Identifying chain-link strength

[striderzz]

I am talking about chain-link chain, the kind you use to pull a stuck car or anchor something on a trailer.

I have a hand me down piece of chain, about 20', and I am trying to figure out how strong it is. Both clevis hooks say "Crosby" and both say "5/16". One hook also says "Forged USA" with "N50" next to it. The other hook says "Alloy T80".

I did research on google and found G80 but no T80. Also, I could not easily find 5/16 chain, only 9/32 and 3/8.

Any insight? I am fairly certain my near future will involve moving a lot of trees off the road.
http://www.arboristsite.com/forestry-logging-forum/243430.htm

Thanks
-n

 

[Steve NW WI]

Crosby is good quality stuff, commonly used in hoists and other rigging applications. Double check for any more markings, the 50 is not making sense as there's no "Grade 50" chain that I know of. It could well be G80 though. Pics might help a bit, also the chain links on higher grade (usually G70 and above) will be stamped with the grade, or at least an abbreviation of it, I.E. 8 instead of G80.

Here's a good general info chain page: Chain Grading

 

[striderzz]

Here is a picture of the hook that says "alloy t80"

I will check the links to see if they are stamped

Thanks!
-n

 

[AVB]

Here is a picture of the hook that says "alloy t80"

I will check the links to see if they are stamped

Thanks!
-n

That just means that hook is a grade 8 designed for overhead lifting. The chain strength need to be determined as just about any 5/16 could used to make the length between the hooks especially if the hooks has removable pins..

 

[rocketnorton]

transport chain is g7 & links are marked as well as hooks. g8 is lift chain, has marks &/or tags if certified for lift. 5/16 is a common size.