Figure 6-22.Stress on slings at various vertical angles.
Table 6-1.Safe Working Load of Chains
and stopped. The impact load is several times the
weight of the load.
HANDLING AND CARE OF CHAIN
When hoisting heavy metal objects using chain for
slings, you should insert padding around the sharp
comers of the load to protect the chain links from
Store chains in a clean, dry place where they will
not be exposed to the weather. Before storage, apply a
light coat of lubricant to prevent rust.
Do NOT perform makeshift repairs, such as
fastening links of a chain together with bolts or wire.
When links become worn or damaged, cut them out of
the chain, then fasten the two nearby links together
with a connecting link. After the connecting link is
closed, welding makes it as strong as the other links.
For cutting small-sized chain links, use bolt cutters.
To cut large-sized links, use a hacksaw.
Inspect the chain to ensure it is maintained in a
safe, operating condition. A chain used continuously
for heavy loading should be inspected frequently.
Chain is less reliable than manila or wire rope slings
because the links may crystallize and snap without
Examine the chain closely link by link and look
for stretch, wear, distortion, cracks, nicks, and gouges.
Wear is usually found at the ends of the links where
joining links rub together. If you find wear, lift each
link and measure its cross section.
NOTE: Remove chains from service when any
link shows wear more than 25 percent of the thickness
of the metal.