When used in rigorous material handling applications,
chain can easily become worn or corroded. It is important to inspect chain for defects on a regular basis to avoid
an unsafe lifting condition or even operator injury. When
corrosion and wear occur, it results in a reduction of link
cross-section which can lead to decreased strength of the
Corrosion can occur anywhere chain comes in contact
with harsh chemicals, water or when it is used in tough environments.
Wear can occur in any portion of a link that is subject to
contact with another surface. The natural shape of chain
confines wear, for the most part, to only two areas. These
are, in order of importance, (a) at the bearing points of
interlink contact, and (b) on the outsides of the straight side
barrels that may be scraped from dragging chains along hard
surfaces or out from under loads.
When wear or corrosion is observed, the next step is to
determine how severe the damage is and if the chain can still
be safely used. General surface corrosion can be removed
by cleaning and oiling the chain. If pitting is observed after
cleaning and oiling, remove from service. Next, the operator
should take a caliper measurement across the worn section
of chain and compare it to the minimum allowable dimension for that chain.
A visual link-by-link inspection is the best way to detect
dangerously stretched alloy chain links. Reach should also
be measured from the upper bearing point on the master
link to the bearing point on the lower hook. The smallest
sign of binding or loss of clearance at the juncture points of
a link indicates a collapse in the links’ sides due to stretch.
Any amount of stretch indicates overloading, and the chain
should be removed from service.
Note that a significant degree of stretch in a few individual links may be hidden by the apparent acceptable length
gauge of the overall chain. This highlights the importance of
Alloy steel sling chain typically exhibits well over 20%
elongation before rupture. The combination of elongation
and high strength provides energy absorption capacity.
However, high elongation or stretch, by itself, is not an adequate indicator of shock resistance or general chain quality
and should not be relied upon by riggers to provide advance
warning of serious overloading and impending failure.
Overloading must be prevented before it happens by selection of the proper type and size of slings. Again, any amount
of stretch is overloading and the chain should be removed
There is no short-cut method that will disclose all types of
chain damage. Safety can only be achieved through proper
inspection procedures. There is no adequate substitute for
careful link-by-link scrutiny.
Since first published on July 27, 1975, the OSHA Chain
Sling Inspection section has undergone very few changes.
These regulations have and continue to serve as a comprehensive guide for those responsible for chain sling inspection. For a full review of the applicable sections of the Code
of Federal Regulations ( 29 CFR 1910.184), visit www.
Peter Cooke is a Training Manager specializing in
Rigging & Load Securement for Columbus McKinnon
“The smallest sign
of binding or loss
of clearance at the
juncture points of
a link indicates a
collapse in the links’
sides due to stretch.
Any amount of stretch
and the chain should
be removed from