in small sizes, i.e. up to about 12 mm. I am finding that the vast majority of it is supplied from China, of welded manufacture. There are a couple of exceptions but the ones I have found to date are also welded. I would be very pleased if you could point me to a supplier of forged links in 8 mm.
QFour
Member
Chain
Perhaps you should send your supplier a picture and see what response you get. Seems like everything we buy now days is made in China. They must wonder what we do with some of the items they send
Perhaps you should send your supplier a picture and see what response you get. Seems like everything we buy now days is made in China. They must wonder what we do with some of the items they send
charles_reed
Well-Known Member
Living close to the centre of UK chain-manufacture, I, too, have to look askance of anyone looking for forged chain in 8-10-12mm sizes.
Bye-the-bye, Bradneys, they tell me, now purchase all their "domestic" chain in China, then test and certify for EC.
Seajet
...
Maybe this is a good time to point out that nylon warp is a lot more trustworthy, has stretch to allow for snatching in waves if things at an anchorage become unpleasant or dangerous, and saves HUGE amounts of weight on a boat !
Weight slows a small boat down, speed is safety, getting to port ahead of bad weather, or allowing responsiveness to steer through and among waves.
A resposive boat is also a great deal more fun to sail than a pudding...
I am not saying any of this from a racing point of view, although I have done a lot of dinghy & a fair bit of keelboat racing ( mainly racing in winter for safety cover, 'fast cruising' in summer ) I sail my 22' cruiser / racer alone or with novice girlfriend crew, so 'speed IS safety', as long as one's boat is well balanced and behaved.
As long as one has a decent length of good heavy ( allowing for forged ? My - I think - 1/4" chain doesn't seem to have the welds described ) chain at the anchor, to both cope with seabed chafe and give a low angle of pull on the anchor ( with an angel if necessary for deep fin keelers to prevent 'sailing the anchor' & wrapping the anchor warp against the keel, no hardship rigging an angel & it and DOES assist holding ) - one has the best of all worlds, or maybe when considering weight, the least worst !
At places like Chichester Harbour's East Head, where space is at a premium if available at all, one can usually hold happily on a short (3-4 X depth ) scope for lunch hooking if not leaving the boat, and at quieter anchorages the angel will help restrict the swinging circle - if a strong blow comes up all boats should stream in the same direction, though of course an eye should be kept out at change of tide direction - not necessarily HW -.
Maybe time for boats, definitely in the case of 25' or less, to learn 'all chain' is certainly not 'all good' ?
As for getting decent forged chain, sounds like a gap in an expensive market...
Weight slows a small boat down, speed is safety, getting to port ahead of bad weather, or allowing responsiveness to steer through and among waves.
A resposive boat is also a great deal more fun to sail than a pudding...
I am not saying any of this from a racing point of view, although I have done a lot of dinghy & a fair bit of keelboat racing ( mainly racing in winter for safety cover, 'fast cruising' in summer ) I sail my 22' cruiser / racer alone or with novice girlfriend crew, so 'speed IS safety', as long as one's boat is well balanced and behaved.
As long as one has a decent length of good heavy ( allowing for forged ? My - I think - 1/4" chain doesn't seem to have the welds described ) chain at the anchor, to both cope with seabed chafe and give a low angle of pull on the anchor ( with an angel if necessary for deep fin keelers to prevent 'sailing the anchor' & wrapping the anchor warp against the keel, no hardship rigging an angel & it and DOES assist holding ) - one has the best of all worlds, or maybe when considering weight, the least worst !
At places like Chichester Harbour's East Head, where space is at a premium if available at all, one can usually hold happily on a short (3-4 X depth ) scope for lunch hooking if not leaving the boat, and at quieter anchorages the angel will help restrict the swinging circle - if a strong blow comes up all boats should stream in the same direction, though of course an eye should be kept out at change of tide direction - not necessarily HW -.
Maybe time for boats, definitely in the case of 25' or less, to learn 'all chain' is certainly not 'all good' ?
As for getting decent forged chain, sounds like a gap in an expensive market...
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Skylark
Well-Known Member
I've just Googled Grade 40 8mm chain. The best way to answer your question is to compare what you have against its product specification.
It should be produced against an ISO 4565 spec. The BSI website wants £45 to buy a copy so I've drawn a blank
Did you buy calibrated chain? Perhaps the mis-form will foul the windlass? That would be a good reason to reject it.
It should have a breaking load of just over 4 tonne with a SWL of 1000kg, that's a good factor of safety.
If you are concerned about it and if it's new, I'd ask the supplier to do the honourable thing and change it. Your concerns are unlikely to deminish with the passage of time.
It should be produced against an ISO 4565 spec. The BSI website wants £45 to buy a copy so I've drawn a blank
Did you buy calibrated chain? Perhaps the mis-form will foul the windlass? That would be a good reason to reject it.
It should have a breaking load of just over 4 tonne with a SWL of 1000kg, that's a good factor of safety.
If you are concerned about it and if it's new, I'd ask the supplier to do the honourable thing and change it. Your concerns are unlikely to deminish with the passage of time.
mick
Well-Known Member
Thanks, all.
Bilgediver
Well-Known Member
Jimmy Green do emphasize quality and would no doubt discuss your problem. See whos certificates they provide if you request them. I believe their chain is supposed to be European however in this modern age that is no guarantee it didn t start life somewhere else.
Oh yes ignore those comments about getting forged chain. 99.9 % chain used on ships and boats has welded links. You willl be laughed out of court if you ask anyone to quote you forged 8mm chain .The nearest you will get to forged chain is studded chain where a forged stud is inserted in welded chain. It is not unusual for chain to be normalised(heat treated) after welding to restore the material to the required condition.
Usually anchor chain is made using an automated process with the links being formed then closed together and the join formed by electric welding as the ends are pressed together. This produces a flange effect at the join which is automatically shaved of. Sometimes this dressed bit is a slightly smaller diameter than the body section of the link but this is of no consequence.
When a link is made manually it is closed in a similar way to make the link shape and then the electric current is passed across the link. Yes the link forms a short circuit but yes it does work. As I said before the joining link on yours was badly formed.....Maybe the lads in the factory had been on the Buckfast! The link ends were not formed so they met when the electric welding process was completed so the dressing would have been a problem. They should have cut out the link and done another one correctly.
I think Jimmy Green would look at satisfying you if you approached them in the right manner and no doubt they could sell the shorter lengths in due course.
By the way when we test chain on the rigs we do not test to destruction. and I wouldn t consider it for this. We do a proof test and so a test of 1.5or 2 X SWL.
Bilgediver
Well-Known Member
Would be easier to find Pink Elephants dancing in T Tu's in Mayfair!!!
I suspect those folk on here stating a love of forged chain do not understand that all chain is forged to an extent....IE it is a forging process that is used to convert the straight lengths of round bar to a chain link. however with most chain the next process is to use an electric arc to join the link. This is done by connecting jumper leads to the link immediately above and below the gap and at the same time the current flows the link is squeezed. It is an electric weld . There is some very expensive chain available done by other processes but this is not usually considered for normal commercial operations due to cost. Generally someone selling "forged" anchor chain is probably selling bog standard chain where the link material was heated and bent to shape"forged" and then the join was electrically welded using an electric current across the join and closing pressure on the join at which point the link also becomes the correct size.
If some one describes chain as welded it will not be an inferior product! It is the normal description for what you get off the shelf.
As I have said elsewhere in this case the OP had a chain length that had been made up from two lengths of chain plus a manually made joining link. The joining link appears to be have badly formed before the welding process.