How much difference in chain quality?

[vyv_cox]

Vyv,
what do you mean by "weld as longs as the wire diameter"?

It was an attempt to avoid the problem of the one sample that failed quite badly. It looked very nice, shiny galvanising but the weld was unusually short, perhaps 2 mm wide in an 8 mm chain. It failed in the tensile test and in my bench test. Where the weld is wider, around 6 - 8 mm, it probably shows that the weld has been made well with adequate melting of the metal each side of it. This may be slightly misleading because the weld is trimmed after it is completed, but it is the only observation we can go on.

 

[Rossynant]

Well, it's a point of view. Personally, if buying a strength critical item like anchor chain I would prefer it to be 150% rather than 101%. Don't forget, we are not necessarily talking only of fracture, the yield point would be affected in a similar way.

Very recently I have read a couple of reports of boats in big blows where the chain stretched, turning it into almost a rigid bar. That would almost certainly not go through the gypsy, whereas the 150% stuff may well not have deformed at all.

BTW - for such situation the stud link chain (hope not messing the name) was better, but i guess no small sizes are available now. Not looking for it as in 8mm would be much heavier, but remember 10 mm one.
Any comment, please?

 

[vyv_cox]

BTW - for such situation the stud link chain (hope not messing the name) was better, but i guess no small sizes are available now. Not looking for it as in 8mm would be much heavier, but remember 10 mm one.
Any comment, please?

Bradney Chain say 'rarely below 12.5 mm http://www.bradneychain.com/products-page/marine/stud-link-chain/ I have to say that was news to me, as other (USA) sites seem to quote a minimum of 16 mm. I guess it must be very rare for loads in anchoring situations to be so high that the chain deforms but it's a good argument for using higher grades.

 

[Bilgediver]

It was an attempt to avoid the problem of the one sample that failed quite badly. It looked very nice, shiny galvanising but the weld was unusually short, perhaps 2 mm wide in an 8 mm chain. It failed in the tensile test and in my bench test. Where the weld is wider, around 6 - 8 mm, it probably shows that the weld has been made well with adequate melting of the metal each side of it. This may be slightly misleading because the weld is trimmed after it is completed, but it is the only observation we can go on.

No it is not misleading.. The removal of metal by shaving the weld is a normal part of the procedure. If little or no shaving was necessary then it may suggest skimping on the bar length used which may result in no enlargent of OD or more worringly maybe not 100% weld across the full diameter especially in the centre.

The weld is made by bending a length of bar to shap and enclosing the end link of the chain being made. The next stage is the electic welding of the join which is achieved by electrically welding across the join while the link is compressed. The pressure is maintained to the link is formed to the set length resulting in the circumfrencial bead at the join. This is then shaved off.

The amount of material removed is an indication of how overlong the original bar stock was . It would seem the European chain in this case may have been produced with bar stock of borderline lenght which not only produces little beading at the join but might also result in a lack of a 100% weld across the full diameter??????

 

[fortuneco123]

The chain quality is mainly described the proof load test, breaking load test etc