Alloy Chain Slings

Alloy steel chains are often used because of their strength, durability , abrasion resistance and ability to conform to the shape of the loads on which they are used. In addition, these slings are able to lift hot materials.

Alloy steel chain slings are made from various grades of alloy, but the most comon grades in use are grades 80 and 100. These chains are manufactured and testing accordance with ASTM (American Society for Testing and Materials) guidlines. If other grades are used, use them in accordance with the manufacturer’s recommendations and guidelines.

Identification:

New slings are marked by the manufacturer to show:

  • Size
  • Grade
  • The rated load
  • Length (reach)

In addition, slings may be marked to show:

  • Number of legs
  • Individual sling identification (i.e. serial number)
  • Name or trademark of manufacterer

Rated Loads:

Rated loads are based on:

  • Material strength
  • Design factor
  • Type of hitch
  • Angle of loading

Do not use horizontal angles less than 30 degrees except as recommended by the sling manufacturer or a qualified person.

Attachments:

Use attachments, such as hooks, rings, oblong links, pear-shaped links, or welded or mechanical coupling links that have a rated capacity at least equal to that of the alloy steel chain with which they are used. If attachments with capacities lower than the chain are used, ensure that the sling is rated to the weakest component used on the sling.

Inspections:

Designate a qualified person to inspect lings and all fastenings and attachments each day before use for damage or defects.

This qualified person also performs additional perodic inspections where service conditions warrant, as determined on the basis of:

  • Frequency of sling use
  • Severity of service conditions
  • Nature of the lifts being made
  • Experience gained during the service life of slings used in similar situations.

Make periodic inspections of alloy steel chains slings at intervals no greater than 12 months. A good guide to follow includes:

  • Yearly for normal service use
  • Monthly to quarterly for sever service use
  • As recommended by a qualified person for special and infrequent service use.

Develop a system to make sure that these inspections are conducted. To do this, you can use a recordkeeping system, such as logs or marking the inspection date on a tag on the sling.

Make a thorough inspection of slings and attachments. Items to look for include:

  • Wear
  • Defective welds
  • Nicks, cracks, breaks, gouges, stretch, bends, discoloration due to excessive heat
  • Excessive pitting or corrosion
  • Throat opening of hooks
  • Missing or illegible sling identifications
  • Other conditions that cause doubt as to continued safe use of the sling

Where any such defect or deterioration is present, remove the sling or attachments from service immediately.

Repairing/Reconditioning

Do not use worn or damaged alloy steel chain slings or attachments. Discard or repair them. Use damaged slings only after they are repaired, reconditioned, and proof tested by the sling manufacturer or a qualified person using the following criteria:

  • Ensure that slings and attachments conform to the original strength requirements
  • Mark those slings or attachments to identify who made the repairs
  • Replace rather than repair crack, broken, or bent links
  • Do not use mechanical coupling links or carbon steel repair link to repair broken lengths of alloy chain.

Operating Practices

Do not use alloy steel slings with loads exceeding the rated loads (capacities). Ensure that alloy steel chains are used only in accordance with the manufacturer’s recommendations. Follow other safe operating practices including:

Sling Selection

  • For multiple-leg slings used with nonsymmetrical loads, ensure that an analysis by a qualified person is performed to prevent overloading of any leg
  • Ensure that operations at other angles are limited to the rated load of the next lower angle given in the tables or calculated by a qualified person.
  • Do not use a component unless it is the proper shape and size to ensure that it is properly seated in the hook or lifting device.

Cautions to Personnel

  • Ensure that all the portions of the human body are kept away from the areas between the sling and the load and between the sling and the crane or hoist hook
  • Ensure that personnel never stand in line with or next to the legs of a sling that is under tension
  • Ensure that personnel do not stand or pass under a suspended load
  • Ensure that personnel do not ride the sling or the load, unless the load is specifically designed and tested for carrying personnel

Effects of Enviroment

  • Store slings in an area where they will not be subjected to mechanical damage, corrosive action, moisture, extreme temperatures, or to kinking
  • When slings are exposed to extreme temperatures, follow the guidance provided by the sling manufacturer or qualified person.

Rigging Practices

  • Ensure that slings are hitched in a manner providing control of the load
  • Ensure that sharp edges in contact with slings are padded with material of sufficient strength to protect the sling
  • Ensure that slings are shortened or adjusted only by methods approved by the sling manufacturer or qualified person
  • Ensure that during lifting, with or without a load, personnel are alert for possible snagging
  • Ensure that, in a basket hitch, the load is balanced to prevent slippage
  • When using a basket hitch, ensure the legs of the sling contain or support the loads from the sides, above the center of gravity, so that the load remains under control
  • Ensure that, in a choker hitch, the choke point is only on the sling body, never on a fitting
  • Ensure that, in a choker hitch, an angle of choke less than 120 degrees is not used without reducing the rated load
  • Ensure that slings are not constricted, bunched, or pinched by the load, hook, or any fitting
  • Ensure that the load applied to the hook is centered in the base (bowl) of the hook to prevent point loading on the hook, unless the hook is designed for point loading
  • Do not shorten or lengthen a sling by knotting or twisting
  • Do not rest loads on the sling
  • Do not pull a sling from under a load when the load is resting on the sling
  • Do not drag slings on the floor or over abrasive surfaces
  • Do not allow shock loading
  • Avoid twisting and kinking

Proof Testing:

Before initial use of a sling, ensure that every component of a new, repaired, or reconditioned alloy steel chain sling has been proof tested by the sling manufacturer or a qualified person and meets the requirements of the American Society of Testing and Materials Specification A906-02.

Retain the certificates of proof test and make them available for examination

Enviromental Effects:

Do not use alloy steel chains that have been heated above 1,000 degrees F (538 degrees C). Remove them from service. Alloy chain slings exposed to temperatures above 400 degrees F (205 degrees C) have reduced load ratings.

If chain slings are to be used at temperatures below minus 40 degrees F (minus 40 degrees C), consult the chain manufacturer.

The strength of alloy steel chain slings can be affected by chemically active environments. Consult the manufacturer before the sling is to be used in chemically active environments.

Effects of Wear:

Do not use chains if the size at any point of a link is less than that stated in the table below. Remove the sling from service.

Minimum Allowable Thickness at Any Point on a Link

Nominal Chain or
Coupling Link Size
 Minimum Allowable
Thickness at Any Point on
The Link
 
In "MmInmm
7/325.50.1894.8
9/3270.2396.07
5/1680.2736.93
3/8100.3428.69
1/2130.44311.26
5/8160.54613.87
3/4200.68717.45
7/8220.7519.05
1260.88722.53
1 1/4321.09122.71