Is it possible to mix grade 80 chain and grade 100 components on a sling assembly?
In simple terms, yes – BUT the assembly can only be rated at the grade 80 WLL. Here is an example: A sling is made with grade 100 chain and the hooks used for the sling are grade 80. This sling would need to have a tag with a grade 80 working load limit (WLL) of the weakest component.
For your reference I have provided the following applicable standards:
ASME B30.9, 9-1.5.7
When components of a sling have a lower rated load than the alloy chain with
which it is being used, the sling shall be identified with a rated load consistent
with the lowest load rating of any of the components.
Hooks, rings, oblong links, pear shaped links, welded or mechanical coupling
links or other attachments shall have a rated capacity at least equal to that of
the alloy steel chain with which they are used or the sling shall not be used
in excess of the rated capacity of the weakest component.