Stretch of Welded Chain

[WillisV]

Anybody have a resource/information on how to accurately determine the elongation/stretch of welded chain (specifically Gr80 Allow chain, but I am open to anything) under a certain load? I guess I am looking for some sort of effective area / modulus similar to how you calculate cable stretch but thus far have come up empty.

 

[JAE]

Seems like that would be heavily dependent upon the change link configuration, bend radius, and number of links per unit of length.

I don't have anything on that. Google search?

 

[WillisV]

Agree JAE - and I have Googled to no avail. Best I can find is minimum elongations at breaking loads but that is not really what I am looking for.

 

[SAIL3]

that would be a bear to calculate and the results could be highly inaccurate.....test data would be the most accurate if available....I would try chain manufacturers to see if they have run any test on these...

 

[boo1]

test them
see NACM_Welded

GR80 uses ASTM Specification A391

https://law.resource.org/pub/us/cfr/ibr/003/astm.a391.1965.pdf

 

[3DDave]

I agree with SAIL3. The chain makers are going to be your best source. The reliable ones do tests on every batch to verify the ultimate performance of their chain. More important, they are the only ones who can have information about the distribution of the results - it won't be one number but a range. Your design may need 1 to 3 sigma performance, but if you don't know what the range is, you won't know what to plan for.

 

[DBronson]

WillisV

Chain properties are given on page 236 of the catalog. If you need more info I'd call Crosby Tech Support.

Link

Regards,
DB

 

[racookpe1978]

The weight of loose chain links, and the absolute inability to resist ANY movement is going to mean you will always get a catanary. Pulling out that catanary is going to be many times MORE distance than the very little "stretch" of the individual chain links themselves.

Further, if any chain link has a casting "flaw" or machined irregularity/remnant/flaw so the "perfect" loop is distorted by that bump, then under load the difference in length may not be chain stretch but just the rough spots getting smoothed out.

 

[racookpe1978]

Thinking about my above, you'd need to test the chains vertically. Then at least you'd have a chance of getting repeatable results.

 

[boo1]

We test tie down chain assemblies regually. They do stretch....