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| Introduction
to Chain Slings |
• Care & Use
of Chain Slings
•
Working Load Limits of Alloy Chain Slings
• Campbell®
Chain Sling Program
Alloy chain slings are often selected when operating
under high temperatures or rugged conditions that would abrade or
destroy other types of slings. They are flexible, durable and long
lasting, ductile, easy to inspect, collapsible for convenient storage,
and will adhere securely to the contours of a load. Although chain
will show little or no stretch at rated capacity, it does have the
ability to elongate up to 20% prior to failure. This elongation serves
as a visual warning sign prompting users to remove the sling from
service before injury or damage is sustained from a broken chain sling.
Perhaps the most advantageous feature of a chain sling is its ability
to be repaired. Nearly any damaged component discovered during an
inspection can be repaired and restored to useful condition. During
the repair process, slings will be refurbished, proof tested and recertified,
offering an economical alternative to new chain sling replacements.
Chain slings used for overhead lifting
applications must be manufactured from alloy steel.
Alloy chain, commonly 8600 series alloy, is subjected to quality
control techniques surpassing those applied to lower grades of chain
and is designed, approved and specifically recommended for overhead
lifting. Alloy steel chains possess the strength, chemical content
and mechanical properties necessary to meet government and industry
standards. These specifications prescribe minimum elongation values,
minimum proof test values, recommended working load limits and minimum
statistical breaking strengths. Alloy chain can be distinguished from
other popular grades of welded chain through its hallmark, or identification
code, which is embossed into chain links approximately every 12"
to 18". Grade 80 (or System 8) is the most frequently used alloy
chain and carries a hallmark similar to Campbell Chain Company's "CA8"
or "C8". A new, maximum strength Grade 100 (or System 10)
alloy is manufactured by Campbell Chain with a "C10" hallmark
for easy identification. Do not use any chain sling for overhead lifting
before verifying that it is constructed of alloy steel. Different
"Types" of chain slings can be fabricated and are usually
designated by a three character symbol, based upon the number of legs
and types of components used in the assembly: |
First Character (Basic Type of Construction):
S = Single leg sling
SB = Single basket
D = Double leg sling
DB = Double basket
T = Triple leg sling
SE = Single endless basket
Q = Quadruple leg sling
DE = Double endless basket
C = Single leg sling with master link at each end
Second Character (Type of Master Link or End Link):
O = Oblong master link (recommended for all
assemblies)
P = Pear shaped master link (upon request only)
Third Character (Type of Hook):
S = Sling hook
G = Grab hook
F = Foundry hook |
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| Chain
slings can be manufactured using permanent, welded coupling links,
or if preferred, mechanical coupling links for quicker "in the
field" assemblies. Either way, the sling must have an attached
identification tag providing the grade, size, reach, type of sling,
working load limit at a specific angle of lift, and serial number.
Relative to other types of slings, chain slings have the poorest strength/weight
ratio, best abrasion and cut resistance, average elongation and shock
resistance, best flexibility, and best resistance to high temperatures. |
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